JP7593285B2 - Integrated Circuits - Google Patents

Description

This disclosure relates to integrated circuits.

Conventionally, semiconductor integrated circuits (hereinafter, also referred to as integrated circuits) that integrate a variety of functions are known. For example, the following Patent Document 1 describes a technology in which the functions of an integrated circuit are switched according to a mode select signal input from outside the integrated circuit.

Japanese Patent Application Publication No. 6-43222

For example, one possible function of the above-mentioned integrated circuit is to output a drive signal to multiple types of external circuits that can be connected to the outside of the integrated circuit according to the type of external circuit. One possible external circuit is a so-called power supply circuit that is driven by a drive signal to output a predetermined voltage.

In such an integrated circuit, it is thought that a terminal for outputting a drive signal corresponding to the type of external circuit is required for each type of external circuit. It is also thought that a terminal for switching the function of the integrated circuit so as to output a drive signal corresponding to the connected external circuit is required. In other words, in an integrated circuit that is connected to multiple types of external circuits, a problem may arise in that the number of terminals connecting to the external circuits increases.

One aspect of the present disclosure provides a technique for reducing the number of terminals for connecting to multiple types of external circuits in an integrated circuit that is connected to external circuits.

One aspect of the present disclosure is an integrated circuit (15) that includes a group of connection terminals (62, 63, 64), a judgment terminal (65), an identification signal unit (54), and a start-up control unit (50). The group of connection terminals includes a plurality of terminals. The group of connection terminals is connected to a first circuit (13) at some of the group of connection terminals (64), and is connected to a second circuit (14) at all of the group of connection terminals. The judgment terminal is an external circuit connected to the integrated circuit, and acquires an output voltage from one of the first circuit and the second circuit.

The identification signal unit is configured to output an identification signal from a specific terminal. The specific terminal is a predetermined specific terminal from the group of connection terminals. The specific terminal is a terminal that, when a predetermined identification signal is output from the specific terminal, produces a different output voltage when a first circuit is connected to the integrated circuit as an external circuit and when a second circuit is connected to the integrated circuit as an external circuit. When the identification signal is output, the start-up control unit is configured to obtain the output voltage from the external circuit via the determination terminal, and operate in either a first mode for driving the first circuit or a second mode for driving the second circuit based on the output voltage.

According to this configuration, in an integrated circuit connected to multiple types of external circuits, the terminal connected to the first circuit is also used as a terminal of the connection terminal group connected to the second circuit. Furthermore, the control mode, such as the first mode and the second mode, is automatically switched based on the difference in the output voltage of the external circuit when an identification signal is output from a specific terminal of the connection terminal group. In other words, there is no need to provide a new terminal connected to the outside in order to input a signal from the outside for switching the control mode.

As a result, in an integrated circuit that is connected to multiple types of external circuits, the number of terminals for connecting to the external circuits can be reduced.

FIG. 2 is a block diagram showing a configuration of an ECU when a general-purpose IC is connected to an ASIC as an external circuit. FIG. 2 is a block diagram showing a configuration of an ECU when a switching circuit is connected to an ASIC as an external circuit. 4 is a flowchart showing a process executed by an ASIC according to the first embodiment. 4 is a timing chart illustrating the operation of the ASIC according to the first embodiment. 10 is a flowchart showing a process executed by an ASIC according to a second embodiment. 6 is a timing chart illustrating the operation of an ASIC according to a second embodiment. FIG. 13 is a block diagram showing a configuration when a general-purpose IC is connected as an external circuit to the comparative example. FIG. 13 is a block diagram showing a configuration when a switching circuit is connected as an external circuit to a comparative example.

Hereinafter, exemplary embodiments of the present disclosure will be described with reference to the drawings.
[1. First embodiment]
[1-1. Overall configuration]
The configuration of the ASIC 15 according to this embodiment will be described with reference to Figures 1 and 2. The ASIC 15 is an abbreviation for application specific integrated circuit, which is a general term for an integrated circuit in which multiple functional circuits are integrated into one for a specific application. The ASIC 15 is used, for example, in an electronic control unit (hereinafter, ECU 1) mounted on a vehicle. ECU 1 is an abbreviation for Electronic Control Unit.

The ECU 1 is equipped with a microcomputer 11 as a circuit for implementing the predetermined functions of the ECU 1, but the configuration of the power supply circuit that supplies the operating power supply voltage to the microcomputer 11 may differ depending on the type of ECU 1 or the type of microcomputer 11.

For example, the ECU 1 (hereinafter also referred to as the first ECU 1a) shown in FIG. 1 includes a microcomputer 11 (hereinafter also referred to as the first microcomputer 11a), and the first microcomputer 11a is supplied with a power supply voltage for operation by a general-purpose IC 13 described later. Hereinafter, the power supply voltage for operation of the microcomputer is also referred to as a secondary power supply voltage V2. For example, the ECU 1 (hereinafter also referred to as the second ECU 1b) shown in FIG. 2 includes a microcomputer 11 (hereinafter also referred to as the second microcomputer 11b), and the second microcomputer 11b is supplied with a secondary power supply voltage V2 by a switching circuit 14 described later.

The general-purpose IC 13 and the switching circuit 14 are power supply circuits that have the function of supplying a predetermined secondary power supply voltage V2. When the general-purpose IC 13 and the switching circuit 14 are connected to the ASIC 15, they are driven by a control signal supplied by the ASIC 15, and generate the secondary power supply voltage V2 from the predetermined primary power supply voltage V1.

ASIC 15 is capable of driving the connected external circuit, regardless of whether general-purpose IC 13 or switching circuit 14 is connected as the external circuit. An external circuit is a circuit that is actually connected to ASIC 15 (i.e., connected to ASIC 15). Capable of driving an external circuit means that it is possible to cause an external circuit (i.e., general-purpose IC 13 or switching circuit 14) to realize the function that the external circuit has (i.e., the function of generating a specific voltage as a power supply circuit).

Below, we will first explain the first ECU 1a that includes an ASIC 15 to which a general-purpose IC 13 is connected as an external circuit, and the second ECU 1b that includes an ASIC 15 to which a switching circuit 14 is connected as an external circuit. We will then explain the ASIC 15 that can drive an external circuit regardless of whether a power supply circuit such as the general-purpose IC 13 or the switching circuit 14 is connected as an external circuit.

In this embodiment, for example, the primary power supply voltage V1 is 6 V and the secondary power supply voltage V2 is 1 V, but the primary power supply voltage V1 and the secondary power supply voltage V2 are not limited to these values.

<ECU equipped with ASIC to which general-purpose IC is connected>
As shown in FIG. 1, the first ECU 1 a includes a first microcomputer 11 a, a general-purpose IC 13, an ASIC 15, a coil 17, and a capacitor 16.

The first microcomputer 11a includes a CPU and memory (not shown), and the CPU of the first microcomputer 11a executes a program stored in the memory to realize at least a part of the functions of the first ECU 1a. The first microcomputer 11a is driven by the supply of a secondary power supply voltage V2 (e.g., 1 V) generated by the general-purpose IC 13.

