JP7103848B2 - Semiconductor device and how to start the semiconductor device - Google Patents

Description

Application of Article 30, Paragraph 2 of the Patent Law On January 16, 2018, free samples were distributed at the customer offices of Lapis Semicondakuda Co., Ltd.

The present invention relates to a semiconductor device and a method of starting a semiconductor device.

In recent years, various devices using semiconductors are provided with a reference voltage generation circuit to generate a reference voltage obtained by stepping down the external voltage of an external power source. As an example of this reference voltage generation circuit, a bandgap reference (Band Gap) that forms a stable predetermined voltage based on a so-called bandgap voltage by using two unidirectional elements such as a diode in which a current flows in one direction. A Reference (BGR) circuit is known. Further, there is also known a technique of supplying a starting current to the differential stage of a reference voltage generating circuit using a differential amplifier that stabilizes a predetermined voltage based on the current difference flowing through each of the two unidirectional elements. .. For example, a technique of supplying a starting current to both differential stages of a bandgap reference circuit is known (see Patent Document 1).

JP-A-2002-151653

However, when a starting current is supplied to one of the differential stages of the bandgap reference circuit, the current difference applied to the differential stage becomes large due to variations in the elements during manufacturing, or until a stable predetermined voltage is reached. It may take some time to start up. Further, when the starting current is supplied to both of the differential stages of the bandgap reference circuit, there may be a problem similar to the case where the starting current is supplied to one of the differential stages due to the relationship between the supplied starting currents. Sometimes there is room for improvement in order to stabilize the operation in a short time.

An object of the present disclosure is to provide a semiconductor device and a method for starting the semiconductor device, which can stabilize the operation in a short time at the time of starting.

In order to achieve the above object, the first aspect of the semiconductor device of the present disclosure is
By supplying the first starting current, the first unidirectional element in which the first current flows in the first direction, and by supplying the second starting current different from the first starting current. A second unidirectional element through which a second current flows in a second direction is provided, and is predetermined based on the band gap voltage in each of the first unidirectional element and the second unidirectional element. A voltage generation circuit that generates a predetermined voltage and
A starting circuit that supplies different starting currents to each of the first unidirectional element and the second unidirectional element, and
A differential amplifier that outputs a start signal for starting the start circuit based on the current difference flowing through each of the first unidirectional element and the second unidirectional element.
With
The start circuit has a detection unit that detects that a start current is supplied to each of the first unidirectional element and the second unidirectional element based on the start signal, and detection of the detection unit. Based on the result, an output unit that outputs different starting currents to each of the first unidirectional element and the second unidirectional element is included.

The second aspect of the semiconductor device of the present disclosure is
By supplying the first starting current, the first unidirectional element in which the first current flows in the first direction, and by supplying the second starting current different from the first starting current. A second unidirectional element through which a second current flows in a second direction is provided, and is predetermined based on the band gap voltage in each of the first unidirectional element and the second unidirectional element. A voltage generation circuit that generates a predetermined voltage and
A starter circuit that supplies a starter current to a current generation circuit that generates a predetermined current, and a starter circuit that supplies the starter current.
A differential amplifier that outputs a start signal for starting the start circuit based on the current difference flowing through each of the first unidirectional element and the second unidirectional element.
To be equipped.

Further, the third aspect of the semiconductor device of the present disclosure is
A regulator element that outputs a predetermined voltage corresponding to the first voltage based on the difference between a predetermined first voltage and a second voltage different from the first voltage when the device is operated.
Using the current supplied from the current supply source, the first node forming the first voltage in the regulator element and the second voltage are formed so that the predetermined voltage is output from the regulator element. A starting circuit that supplies different starting currents to each of the second nodes,
To be equipped.

Further, the fourth aspect of the semiconductor device of the present disclosure is
The first voltage that forms the first voltage based on the difference between the first voltage determined by the supply current from the current source at the time of startup and the second voltage that is different from the first voltage that changes at the time of startup. A start circuit for supplying a different start current to each of the node and the second node forming the second voltage is provided.