The general-purpose IC 13 has an enable terminal (hereinafter, ENA terminal 30), an IN terminal 31, and an OUT terminal 32 as terminals for connecting to the outside of the general-purpose IC 13. The ENA terminal 30 is connected to the ASIC 15 (i.e., the VGL terminal 64 described later). The IN terminal 31 is supplied with a primary power supply voltage V1 for operating the general-purpose IC 13. The OUT terminal 32 is connected to one end of the coil 17, and is connected to a power supply input terminal (not shown) of the microcomputer 11 via the coil 17.

When an enable signal is provided to the ENA terminal 30 as a first control signal generated by the ASIC 15, the general-purpose IC 13 steps down the primary power supply voltage V1 to generate a secondary power supply voltage V2, which is a predetermined voltage, and outputs the secondary power supply voltage V2 via the OUT terminal 32. The enable signal is a signal that is predetermined as a control signal for the general-purpose IC 13. The control signal here is a signal for controlling the operation and non-operation of the general-purpose IC 13, which is a power supply circuit. In other words, while the enable signal is provided to the general-purpose IC 13, the secondary power supply voltage V2 is continuously generated and output from the general-purpose IC 13. The enable signal can be, for example, a signal indicating a voltage equal to or greater than a predetermined magnitude (i.e., a high-level voltage).

When the supply of the enable signal starts, the general-purpose IC 13 executes a process known as a soft start. A soft start is a process that gradually increases the voltage output from the OUT terminal 32 from 0 V to a predetermined voltage (i.e., the secondary power supply voltage V2 in this case).

One end of the coil 17 is connected to the OUT terminal 32 of the general-purpose IC 13, and the other end is connected to a power input terminal (not shown) of the first microcomputer 11a. A capacitor 16 is connected between the other end of the coil 17 and ground. Furthermore, the other end of the coil 17 is connected to the ASIC 15 (i.e., the judgment terminal 65 described later). In other words, the output voltage from the general-purpose IC 13 is input to the judgment terminal 65.

In such a first ECU 11a, when the general-purpose IC 13 is driven by an enable signal, the output voltage from the general-purpose IC 13 is applied to the coil 17, the capacitor 16, the first microcomputer 11a, and the judgment terminal 65.

<ECU with ASIC connected to switching circuit>
As shown in FIG. 2, the second ECU 1 b includes a second microcomputer 11 b, a switching circuit 14, an ASIC 15, a coil 17, and a capacitor 16.

The second microcomputer 11b includes a CPU and memory (not shown), and the CPU of the second microcomputer 11b executes a program stored in the memory to realize at least some of the functions of the second ECU 1b. The second microcomputer 11b is driven by the supply of a secondary power supply voltage V2 (e.g., 1 V) generated by the switching circuit 14.

The switching circuit 14 includes a gate terminal 45, a gate terminal 46, and an output terminal 43 as terminals for connection to the outside of the switching circuit 14.
The switching circuit 14 is a so-called step-down switching regulator that generates a secondary power supply voltage V2 (e.g., 1 V) having a different voltage value from the primary power supply voltage V1 (e.g., 6 V) from the primary power supply voltage V1 and outputs the secondary power supply voltage V2 from the output terminal 43.

The switching circuit 14 includes two switching elements 41, 42 arranged in series between a power supply and ground. The power supply here is a power supply for operating the switching circuit 14, and specifically may be the voltage line 19 of the primary power supply voltage V1. The switching elements 41, 42 are elements that switch on and off according to a control signal, and may be, for example, MOSFETs.

Each of the switching elements 41 and 42 has a switching terminal to which a signal for switching on and off is input. The switching element 41 has a gate terminal 45 as a switching terminal, and the switching element 42 has a gate terminal 46 as a switching terminal. These switching terminals, such as the gate terminal 45 of the switching element 41 and the gate terminal 46 of the switching element 42, are also referred to as second control terminals.

The switching circuit 14 generates and outputs the secondary power supply voltage V2 when opposing predetermined signals (hereinafter also referred to as switching signals) are provided to these second control terminals (i.e., gate terminals 45, 46) as control signals for the switching circuit 14. The control signals here are signals for controlling the operation and non-operation of the switching circuit 14, which is a power supply circuit. In other words, while the switching signal is being supplied to the switching circuit 14, the secondary power supply voltage V2 is continuously generated and output from the switching circuit 14. The control signal for the switching circuit 14 is also referred to as the second control signal.

The opposing predetermined signals refer to, for example, a signal in which, when a signal of a level (hereinafter, high level) that turns on switching element 41 is given to gate terminal 45, a signal of a level (hereinafter, low level) that turns off switching element 42 is given to gate terminal 46. Also, for example, a signal in which, when a low level signal that turns off switching element 41 is given to gate terminal 45, a high level signal that turns on switching element 42 is given to gate terminal 46.

Here, a high-level signal is a voltage equal to or greater than a predetermined value that can turn on switching elements 41 and 42, and a low-level signal is a voltage less than a predetermined value that can turn off switching elements 41 and 42.

The output voltage output from the switching circuit 14 by switching the switching elements 41, 42 on and off is smoothed by the coil 17 and capacitor 16 described below. In other words, the switching circuit 14 adjusts the periods during which the switching elements 41, 42 are on and off by the second control signal, and controls the output voltage output from the output terminal 43 to be a predetermined secondary power supply voltage V2. As a result, the secondary power supply voltage V2, which has a voltage value different from the primary power supply voltage V1, is output from the output terminal 43.

For example, the drain side of the MOSFET of the switching element 41 is connected to the voltage line 19 of the primary power supply voltage V1, and the source side of the MOSFET is connected to the drain side of the MOSFET of the switching element 42. The source side of the MOSFET of the switching element 42 is connected to ground.

The output terminal 43 corresponds to the connection point between the switching element 41 (i.e., the source side) and the switching element 42 (i.e., the drain side), and is also connected to the LX terminal 63 of the ASIC 15. Note that, although an example using an N-type MOSFET has been described here, the switching elements 41 and 42 are not limited to N-type MOSFETs.

One end of the coil 17 is connected to the output terminal 43 of the switching circuit 14, and the other end is connected to a power input terminal (not shown) of the second microcomputer 11b. A capacitor 16 is connected between the other end of the coil 17 and ground. Furthermore, the other end of the coil 17 is connected to the ASIC 15 (i.e., the judgment terminal 65). In other words, the output voltage from the switching circuit 14 is input to the judgment terminal 65.

<ASIC Configuration>
The ASIC 15 includes a monitoring terminal 61, a VGH terminal 62, an LX terminal 63, a VGL terminal 64, and a determination terminal 65 as terminals for connecting to the outside of the ASIC 15. Hereinafter, the VGH terminal 62, the LX terminal 63, and the VGL terminal 64 are also particularly referred to as a connection terminal group.

The monitoring terminal 61 is connected to the voltage line 19 of the primary power supply voltage V1.
The VGH terminal 62, the LX terminal 63, and the VGL terminal 64 included in the group of connection terminals are connected to the general-purpose IC 13 (i.e., the ENA terminal 30) by a portion of the group of connection terminals (i.e., the VGL terminal 64), and are connected to the switching circuit 14 (i.e., the gate terminal 45, the output terminal 43, and the gate terminal 46) by all of the group of connection terminals (i.e., the VGH terminal 62, the LX terminal 63, and the VGL terminal 64).

The judgment terminal 65 is a terminal for acquiring an output voltage from an external circuit (that is, one of the general-purpose IC 13 and the switching circuit 14).
The ASIC 15 is realized by, for example, a circuit (i.e., hardware) that combines logic elements, etc. The ASIC 15 starts up, for example, when power (for example, a battery power supply voltage supplied from a vehicle battery, etc.) is applied to the ASIC 15.

The ASIC 15 has a primary power supply control unit (not shown), a primary power supply voltage monitoring unit 51, and a startup control unit 50 as functions realized by the ASIC 15. The startup control unit 50 has an output voltage monitoring unit 52, an external connection circuit determination unit 53, and an ASIC built-in power supply 54.

The above-mentioned primary power supply control unit controls a primary power supply generating unit (not shown) provided in the ECU 1. The primary power supply generating unit generates a primary power supply voltage V1 (e.g., 6 V) from a battery power supply voltage (e.g., 12 V) and outputs the primary power supply voltage V1 to a voltage line 19. When the supply of the battery power supply voltage to the ASIC 15 starts, the primary power supply control unit performs a soft start process to gradually increase the voltage value output by the primary power supply generating unit from 0 V to a predetermined primary power supply voltage value (i.e., 6 V).

For example, the primary power supply generating unit may be a so-called step-down switching regulator. That is, although not shown, the primary power supply generating unit may include, for example, a high-side MOSFET and a low-side MOSFET, a coil, and a capacitor provided between the battery power supply voltage and ground. The primary power supply control unit controls the high-side MOSFET and the low-side MOSFET to alternately turn on and off, causing the primary power supply generating unit to generate the primary power supply voltage V1.

The MOSFET of the primary power generation unit (not shown) controlled by the ASIC 15 reduces the battery power supply voltage (12 V) to a primary power supply voltage (6 V), and the gradual increase in the primary power supply voltage V1 is observed via the monitoring terminal 61. Note that in this embodiment, the battery power supply voltage is described as 12 V, but the battery power supply voltage is not limited to this.

The ASIC built-in power supply 54 includes an output control unit 55. The ASIC built-in power supply 54 also includes a driver 56 and a driver 57.
The driver 56 is controlled by the output control unit 55 and outputs a signal for turning on or off the switching element 41 , which is the high-side element of the switching circuit 14 , to a VGH terminal 62 .

The driver 57 is controlled by the output control unit 55 and outputs a signal to the VGL terminal 64 to turn on or off the switching element 42, which is the low-side element of the switching circuit 14.

When the switching circuit 14 is connected to the ASIC 15 as an external circuit, as shown in FIG. 2, the gate terminal 45 of the switching element 41, which is the high-side element of the switching circuit 14, is connected to the VGH terminal 62. Also, the gate terminal 46 of the switching element 42, which is the low-side element of the switching circuit 14, is connected to the VGL terminal 64. Also, the output terminal 43 is connected to the LX terminal 63.

In other words, the VGH terminal 62, the LX terminal 63, and the VGL terminal 64 as a group of connection terminals connected to the switching circuit 14 include a group of drive terminals (i.e., the VGH terminal 62, the VGL terminal 64) connected to the gate terminals 45, 46 as second control terminals.

When the ASIC 15 and the switching circuit 14 are connected, the drivers 56 and 57 are controlled by the output control unit 55 so that high-level signals are alternately output to the VGH terminal 62 and the VGL terminal 64. The high-level signals alternately output to the VGH terminal 62 and the VGL terminal 64 are the switching signals described above.

On the other hand, when the general-purpose IC 13 is connected to the ASIC 15 as an external circuit, the ENA terminal 30 of the general-purpose IC 13 is connected to the VGL terminal 64 as shown in FIG. 1. The VGL terminal 64 is also a terminal that outputs a signal for turning on or off the switching element 42, which is the low-side element of the switching circuit 14, when the switching circuit 14 is connected to the ASIC 15 as an external circuit. In other words, the VGL terminal 64 is used both as a terminal connected to the switching circuit 14 and as a terminal connected to the general-purpose IC 13.

When the ASIC 15 and general-purpose IC 13 are connected, the driver 57 is controlled by the output control unit 55 so that a high-level signal is output to the VGL terminal 64. This high-level signal output to the VGL terminal 64 is an enable signal. Note that the driver 56 does not operate (i.e., no signal is output from the output side) when the ASIC 15 and general-purpose IC 13 are connected.

[1-2. Processing]
<Processing performed by ASIC>
Next, the process executed by the ASIC 15 of this embodiment will be described with reference to the flowchart shown in Fig. 3. This process is started, for example, when the ASIC 15 is powered on (for example, a battery power supply voltage).

When power is applied to the ASIC 15, either the general-purpose IC 13 or the switching circuit 14 is already connected to the ASIC 15 as an external circuit. However, the ASIC 15 does not recognize which of the general-purpose IC 13 and the switching circuit 14 is connected.

The ASIC 15 first determines whether the general-purpose IC 13 or the switching circuit 14 is connected to the ASIC 15 as an external circuit, and then operates in a manner corresponding to the circuit determined to be connected between the general-purpose IC 13 and the switching circuit 14.

Specifically, in S10, the primary power supply voltage monitoring unit 51 in the ASIC 15 determines whether the voltage V _EN (i.e., primary power supply voltage V1) acquired at the monitoring terminal 61 has reached or exceeded a predetermined threshold (hereinafter, the startup threshold). As described above, the soft start process of the ASIC 15 causes the value of the primary power supply voltage V1 to rise gently from 0 V immediately after power is applied to the ASIC 15. For this reason, if the voltage V _EN observed (i.e., acquired) at the monitoring terminal 61 is less than the startup threshold, the primary power supply voltage monitoring unit 51 waits until it reaches or exceeds the startup threshold.

For example, the startup threshold can be set to a voltage value that is less than the steady-state value of the primary power supply voltage V1 and allows a supply destination of the primary power supply voltage V1 to operate correctly. The steady-state value of the primary power supply voltage V1 refers to the voltage value (i.e., 6 V) of the primary power supply voltage V1 after it has stabilized (i.e., in a steady state). Destinations of the primary power supply voltage include, for example, the general-purpose IC 13 and the switching circuit 14. When the voltage _VEN acquired at the monitoring terminal 61 becomes equal to or greater than the startup threshold, the primary power supply voltage monitoring unit 51 shifts the process to S20.

If it is determined that the voltage _VEN acquired at the monitoring terminal 61 is equal to or higher than the startup threshold, in S20, the primary power supply voltage monitoring unit 51 outputs a startup signal to the ASIC built-in power supply 54 (i.e., specifically, the output control unit 55).

When the primary power supply voltage monitoring unit 51 outputs a start signal, in S30, the ASIC built-in power supply 54 (i.e., the output control unit 55) outputs an identification signal from a specific terminal. In other words, the start signal is a signal that triggers the output of the identification signal from the specific terminal.

The specific terminal is a part (i.e., a predetermined one) of the above-mentioned group of connection terminals (i.e., the VGH terminal 62, the LX terminal 63, and the VGL terminal 64), and is also one of the above-mentioned group of drive terminals (i.e., the VGH terminal 62 and the VGL terminal 64). The specific terminal is a terminal that, when an identification signal is output from the specific terminal, causes the output voltage from the external circuit to differ depending on whether the general-purpose IC 13 is connected to the ASIC 15 as an external circuit or the switching circuit 14 is connected to the ASIC 15 as an external circuit. The identification signal is a signal for identifying whether the external circuit is the general-purpose IC 13 or the switching circuit 14.