Further, the method of starting the semiconductor device of the present disclosure is as follows.
By supplying the first starting current, the first unidirectional element in which the first current flows in the first direction, and by supplying the second starting current different from the first starting current. A second unidirectional element through which a second current flows in a second direction is provided, and is predetermined based on the band gap voltage in each of the first unidirectional element and the second unidirectional element. A voltage generating circuit that generates a predetermined voltage, a starting circuit that supplies different starting currents to each of the first unidirectional element and the second unidirectional element, the first unidirectional element, and the like. A method of starting a semiconductor device including a differential amplifier that outputs a start signal for starting the start circuit based on a current difference flowing through each of the second unidirectional elements.
The operation is started so that the output voltage reaches a predetermined predetermined voltage .
A state in which the output voltage has not reached the predetermined voltage is detected based on a first voltage determined by the supply current from the current supply source and a second voltage different from the first voltage that changes at startup . As a result, it is detected that the starting current is supplied to each of the first unidirectional element and the second unidirectional element.
Each of the first node forming the first voltage and the second node forming the second voltage so as to raise the voltage of the output node to a specified voltage in the unreachable state. By supplying different starting currents to, different starting currents are output to each of the first unidirectional element and the second unidirectional element .

According to the present disclosure, it is possible to improve the stability of operation at the time of startup in a short time.

FIG. 5 is a circuit diagram showing a configuration of an example of a bandgap reference circuit including a reference voltage generation circuit to which a semiconductor device is applied according to the first embodiment. It is a circuit diagram which shows the structure of the comparative example of the reference voltage generation circuit. It is a graph which shows an example of the voltage time characteristic of an output node at the time of startup. It is a flowchart which shows an example of the operation flow in the bandgap reference circuit which concerns on 1st Embodiment. FIG. 5 is a circuit diagram showing a configuration of an example of a reference current source circuit to which a semiconductor device is applied according to the second embodiment. It is a circuit diagram which shows the structure of the comparative example of the reference current source circuit. It is a graph which shows an example of the voltage time characteristic of an output node at the time of startup. It is a circuit diagram which shows the configuration of an example in which the connection destination of the start circuit which concerns on 3rd Embodiment is a voltage regulator. It is a circuit diagram which shows the structure of the 1st modification which concerns on 4th Embodiment. It is a circuit diagram which shows the structure of the 2nd modification which concerns on 4th Embodiment.

Hereinafter, embodiments will be described with reference to the drawings.
<First Embodiment>
In the first embodiment, the semiconductor device of the present disclosure is applied to a reference voltage generation circuit.

(Comparison example)
First, a comparative example 1 of a reference voltage generating circuit will be described prior to the description of the semiconductor device according to the first embodiment.

FIG. 2 shows an example of a circuit diagram of a bandgap reference (BGR) circuit 100 using a differential amplifier as a reference voltage generation circuit according to Comparative Example 1. The BGR circuit 100 generates a reference constant voltage by utilizing the fact that the voltage difference between the base and the emitter of two different bipolar transistors Q1 and Q2 becomes a constant voltage.

As shown in FIG. 2, the BGR circuit 100 includes a differential amplifier 110, a start-up circuit 120, bipolar transistors Q0 and Q1, epitaxial transistors MP0, MP1 and MPS, and a current source IST.

In this BGR circuit 100, the transistors Q1 and Q2 are in the form of a diode in which a base and a collector are commonly connected. The base and collector of transistors Q1 and Q2 are connected to the ground potential point Vss of the circuit. The emitter of the transistor Q0 is connected to the drain of the epitaxial transistor MP0 whose source is connected to the power potential point Vdd via the resistor R0. Further, the emitter of the transistor Q1 is connected to the drain of the transistor MP0 whose source is connected to the power supply voltage Vdd and the drain of the mirror-type epitaxial transistor MP1 via the resistor R1. The drain of the transistor MP1 and the resistor R0 are connected to the output node vbg. Further, a node vst0 is set between the emitter of the transistor Q0 and the resistor R0, and a node vst1 is set between the drain of the transistor MP1 and the resistor R1.

The differential amplifier 110 operates so that the voltages of the node vst0 and the node vst1 become a common voltage. Specifically, the differential amplifier 110 includes a ProLiant type transistors MP2, MP3, MP4, MP5, MP6 and an NMOS type transistors MN1, MN2, MN3, MN4. The transistors MP3 and MP4, the transistors MP5 and MP6, the transistors MN1 and MN2, and the transistors MN3 and MN4 are each connected in a current mirror form. The transistors MP5 and MP6, the transistors MN1 and MN2, and the transistors MN3 and MN4 are connected in series. Further, the sources of the transistors MP5 and MP6 are connected to the power supply potential point Vdd, and the drains of the transistors MN3 and MN4 are connected to the ground potential point Vss. The gate of the transistors MP5 and MP6 and the drain of the transistor MP5 are commonly connected to form a node vpgx. Further, the drain of the transistor MP6 is connected in common with the gates of the transistors MP0 and MP1 to form a node vpg. The sources of the transistors MP3 and MP4 are commonly connected and connected to the power potential point Vdd via the transistor MP2. Further, the gate of the transistor MP3 is connected to the node vst0, and the gate of the transistor MP4 is connected to the node vst1. Since the differential amplifier 110 has a well-known configuration, detailed description thereof will be omitted.

The activation circuit 120 operates so that the transistors Q0 and Q1 are activated. Specifically, the start-up circuit 120 is configured to include ProLiant-type transistors P0, P1, P2 and NMOS-type transistors N0, N1. The source of each of the mirror-type MIMO-type transistors P1 and P2 to which the gate is commonly connected is connected to the power potential point Vdd. The drain of the transistor P1 is connected to the gate of the transistor P0 whose source is connected to the power potential point Vdd, and the drain is connected to the source of the transistor N1 whose drain is connected to the ground potential point Vss. The drain of the transistor P0 is connected to the node vst0. The drain of the transistor P2 is connected to the gate of the transistor N1 and is connected to the source of the transistor N0 whose drain is connected to the ground potential point Vss. The gate of transistor N0 is connected to node vbg.

In the BGR circuit 100, the transistor N0 does not turn on (ON) unless the voltage of the output node vbg exceeds the threshold value (good fight value) of the transistor N0, and the starting current Ist0 flows through the transistor P0 to the transistor Q0 to start the transistor Q0. do. When the transistor Q0 is activated, the differential amplifier 110 detects the voltages of the node vst0 and the node vst1, a current flows through the transistor Q1, and the entire circuit starts operating.

On the other hand, when the voltage of the output node vbg exceeds the threshold value (good fighting value) of the transistor N0, the transistor N0 is turned on and the starting current Ist0 from the transistor P0 is stopped. In Comparative Example 1, the circuit configuration of the start circuit 120 has a wide variety of configurations, but the circuit method of detecting the output vbg is generally used.

By the way, the BGR circuit 100 of Comparative Example 1 has a problem that the voltage of the output node vbg causes overshoot at the time of startup.

FIG. 3 shows an example of voltage-time characteristics at the time of starting the reference voltage generation circuit.
In FIG. 3, the voltage-time characteristic in which the voltage of the output node vbg causes overshoot is shown by a alternate long and short dash line as the first task. Further, the voltage-time characteristic having an elapsed time until the voltage of the output node vbg rises to a specified voltage is shown by a two-dot chain line as a second problem.

That is, the first problem occurs due to the potential difference between the nodes vst0 and vst1 amplified by the differential amplifier 110. For example, when the starting current Ist0 is large due to manufacturing variations or the like, or when the transistor Q1 is difficult to turn on, the potential difference between the nodes vst0 and vst1 becomes large. Here, the differential amplifier 110 requires a sufficient gain in terms of the circuit configuration, and has, for example, an amplification factor of 60 dB to 80 dB. Therefore, the potential difference between the nodes vst0 and vst1 is amplified by the differential amplifier 110, and the voltage of the output node vbg causes overshoot. In particular, when the current that can be passed through the bipolar transistors Q0 and Q1 with low current consumption is on the order of nA, the overshoot that occurs is noticeable.