In this embodiment, the specific terminal is the VGL terminal 64. The identification signal is a signal that indicates a high-level voltage (that is, V _GL =H).
In other words, the identification signal output from the VGL terminal 64, which is a specific terminal, is a signal that can become an enable signal when the general-purpose IC 13 is connected to the ASIC 15, and is also a signal that can become a signal that turns on the switching element 42, which is a low-side element, when the switching circuit 14 is connected to the ASIC 15.

Specifically, when the start signal is output, the output control unit 55 operates the driver 57 and causes the driver 57 to output a high-level voltage (i.e., V _GL =H) to the VGL terminal 64. As a result, from this step onwards, the driver 57 continues to output a high-level voltage from the VGL terminal 64. Note that in this step, the output control unit 55 does not operate the driver 56. The driver 56 is turned off, and the VGH terminal 62 is at a low level (i.e., V _GH =L).

When a high-level voltage (i.e., V _GL =H) is output as an identification signal from the VGL terminal 64, which is a specific terminal, in S40, the output voltage monitor 52 acquires (i.e., observes) the voltage V _MO of the determination terminal 65. As the voltage V _MO of the determination terminal 65, the output voltage from the power supply circuit (i.e., the general-purpose IC 13 or the switching circuit 14) connected to the ASIC 15 as an external circuit is observed.

When the output voltage monitor 52 acquires the voltage V _MO of the determination terminal 65, the external connection circuit determination unit 53 waits in S50 until the secondary power supply voltage V2 becomes stable (for example, until a predetermined stabilization time has elapsed). The stabilization time may be, for example, equal to or longer than the time required for the output voltage (i.e., the secondary power supply voltage V2) from the general-purpose IC 13 that may be connected to the ASIC 15 as an external circuit to become stable.

In other words, the external connection circuit determination unit 53 waits until the stabilization time has elapsed, which is the time it takes for the voltage V _MO acquired at the determination terminal 65 to go from 0 V to the steady-state value of the secondary power supply voltage V2 (i.e., 1 V) when the general-purpose IC 13 is connected to the ASIC 15.

Next, in S60, the external connection circuit determination unit 53 determines whether the voltage V _MO observed at the determination terminal 65 is equal to or greater than a predetermined voltage (hereinafter also referred to as a determination voltage). The determination voltage may be any predetermined voltage value that is equal to or less than the steady-state value (i.e., 1 V) of the secondary power supply voltage V2 and is relatively greater than 0 (i.e., not a value close to 0). The steady-state value of the secondary power supply voltage V2 refers to the voltage value (i.e., 1 V) of the secondary power supply voltage V2 after it has stabilized (i.e., during steady state). For example, the determination voltage may be a value equal to the steady-state value (i.e., 1 V) of the secondary power supply voltage V2. Note that "equal" here is not limited to "equal" in the strict sense, and may not be a value that is strictly "equal" as long as it has a similar effect.

Here, if the voltage V _MO acquired at the determination terminal 65 is equal to or higher than the determination voltage, the external connection circuit determination unit 53 shifts the process to S70.
In S70, the external connection circuit determination unit 53 determines that the external circuit connected to the ASIC 15 has a circuit configuration using the general-purpose IC 13.

When the external connection circuit determination unit 53 determines that the external circuit connected to the ASIC 15 is a general-purpose IC 13, in S80, the ASIC built-in power supply 54 (i.e., the output control unit 55) operates in the first mode and transitions to S110.

The first mode is a mode in which the general-purpose IC 13 is operated (i.e., driven). Specifically, the output control unit 55 causes the driver 57 to output an enable signal (i.e., a high-level voltage) to the VGL terminal 64 to drive the general-purpose IC 13, which is an external circuit. In other words, the output control unit 55 continues to output the high-level voltage that has been continuously output to the VGL terminal 64 since S30, even after S70, via the driver 57.

On the other hand, when the external connection circuit determination section 53 determines that the voltage V _MO acquired at the determination terminal 65 is less than the determination voltage (for example, 0 V), it shifts the process to S90.
In S90, the external connection circuit determination unit 53 determines that the external circuit connected to the ASIC 15 has a circuit configuration using the switching circuit 14, and moves the process to S100.

When the external connection circuit determination unit 53 determines that the external circuit connected to the ASIC 15 is the switching circuit 14, in S100, the ASIC built-in power supply 54 (i.e., the output control unit 55) operates in the second mode and the process proceeds to S110.

The second mode is a mode in which the switching circuit 14 is operated (i.e., driven). Specifically, the output control unit 55 causes the drivers 56 and 57 to output switching signals to the VGH terminal 62 and the VGL terminal 64 to drive the switching circuit 14, which is an external circuit.

As described above, the switching signal is a signal in which a high-level voltage is alternately output to the VGL terminal 64 and a high-level voltage is alternately output to the VGH terminal 62. In other words, instead of the high-level voltage that has been continuously output to the VGL terminal 64 since S30, from S70 onwards, a switching signal is output to alternately turn on and off the switching elements 41 and 42.

When the ASIC built-in power supply 54 starts driving the external circuit (i.e., the general-purpose IC 13 or the switching circuit 14) in a manner corresponding to the external circuit, in S110, the output voltage monitor 52 waits until it observes that the output voltage from the external circuit has stabilized at a predetermined voltage (e.g., the secondary power supply voltage V2). For example, the output voltage monitor 52 may determine that the output voltage from the external circuit (i.e., the secondary power supply voltage V2) has stabilized when the difference between the voltage acquired at the determination terminal 65 and the steady-state value of the secondary power supply voltage V2 (i.e., 1 V) is within a predetermined range. The predetermined range here may be, for example, a value near 0. With this, the ASIC 15 ends this process.

<Operation>
The operation of the ASIC 15 of this embodiment will be described with reference to FIG.
<When the general-purpose IC 13 is connected>
First, as shown in FIG. 1, a case where a circuit configuration using a general-purpose IC 13 (for example, the general-purpose IC 13, a coil 17, a capacitor 16, and a first microcomputer 11a) is connected to the outside of an ASIC 15 will be described.

As shown in FIG. 4, when the ASIC 15 is powered on at time t0, the voltage _VEN acquired at the monitoring terminal 61 gradually rises from 0 V to the steady-state value of the primary power supply voltage V1 (for example, 6 V).

At time t1, when the voltage _VEN observed at the monitoring terminal 61 becomes equal to or higher than the startup threshold, the primary power supply voltage monitoring unit 51 outputs a startup signal to the output control unit 55 of the ASIC built-in power supply 54. In response to the startup signal, the output control unit 55 outputs a high-level voltage from the VGL terminal 64 via the driver 57. However, the VGH terminal 62 is at a low level.

Since the general-purpose IC 13 is connected to the ASIC 15 as an external circuit, a high-level voltage is supplied to the ENA terminal 30, and the general-purpose IC 13 starts to operate. The general-purpose IC 13 steps down the primary power supply voltage V1 (e.g., 6 V) input from the IN terminal 31 to a predetermined secondary power supply voltage V2 (e.g., 1 V) and outputs it from the OUT terminal 32.