The second problem arises due to the influence of parasitic capacitance and leakage current at low current consumption. For example, the start circuit 120 is controlled by detecting the voltage level of the output node vbg by the threshold value (good fight value) of the transistor N0, but the threshold value (good fight value) also fluctuates due to the manufacturing variation, and the voltage of the output node vbg is low. When detected by the level and turned on, the start circuit 120 is stopped. Further, in the case of low current consumption, the influence of parasitic capacitance and leak current cannot be ignored, and the voltage of the output node vbg becomes high depending on the conditions such as the rise time of the power supply and the temperature, and the transistor N0 detects and starts the circuit 120. Stops. Therefore, the start circuit 120 is stopped before the voltage of the output node vbg rises to the specified voltage, or before the voltage of the output node vbg reaches the stable point of the entire circuit, and it takes time for the voltage of the output node vbg to rise. It will be necessary.

Therefore, in the first embodiment, a circuit capable of solving the first problem and the second problem, that is, at least a start circuit included in the reference voltage generation circuit is provided.

(Circuit configuration)
FIG. 1 shows an example of a circuit diagram of a BGR circuit 1 using a differential amplifier as a reference voltage generation circuit according to the first embodiment. In the BGR circuit 1 of the present disclosure, the same parts as those of the BGR circuit 100 shown in Comparative Example 1 are designated by the same reference numerals, and detailed description thereof will be omitted.

As shown in FIG. 1, the BGR circuit 1 according to the first embodiment includes a differential amplifier 10 having the same configuration as the BGR circuit 100, a starting circuit 20, bipolar transistors Q0 and Q1, and a ProLiant transistor. It includes MP0, MP1, MPS, and a current source IST.

The start-up circuit 20 includes a epitaxial transistor P0, P1, P2, P3 and a current source for supplying a reference current ISTUP. Transistors P0 and P1 have a mirror form in which gates are commonly connected, and their sources are connected to a power supply potential point Vdd. The drain of the transistor P0 is connected to the node vst0, and the drain of the transistor P1 is connected to the node vst1. The transistors P2 and P3 are connected in series, and the source of the transistor P2 is connected to the power potential point Vdd. On the other hand, the drain of the transistor P3 is connected to the ground potential point Vss via a current source that supplies the reference current ISTUP. The gate of transistor P2 is connected to node vpgx and the gate of transistor P3 is connected to node vpg. The transistors P2 and P3 and the current source for supplying the reference current ISTUP form a detection unit 22. Further, the transistor P0 in which the starting current Ist0 is passed through the transistor Q0 and the transistor P1 in which the starting current Ist1 is passed through the transistor Q1 constitute an output unit 24. Since there are various and general configurations of the current source for supplying the reference current ISTUP, such as using resistors and transistors, detailed description thereof will be omitted.

(Circuit operation)
At startup, the differential amplifier 10 operates to lower (or lower) the voltages of the nodes vpg and vpgx in order to raise (or lower) the voltage of the output node vbg to a specified voltage. In the following description, a case where the voltage of the output node vbg is raised to a specified voltage and the voltages of the nodes vpg and vpgx are lowered will be described. By the operation of the differential amplifier 10, the transistors P2 and P3 connected to the nodes vpg and vpgx are turned off, and the starting current Ist0 flows through the transistor P0 to the transistor Q0. Similarly, the starting current Ist1 flows through the transistor P1 to the transistor Q1. As a result, the entire circuit of the BGR circuit 1 starts operating.