The general-purpose IC 13 is configured to execute a soft start process in the same way as the primary power supply generating unit described above, and it takes a certain amount of time (i.e., a delay) for the steady-state value (i.e., 1 V) of the secondary power supply voltage V2 to be output from the OUT terminal 32. For this reason, the ASIC 15 waits for the stabilization time as described above.

At time t2 when the stabilization time has elapsed, the general-purpose IC 13 outputs the steady-state value (i.e., 1 V) of the secondary power supply voltage V2. In other words, the voltage _VMO acquired at the determination terminal 65 becomes equal to or greater than the determination threshold value. This causes the external connection circuit determination unit 53 to determine that the external circuit connected to the ASIC 15 is the general-purpose IC 13.

When the external connection circuit determination unit 53 determines that the external circuit connected to the ASIC 15 is the general-purpose IC 13, the ASIC built-in power supply 54 operates in the first mode at time t3. That is, the output control unit 55 causes the driver 57 to continuously output a high-level voltage (i.e., an enable signal) from the VGL terminal 64 after time t3. As a result, the general-purpose IC 13 continues to output the secondary power supply voltage V2 (i.e., 1 V) even after time t3.

<When the switching circuit 14 is connected>
Next, a case where a circuit configuration using the switching circuit 14 (for example, the switching circuit 14, the coil 17, the capacitor 16, and the second microcomputer 11b) is connected to the outside of the ASIC 15 as shown in FIG. 2 will be described.

The operation from time t0 to time t1 shown in FIG. 4 is the same as that in the case where the general-purpose IC 13 is connected.
At time t1, when a start signal is output from the primary power supply voltage monitor 51 to the output control unit 55, the output control unit 55 outputs a high-level voltage from the VGL terminal 64 via the driver 57. The VGH terminal 62 is at a low level.

Since the switching circuit 14 is connected to the ASIC 15 as an external circuit, a high-level voltage is supplied to the gate terminal 46, and the switching element 42, which is the low-side element of the switching circuit 14, turns on. However, since the VGH terminal 62 is at a low level, the switching element 41, which is the high-side element of the switching circuit 14, is off. Therefore, unlike when the general-purpose IC 13 is connected, the voltage at the output terminal 43 is 0 V.

The ASIC 15 waits for the stabilization time in the same manner as when the general-purpose IC 13 is connected.
At time t2 when the stabilization time has elapsed, the voltage at the output terminal 43 remains at 0 V. In other words, the voltage V _MO acquired at the determination terminal 65 is less than the determination value. As a result, the external connection circuit determination unit 53 determines that the external circuit configuration connected to the ASIC 15 is the switching circuit 14.

When the external connection circuit determination unit 53 determines that the external circuit connected to the ASIC 15 is the switching circuit 14, the ASIC built-in power supply 54 operates in the second mode at time t3. That is, the ASIC 15 causes the drivers 56 and 57 to continuously output switching signals from the VGL terminal 64 and the VGH terminal 62 after time t3. As a result, the switching circuit 14 continues to output the steady-state value of the secondary power supply voltage V2 (i.e., 1 V) after time t4, for example.

At the start of output of the switching signal, the output control unit 55 controls the switching signal so that the output voltage from the switching circuit 14 gradually increases from 0 V to the steady-state value of the secondary power supply voltage V2 (i.e., 1 V). Since the output voltage from the switching circuit 14 is acquired at the judgment terminal 65, the output control unit 55 may, for example, perform feedback control based on the voltage _VMO acquired at the judgment terminal 65 to gradually increase the output voltage from the switching circuit 14.

[1-3. Effects]
According to the first embodiment described above in detail, the following effects are achieved.
(1a) The ASIC 15 includes a group of connection terminals, such as a VGH terminal 62, an LX terminal 63, and a VGL terminal 64. The VGL terminal 64, which is a terminal for connecting the general-purpose IC 13 to the ASIC 15, is also used as a terminal for connecting the switching circuit 14 to the ASIC 15 (i.e., the VGH terminal 62, the LX terminal 63, and the VGL terminal 64).

In the ASIC 15, the start-up control unit 50 operates in a manner according to the type of external circuit based on the output voltage from the external circuit when a high-level voltage, which is an identification signal, is output from the specific terminal, the VGL terminal 64. The start-up control unit 50 includes an output voltage monitoring unit 52, an external connection circuit determination unit 53, and an ASIC built-in power supply 54.

The ASIC 15 automatically switches to an operating mode (i.e., the first mode or the second mode) according to the type of external circuit based on the difference in the output voltage from the external circuit (i.e., the general-purpose IC 13 or the switching circuit 14) when a high-level voltage is output from the VGL terminal 64. Because it switches automatically, the ASIC 15 does not need to have a terminal for inputting a signal from the outside to switch the operating mode. Furthermore, the VGL terminal 64, which is a specific terminal, is also used as part of the terminal for connecting the switching circuit 14 to the ASIC 15, as described above.

In this way, in the ASIC 15 of this embodiment, the terminals used to connect the switching circuit 14 to the ASIC 15 can also be used for other purposes, such as connecting the general-purpose IC 13 and switching the operating mode, thereby reducing the number of terminals for connecting to the outside world.

For comparison, Figs. 7 and 8 show an ECU 9 (i.e., ECUs 9a and 9b) that includes an ASIC (hereinafter, Comparative Example 19) that is a comparative example different from ASIC 15. Comparative Example 19 further includes a V-ENA terminal 90 in addition to terminals (i.e., VGH terminal 62, LX terminal 63, and VGL terminal 64) that are used to connect the switching circuit 14. The V-ENA terminal 90 is a terminal that is used to connect Comparative Example 19 to the general-purpose IC 13. Comparative Example 19 also further includes a mode select terminal 91.

For example, in Comparative Example 19, as shown in FIG. 7, when a high-level (e.g., 5 V) signal is input from the mode select circuit 100 to the mode select terminal 91, the drive circuit selection unit 101 selects the general-purpose IC drive unit 102. The selected general-purpose IC drive unit 102 outputs an enable signal to the general-purpose IC 13 via the V-ENA terminal 90.

For example, in Comparative Example 19, as shown in FIG. 8, when a low-level (e.g., 0 V) signal is input from the mode select circuit 100 to the mode select terminal 91, the drive circuit selection unit 101 selects the ASIC built-in power supply unit 103. The selected ASIC built-in power supply unit 103 supplies a switching signal to the switching circuit 14 via the VGH terminal 62 and the VGL terminal 64.

In this way, in Comparative Example 19, which is connected to multiple types of external circuits, unlike the ASIC 15 of this embodiment, terminals are required for each application, such as connecting the general-purpose IC 13, connecting the switching circuit 14, and switching the operating mode.

In other words, the ASIC 15 of this embodiment serves multiple purposes for the terminals, and therefore does not require at least the V-ENA terminal 90 and the mode select terminal 91, as compared to Comparative Example 19. As a result, the ASIC 15 of this embodiment is able to reduce the number of terminals for connecting to an external circuit.

(1b) In the ASIC 15 of this embodiment, when a high-level voltage that is an identification signal is output from the VGL terminal 64 as a specific terminal, the ASIC 15 operates in the first mode if the voltage _V acquired at the determination terminal 65 is equal to or higher than the determination voltage, and operates in the second mode if the voltage _V acquired at the determination terminal 65 is less than the determination voltage.