When the voltage of the output node vbg exceeds the specified voltage, the voltage of the nodes vpg and vpgx reaches the voltage that becomes the stable point of the entire circuit. This voltage is the threshold value (good fight value) of the transistors P2 and P3, and the transistors P2 and P3 are turned on to stop the supply of the starting current Ist0 by the transistor P0 and the supply of the starting current Ist1 by the transistor P1.

By supplying the starting currents Ist0 and Ist1 to the transistors Q0 and Q1, respectively, it is possible to suppress an increase in the potential difference between the nodes vpg and vpgx at the time of starting, which is the first problem described above, and the voltage of the output node vbg overshoots. It can be suppressed from occurring.

Here, the current ratios of the transistors Q0 and Q1 in the BGR circuit 1 are represented by the following equation (1).
Q0 <Q1 ... (1)
When the current ratios of the transistors Q0 and Q1 conform to the equation (1), the relationship between the starting currents Ist0 and Ist1 is expressed by the following equation (2).
Ist0 ≤ Ist1 ・ ・ ・ (2)

When the starting current Ist0 is larger than the starting current Ist1, the potentials of the nodes vpg and vpgx are reversed, the stability point of the entire circuit of the BGR circuit 1 is disrupted, and the differential amplifier 10 is amplified to cause overshoot. , (1), and (2) are preferably operated under the conditions conforming to the above-mentioned equations (1) and (2). In this way, making the starting current Ist1 larger than the starting current Ist0 makes the voltage of the transistor P1 forming the starting current Ist1 flowing through the transistor Q1 larger than the voltage of the transistor P0 forming the starting current Ist0 flowing through the transistor Q0. Corresponding to different voltage ratios.

In this way, by connecting the transistors P2 and P3 of the detection unit 22 included in the start circuit 20 to the nodes vpg and vpgx of the differential amplifier 10, the start circuit 20 causes the start circuit 20 to reach a specified voltage until the voltage of the output node vbg reaches a specified voltage. Operate.

As a result, the start circuit 20 stops at a low level of the voltage of the output node vbg, which is the first problem, and the voltage of the output node vbg, which is the second problem, is a stable point of the entire circuit of the BGR circuit 1. It becomes possible to suppress the start circuit 20 from stopping before reaching.

Further, since the voltages of the nodes vpg and vpgx are undefined when the BGR circuit 1 is started, even if one of the voltages exceeds the threshold value (good fight value) of the transistors P2 and P3 of the detection unit 22, the other is Since it is off, the start circuit 20 does not stop.

That is, the start circuit 20 is stopped when the following conditions are met.
(Stop condition)
-The voltage of the output node vbg is the specified voltage.-The entire circuit has reached the stable point.-The voltage of the differential amplifier nodes vpg and vpgx is the stable voltage at which equations (1) and (2) hold. Therefore, the stability at startup is improved as compared with Comparative Example 1 described above.

In this way, the transistors P2 and P3 of the detection unit 22 included in the start circuit 20 are connected to the nodes vpg and vpgx of the differential amplifier 10, and the start circuit 20 is operated until the voltage of the output node vbg reaches a specified voltage. .. As a result, it is possible to prevent the start-up circuit 20 from stopping in at least one of a state in which the voltage of the output node vbg is at a low level and a state in which the voltage of the output node vbg is in a state before reaching the stable point of the entire circuit.

The BGR circuit 1 as the semiconductor device described above determines the difference between the first voltage determined by the supply current from the current supply source at the time of startup and the second voltage different from the first voltage that changes at the time of startup. Based on the detection and the detection result, it operates to supply different starting currents to each of the first node forming the first voltage and the second node forming the second voltage.

(Flow of operation of BGR circuit)
Next, the BGR circuit 1 will be further described with reference to a flowchart showing an operation flow. When the power is turned on, the BGR circuit 1 operates according to the processing of the flowchart shown in FIG. 4 as an example.

At startup, the BGR circuit 1 as a semiconductor device first starts operation in step S100 so that the output voltage reaches a specified voltage. Specifically, in order to raise the voltage of the output node vbg to a specified voltage, the differential amplifier 10 operates so as to lower the voltage of the nodes vpg and vpgx.