As a result, the ASIC 15 outputs a high-level voltage only from the VGL terminal 64 and does not output a signal from the VGH terminal 62, so that the ASIC 15 can switch its operating mode depending on the difference in the output voltage from the external circuit and operate in a manner that corresponds to the external circuit.

(1c) In the ASIC 15 of this embodiment, the output voltage monitor 52 of the start-up control unit 50 acquires the output voltage from the external circuit connected to the ASIC 15 via the judgment terminal 65 when an identification signal is output from a specific terminal. The external connection circuit judgment unit 53 judges the type of the external circuit based on the fact that the output voltage when the identification signal is output is different when the external circuit connected to the ASIC 15 is the general-purpose IC 13 and when it is the switching circuit 14. In other words, it judges whether the external circuit is the general-purpose IC 13 or the switching circuit 14. The ASIC built-in power supply 54 operates in either the first mode or the second mode based on the judgment result.

This allows the ASIC 15 to determine the type of external circuit (i.e., power supply circuit), such as the general-purpose IC 13 or the switching circuit 14, by itself (i.e., automatically, without an external instruction signal). Then, based on the result of the determination, the ASIC 15 can operate by itself (i.e., automatically, without an external instruction signal) in a manner appropriate to the type of power supply circuit.

[1-4. Modifications]
<Modification 1-1>
In the ASIC 15 of the above embodiment, for example, when the external connection circuit determination unit 53 is configured by hardware, the ASIC 15 may be configured to execute a process in which S70 and S90 are deleted from the flowchart of Fig. 3. In other words, the ASIC 15 may switch the operation mode based on the voltage _VMO acquired at the determination terminal 65 without executing a process for identifying the type of external circuit connected to the ASIC 15.

In the above embodiment, the ASIC 15 corresponds to the integrated circuit, the ASIC built-in power supply 54 corresponds to the identification signal unit, the start-up control unit 50 corresponds to the start-up control unit, the general-purpose IC 13 corresponds to the first circuit, and the switching circuit 14 corresponds to the second circuit. The output voltage monitoring unit 52 corresponds to the acquisition unit, the external connection circuit determination unit 53 corresponds to the determination unit, and the ASIC built-in power supply 54 corresponds to the control execution unit. The VGH terminal 62, the LX terminal 63, and the VGL terminal 64 correspond to the connection terminal group, and the VGH terminal 62 and the VGL terminal 64 correspond to the drive terminal group.

The VGL terminal 64 corresponds to the specific terminal, and the high-level voltage output from the VGL terminal 64 corresponds to the identification signal. The ENA terminal 30 corresponds to the first control terminal. The switching element 41 and the switching element 42 correspond to the two switching elements, the gate terminal 45 corresponds to the switching terminal of the switching element 41, the gate terminal 46 corresponds to the switching terminal of the switching element 42, and the gate terminals 45 and 46 correspond to the second control terminal. S30 corresponds to the processing as the identification signal unit, and S80 and S100 correspond to the processing as the determination unit.

[2. Second embodiment]
[2-1. Configuration]
The second embodiment has a basic configuration similar to that of the first embodiment, and therefore differences will be described below. Note that the same reference numerals as those in the first embodiment indicate the same configurations, and the preceding description will be referred to.

In the first embodiment described above, a high-level signal was output as a specific signal from the VGL terminal 64 as a specific terminal, and the external circuit was controlled in a manner corresponding to the external circuit based on the output voltage from the external circuit. In contrast, the second embodiment differs from the first embodiment in that the VGH terminal 62 is used as the specific terminal.

[2-2. Processing]
<Processing by ASIC>
Next, the process executed by the ASIC 15 of the second embodiment in place of the process of the first embodiment (i.e., FIG. 3) will be described with reference to the flowchart of FIG. 5. Note that the processes of S10-S20, S40, and S70-S110 in FIG. 5 are similar to the processes of S10-S20, S40, and S70-S110 in FIG. 3, and therefore the description thereof will be partially simplified.

When the primary power supply voltage monitor 51 outputs a start-up signal, in S35, the ASIC built-in power supply 54 outputs an identification signal from a specific terminal. In this embodiment, the specific terminal is the VGH terminal 62. The identification signal is a signal indicating a high-level voltage (i.e., V _GH =H).
In other words, the identification signal output from the VGH terminal 62, which is a specific terminal, is a signal that can become a signal that turns on or off the switching element 41, which is a high-side element, when the switching circuit 14 is connected to the ASIC 15. The VGH terminal 62 is not used when the general-purpose IC 13 is connected to the ASIC 15. When the general-purpose IC 13 is connected to the ASIC 15, only the VGL terminal 64 is used.

Specifically, when the start signal is output, the output control unit 55 operates the driver 56, causing the driver 56 to output a high-level voltage (i.e., V _GH =H) to the VGH terminal 62. As a result, from this step onwards, the driver 56 continues to output a high-level voltage from the VGH terminal 62. Note that in this step, the output control unit 55 does not operate the driver 57. The driver 57 is turned off, and the VGL terminal 64 is at a low level (i.e., V _GL =L).

When the voltage V _MO of the determination terminal 65 is acquired by the output voltage monitor 52 in S40, the external connection circuit determination unit 53 waits in S55 until the primary power supply voltage V1 becomes stable (for example, until a predetermined stabilization time has elapsed). The stabilization time may be, for example, equal to or longer than the time required for the primary power supply voltage V1 controlled by the ASIC 15 to be stabilized to the primary power supply voltage (6 V) after the start-up threshold value of the primary power supply voltage V1 controlled by the ASIC 15 by the soft start process. Note that the stabilization time in this embodiment is shorter than the stabilization time required for the secondary power supply voltage V2 to be stabilized in the first embodiment.

Next, in S65, the external connection circuit determination unit 53 determines whether the voltage V _MO acquired at the determination terminal 65 is equal to or greater than a predetermined voltage (hereinafter also referred to as a determination voltage). In this embodiment, the determination voltage may be any predetermined voltage value that is equal to or less than the steady-state value of the primary power supply voltage V1 (i.e., 6 V) and is relatively greater than 0 (i.e., not a value close to 0). For example, the determination voltage may be a value equal to the steady-state value of the primary power supply voltage V1 (i.e., 6 V). Also, for example, the determination voltage may be a value equal to the steady-state value of the secondary power supply voltage V2 (i.e., 1 V).

Note that "equal" here is not limited to "equal" in the strict sense, and the values do not have to be strictly "equal" as long as the same effect is achieved. For example, the judgment voltage may be a value slightly smaller than the steady-state value of the primary power supply voltage V1. Or, the judgment voltage may be a value slightly smaller than the steady-state value of the secondary power supply voltage V2.

Here, when the voltage V _MO acquired at the judgment terminal 65 is less than the judgment voltage (for example, 0 V), the external connection circuit judgment unit 53 shifts the process to S70. After S70, the processes of S70, S80, and S110 are executed as in the first embodiment. Then, when the process of S110 is executed, this process ends. In other words, the external connection circuit judgment unit 53 judges that the external circuit connected to the ASIC 15 is a circuit configuration using the general-purpose IC 13, and the ASIC built-in power supply 54 switches the operation mode to operate in the first mode.

On the other hand, when the voltage V _MO acquired at the judgment terminal 65 is equal to or higher than the judgment voltage, the external connection circuit judgment unit 53 shifts the process to S90. After S90, the processes of S90, S100, and S110 are executed as in the first embodiment. Then, when the process of S110 is executed, this process ends. In other words, the external connection circuit judgment unit 53 judges that the external circuit connected to the ASIC 15 is a circuit configuration using the switching circuit 14, and the ASIC built-in power supply 54 switches the operation mode so as to operate in the second mode.

<Operation>
The operation of the ASIC 15 of this embodiment will be described with reference to FIG.
<When the general-purpose IC 13 is connected>
The operation from time t0 to time t1 is similar to that in the first embodiment.

At time t1, when the primary power supply voltage monitor 51 outputs a start signal to the output controller 55, the output controller 55 outputs a high-level voltage from the VGH terminal 62 via the driver 56. However, the VGL terminal 64 is at a low level.

Since the general-purpose IC 13 is connected to the ASIC 15 as an external circuit, the ENA terminal 30 connected to the VGL terminal 64 is at a low level, and the general-purpose IC 13 is not driven. The OUT terminal 32 is at a low level (i.e., 0 V), and the voltage _VMO acquired at the determination terminal 65 is also at a low level (i.e., 0 V).

The voltage _VEN observed at the monitoring terminal 61 gradually rises from 0V to the steady-state value of the primary power supply voltage V1 (i.e., 6V) due to the soft-start process of the ASIC 15. For example, at time t5 when the stabilization time has elapsed and the voltage _VEN observed at the monitoring terminal 61 has stabilized to the steady-state value of the primary power supply voltage V1 (i.e., 6V), the external connection circuit determination unit 53 determines whether the voltage _VMO acquired at the determination terminal 65 is equal to or higher than the determination voltage. Since the voltage _VMO acquired at the determination terminal 65 (i.e., 0V) is less than the determination voltage, the external connection circuit determination unit 53 determines that the external circuit connected to the ASIC 15 is the general-purpose IC 13.

When the external connection circuit determination unit 53 determines that the external circuit connected to the ASIC 15 is the general-purpose IC 13, at time t6, the ASIC built-in power supply 54 operates in the first mode. Note that since the general-purpose IC 13 is configured to execute a soft start process, it takes a certain amount of time for the steady-state value of the secondary power supply voltage V2, 1 V, to be output from the OUT terminal 32 (i.e., a certain delay occurs).

For example, at time t7, a certain amount of time after time t6, the general-purpose IC 13 outputs a steady-state value (i.e., 1 V) of the secondary power supply voltage V2. The general-purpose IC 13 continues to output the secondary power supply voltage V2 (i.e., 1 V) even after time t7.

<When the switching circuit 14 is connected>
The operation from time t0 to time t1 is similar to that in the first embodiment.
At time t1, when the primary power supply voltage monitoring unit 51 outputs a start signal to the output control unit 55, the output control unit 55 outputs a high-level voltage from the VGH terminal 62 via the driver 56. However, the VGL terminal 64 is at a low level.

Since the switching circuit 14 is connected to the ASIC 15 as an external circuit, a high-level voltage is supplied to the gate terminal 45, and the switching element 41, which is the high-side element of the switching circuit 14, is turned on. However, since the VGL terminal 64 is at a low level, the switching element 42, which is the low-side element of the switching circuit 14, is turned off. Therefore, the primary power supply voltage V1 (i.e., the primary power supply voltage V1 at time t1) that is gradually rising due to the soft start process of the ASIC 15 is output from the output terminal 43 of the switching circuit 14.

For example, at time t5 when the stabilization time has elapsed and the voltage _VEN observed at the monitoring terminal 61 has stabilized and reached the steady-state value of the primary power supply voltage V1 (i.e., 6 V), the external connection circuit determination unit 53 determines whether the voltage _VMO acquired at the determination terminal 65 is equal to or higher than the determination voltage. At this point, the voltage _VMO acquired at the determination terminal 65 is equal to or higher than the steady-state value of the primary power supply voltage V1 (i.e., 6 V). Since the voltage _VMO acquired at the determination terminal 65 (i.e., 6 V) is equal to or higher than the determination voltage, the external connection circuit determination unit 53 determines that the external circuit connected to the ASIC 15 is the switching circuit 14.

When the external connection circuit determination unit 53 determines that the external circuit connected to the ASIC 15 is the switching circuit 14, at time t6, the ASIC built-in power supply 54 operates in the second mode. Note that, when the output of the switching signal starts, the ASIC built-in power supply 54 (i.e., the output control unit 55) controls the switching signal so that the output voltage from the switching circuit 14 gradually drops from 6 V, which is the steady value of the primary power supply voltage V1, to 1 V, which is the steady value of the secondary power supply voltage V2.

For example, at time t7, a certain time after time t6, the steady-state value of the secondary power supply voltage V2 (i.e., 1 V) is output from the switching circuit 14. The steady-state value of the secondary power supply voltage V2 continues to be output from the switching circuit 14 even after time t7.

[2-3. Effects]
According to the second embodiment described above in detail, the same effects as the effects (1a) and (1c) of the first embodiment described above are achieved, and further, the following effect is achieved.

(2a) In the ASIC 15 of the present embodiment, when a high-level voltage that is an identification signal is output from the VGH terminal 62 serving as a specific terminal, if the voltage _V acquired at the determination terminal 65 is less than the determination voltage, the ASIC 15 operates in the first mode, and if the voltage V acquired at the determination terminal 65 is equal to or greater than the determination voltage, _{the ASIC 15} operates in the second mode.

As a result, the ASIC 15 outputs a high-level voltage only from the VGH terminal 62 and does not output a signal from the VGL terminal 64, so that the ASIC 15 can switch its operating mode depending on the difference in the output voltage from the external circuit and operate in a manner that corresponds to the external circuit.

[2-4. Modifications]
<Modification 2-1>
In a modification of the second embodiment, the ASIC 15 may be configured to execute the procedure by deleting S55 from the flowchart in Fig. 5. In other words, in this modification, the external connection circuit determination unit 53 in the ASIC 15 may determine whether the voltage V _OM of the determination terminal 65 is equal to or higher than the determination voltage immediately after acquiring the voltage V _OM of the determination terminal 65 in S40, without waiting until the output of the secondary power supply voltage V2 becomes stable in S55.

This is because, when the switching circuit 14 is connected to the ASIC 15, as soon as the output control section 55 outputs a signal indicating a high-level voltage, which is a specific signal, from the VGL terminal 64, which is a specific terminal, in response to a start-up signal, the primary power supply voltage V1 at this point in time is immediately obtained as the voltage V _OM of the determination terminal 65. Note that, when the general-purpose IC 13 is connected to the ASIC 15, 0 V is obtained as the voltage V _OM of the determination terminal 65 at this point in time.

That is, when the general-purpose IC 13 is connected to the ASIC 15 and when the switching circuit 14 is connected, the voltage outputted differs depending on the external circuit connected, so that the type of the external circuit can be determined based on the voltage V _OM of the determination terminal 65. The determination voltage may be, for example, a predetermined arbitrary voltage value that is equal to or less than the start-up threshold and relatively greater than 0 (i.e., not a value close to 0). For example, the determination voltage may be set to a value equal to the start-up threshold.