Next, the BGR circuit 1 operates the entire circuit in response to the operation of the differential amplifier 10. In this case, the start-up circuit 20 operates so that the start-up current at the time of start-up flows through the transistors Q1 and Q2 when the voltage of the output node vbg has not risen to the specified voltage. Specifically, in step S102, the detection unit 22 detects an unreachable state in which the voltage of the output node vbg has not risen to a specified voltage. The detection unit 22 determines in step S104 whether or not the state has not been reached. In the case of an affirmative determination, in step S106, the output unit 24 supplies a starting current, and in the case of a negative determination, in step S108. The supply of starting current is stopped. That is, the supply of the starting currents Ist0 and Ist1 by the starting circuit 20 is executed until the voltage of the output node vbg exceeds the specified voltage. Specifically, in the unreachable state, the transistors P2 and P3 connected to the nodes vpg and vpgx are turned off. When the transistors P2 and P3 are turned off, the starting current Ist0 flows through the transistor P0 to the transistor Q0, and the starting current Ist1 flows through the transistor P1 through the transistor Q1.

At this time, the start circuit 20 supplies the start currents Ist0 and Ist1 to the nodes vst0 and vst1 at a predetermined current ratio. That is, when the starting current Ist0 supplied by the starting circuit 20 is larger than the starting current Ist1, the potentials of the nodes vpg and vpgx are reversed, the stability point of the entire circuit of the BGR circuit 1 is disrupted, and the differential amplifier 10 is amplified. Causes overshoot. Therefore, the start circuit 20 supplies the start currents Ist0 and Ist1 to the nodes vst0 and vst1 in the relationship of the start currents Ist0 and Ist1 (Ist0 ≦ Ist1) according to the current ratio (Q0 <Q1) of the transistors Q0 and Q1. do.

On the other hand, when the voltage of the output node vbg exceeds the specified voltage, the voltages of the nodes vpg and vpgx reach the voltage that becomes the stable point of the entire circuit. This voltage is the threshold value (good fight value) of the transistors P2 and P3, and the transistors P2 and P3 are turned on to stop the supply of the starting current Ist0 by the transistor P0 and the supply of the starting current Ist1 by the transistor P1.

As described above, in the BGR circuit 1 according to the first embodiment, at the time of starting, the relationship between the starting currents Ist0 and Ist1 according to the current ratio (Q0 <Q1) of the transistors Q0 and Q1 to each of the transistors Q0 and Q1. By supplying the starting currents Ist0 and Ist1 in (Ist0≤Ist1), it is possible to suppress an increase in the potential difference between the nodes vpg and vpgx generated at the time of starting, and it is possible to suppress the voltage of the output node vbg from causing overshoot. can. Further, it is possible to prevent the start circuit 20 from stopping at a low level of the voltage of the output node vbg, and to prevent the start circuit 20 from stopping before the voltage of the output node vbg reaches the stable point of the entire circuit.

In the BGR circuit 1 according to the first embodiment, the embodiment including the bipolar transistors Q0 and Q1 has been described, but the present invention is not limited to this embodiment, and a diode element may be used.

<Second Embodiment>
In the second embodiment, the semiconductor device of the present disclosure is applied to a reference current source circuit (hereinafter, referred to as a bias circuit). That is, in the second embodiment, the semiconductor device of the present disclosure is applied to the starting circuit of the bias circuit.

(Circuit configuration)
FIG. 5 shows an example of a circuit diagram of the bias circuit 2 according to the second embodiment. Since the bias circuit 2 has the same configuration as the BGR circuit 1 shown in FIG. 1, the same parts are designated by the same reference numerals and detailed description thereof will be omitted.

As shown in FIG. 5, the bias circuit 2 according to the second embodiment includes a differential amplifier 10 having the same configuration as the BGR circuit 100, a starting circuit 20A, bipolar transistors Q0 and Q1, and a epitaxial transistor. It includes MP0 and MP1, ProLiant type transistors P1 and P2, and NMOS type transistors N2 and N3.