This makes it possible to quickly determine the type of external circuit without waiting until the stabilization time has elapsed, and quickly switch to an operation mode appropriate for the external circuit based on the determination result.
<Modification 2-2>
In the ASIC 15 of the above embodiment, for example, when the external connection circuit determination unit 53 is configured by hardware, the ASIC 15 may be configured to execute a process in which S70 and S90 are deleted from the flowchart of Fig. 5. In other words, the ASIC 15 may switch the operation mode based on the voltage _VMO acquired at the determination terminal 65 without executing a process for identifying the type of external circuit connected to the ASIC 15.

In the above embodiment, the VGH terminal 62 corresponds to a specific terminal, and the high-level voltage output from the VGH terminal 62 corresponds to a specific signal.
3. Other embodiments
Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments and can be implemented in various modified forms.

(3a) In the above-described embodiment, the ASIC 15 may be configured to continue to monitor the voltage V _MO acquired at the judging terminal 65 after switching the operation to operate in the first mode corresponding to the general-purpose IC 13, which is an external circuit. For example, the ASIC 15 may be configured to execute feedback control such as stopping the output of the enable signal when the voltage V _MO acquired at the judging terminal 65 is abnormal. The abnormality here means that the difference between the voltage V _MO acquired at the judging terminal 65 and the steady-state value (i.e., 1 V) of the secondary power voltage V2 is equal to or greater than a predetermined voltage threshold value.

Furthermore, in the above-described embodiment, the ASIC 15 may be configured to, after switching its operation to operate in the second mode according to the switching circuit 14, which is an external circuit, continue to monitor the voltage V _MO acquired at the determination terminal 65. For example, the ASIC 15 may be configured to execute feedback control, such as controlling the switching signal so that the voltage V _MO acquired at the determination terminal 65 is constant at the steady-state value of the secondary power voltage V2 (i.e., 1 V) regardless of fluctuations in the load of the ASIC 15 (e.g., the second microcomputer 11b, etc.).

The judgment terminal 65 is a terminal for acquiring the output voltage from an external circuit to determine the type of the external circuit, and can also be said to be a terminal for monitoring whether an external circuit such as the general-purpose IC 13 or the switching circuit 14 is normal or not. In other words, in the ASIC 15 of the above embodiment, the judgment terminal 65 can be used for multiple purposes, so that it is not necessary to have a terminal for each individual purpose. As a result, the above-mentioned ASIC 15 is able to reduce the number of terminals for connecting to an external circuit.

(3b) The ASIC 15 and the method described in the present disclosure may be realized by a dedicated computer provided by configuring a processor and a memory programmed to execute one or more functions embodied in a computer program. Alternatively, the ASIC 15 and the method described in the present disclosure may be realized by a dedicated computer provided by configuring a processor with one or more dedicated hardware logic circuits. Alternatively, the ASIC 15 and the method described in the present disclosure may be realized by one or more dedicated computers configured by combining a processor and a memory programmed to execute one or more functions with a processor configured with one or more hardware logic circuits. In addition, the computer program may be stored in a computer-readable non-transient tangible recording medium as instructions executed by a computer. The method for realizing the functions of each unit included in the ASIC 15 does not necessarily need to include software, and all of the functions may be realized using one or more hardware.

(3c) Multiple functions possessed by one component in the above embodiments may be realized by multiple components, or one function possessed by one component may be realized by multiple components. Also, multiple functions possessed by multiple components may be realized by one component, or one function realized by multiple components may be realized by one component. Also, part of the configuration of the above embodiments may be omitted. Also, at least part of the configuration of the above embodiments may be added to or substituted for the configuration of another of the above embodiments.

(3d) In addition to the ASIC 15 described above, the present disclosure can also be realized in various forms, such as an ECU or system that includes the ASIC 15 as a component, a program for causing the ASIC 15 to function, a non-transient physical recording medium such as a semiconductor memory on which the program is recorded, and a method for driving an external circuit connected to the ASIC 15.

1, 1a, 1b...ECU, 1a...first ECU, 1b...second ECU, 15...ASIC, 13...general-purpose IC, 14...switching circuit, 54...ASIC built-in power supply, 52...output voltage monitoring unit, 53...external connection circuit determination unit, 62...VGH terminal, 63...LX terminal, 64...VGL terminal, 65...determination terminal.

Claims (5)

An integrated circuit (15), comprising:
a connection terminal group (62, 63, 64) including a plurality of terminals, some of which are connected to a first circuit (13) and all of which are connected to a second circuit (14);
a determination terminal (65) that is an external circuit connected to the integrated circuit and that is used to acquire an output voltage from one of the first circuit and the second circuit;
an identification signal unit (54) configured to output the identification signal from a predetermined specific terminal among the group of connection terminals, the specific terminal having an output voltage different between a case where the first circuit is connected to the integrated circuit as the external circuit and a case where the second circuit is connected to the integrated circuit as the external circuit when a predetermined identification signal is output from the specific terminal;
a start-up control unit (50) configured to acquire the output voltage from the external circuit via the determination terminal when the identification signal is output, and to operate in either a first mode for driving the first circuit or a second mode for driving the second circuit based on the output voltage;
1. An integrated circuit comprising: 2. The integrated circuit of claim 1,
the first circuit is a power supply circuit configured to output a predetermined voltage in response to a first control signal, which is a predetermined control signal for the first circuit, being provided to a first control terminal (30) connected to an external device;
the second circuit is a power supply circuit configured to include two switching elements (41, 42) arranged in series between a power supply and ground, and to output a predetermined voltage having a voltage value different from that of the power supply by receiving a predetermined opposite second control signal as a control signal for the second circuit to a second control terminal (45, 46) which is a switching terminal provided in each of the switching elements;
In the integrated circuit,
the connection terminal group includes a drive terminal group (62, 64) connected to the second control terminal,
the terminal which is a part of the group of connection terminals and is connected to the first circuit is one of the group of drive terminals and is connected to the first control terminal. 3. An integrated circuit according to claim 2, comprising:
the specific terminal (64) is one of the group of drive terminals, and outputs a signal for turning on or off the switching element (42), which is a low-side element, when the second circuit is connected to the integrated circuit;
the start-up control unit operates in the first mode when the voltage acquired at the determination terminal is equal to or higher than a predetermined determination voltage when the identification signal is output from the specific terminal, and operates in the second mode when the voltage acquired at the determination terminal is lower than the determination voltage. 3. An integrated circuit according to claim 2, comprising:
the specific terminal (62) is one of the group of drive terminals, and outputs a signal for turning on or off the switching element (41), which is a high-side element, when the second circuit is connected to the integrated circuit;
the start-up control unit operates in the first mode when the voltage acquired at the determination terminal is less than a predetermined determination voltage when the identification signal is output from the specific terminal, and operates in the second mode when the voltage acquired at the determination terminal is equal to or greater than the determination voltage. An integrated circuit according to any one of claims 1 to 4,
The startup control unit is
an acquisition unit (52) configured to acquire the output voltage from the external circuit via the determination terminal when the identification signal is output;
a determination unit (53) configured to determine whether the external circuit connected to the integrated circuit is the first circuit or the second circuit based on the output voltage acquired by the acquisition unit;
a control execution unit (54) configured to operate in either the first mode or the second mode based on a result of the determination by the determination unit;
1. An integrated circuit comprising:

Images