The transistors P1 and P2 constituting the bias circuit 2 have a mirror form in which gates are commonly connected, and their sources are connected to the power supply potential point Vdd. The drain of the transistor P1 is a node vp and is connected to the power potential point Vdd via an NMOS-type transistor N2 and a resistor R3. The node bp is also connected to the gate of the transistor MP2 included in the differential amplifier 10. The drain of the transistor P2 is a node vn and is connected to a power potential point Vdd via an NMOS-type transistor N3. The transistors N2 and N3 have a mirror form in which the gates are commonly connected, and are also connected to the node vn. Since the bias circuit has a general configuration, detailed description thereof will be omitted.

The start-up circuit 20A includes a epitaxial transistor P4 and P5 and a current source for supplying a reference current ISTUP. The transistors P4 and P5 are connected in series, and the source of the transistor P4 is connected to the power potential point Vdd. On the other hand, the drain of the transistor P5 is connected to the ground potential point Vss via a current source that supplies the reference current ISTUP. Further, the drain of the transistor P4 is a node vs. is connected to the gate of the transistor P0 for supplying the starting current to the node vn of the bias circuit. The source of the transistor P0 is connected to the power potential point Vdd, and the drain of the transistor P0 is connected to the node vn. The transistors P4 and P5 and the current source for supplying the reference current ISTUP form a detection unit 22A. Further, the transistor P0 for supplying the starting current to the node vn constitutes an output unit 24A.

(Circuit operation)
At startup, the circuit current does not flow through the bandgap reference unless the bias circuit is started.
No current flows in the transistor P4 connected to the node vpgx and the transistor P5 connected to the node vpg, the potential of the node vs is lowered by the reference current ISTUP, the transistor P0 is turned on, the starting current flows in the node vn, and the bias The circuit starts.

When the bias circuit is activated, the circuit current of the bandgap reference also increases, and when the specified current is reached, the currents of the transistors P4 and P5 also increase, the potential of the node vs. is raised, the transistor P0 is turned off, and the activation circuit 20A is stopped. ..

Further, since the voltages of the bandgap reference nodes vpg and vpgx are undefined at the time of startup, if the voltage of either one is equal to or less than the threshold value (good fight value) of the transistors P4 and P5 of the detection unit 22A, the startup circuit 20A Never stops.

(Comparative Example 2)
Here, a comparative example 2 of a general bias circuit and a start circuit will be described.
FIG. 6 shows an example of a circuit diagram of the bias circuit and the start circuit according to Comparative Example 2. The bias circuit 200 according to Comparative Example 2 includes transistors P1, P2, N2, N3 and a resistor R3, similarly to the bias circuit 2. Further, the start circuit 220 includes transistors P0 and P4 and a current source for supplying a reference current ISTUP. The gate of the transistor P4 is connected to the node vp, and the drain of the transistor P4 is connected to the node vn.

In the bias circuit 200 according to Comparative Example 2, the start circuit 220 operates according to the threshold value (good fight value) of the transistor P4, but the threshold value (good fight value) of the transistor P4 also fluctuates due to manufacturing variations, and the transistor P4 is turned off at a low level. It may take some time for the bias current of the bias circuit 200 to reach a specified current value.

FIG. 7 shows an example of the voltage-time characteristics when the bias circuit is started.
In FIG. 7, the voltage-time characteristic in which it takes time for the bias current to reach a specified current value is shown by a chain double-dashed line as a third task. In particular, when the current consumption is on the order of nA, this third problem appears remarkably. On the other hand, the voltage-time characteristics of the bias circuit 2 according to the second embodiment are shown by solid lines.

As can be understood from FIG. 7, in the bias circuit 2 according to the second embodiment, since the detection unit 22A of the start circuit of the bias circuit is connected to the bandgap reference, the bias circuit 2 according to the second embodiment is compared with the bias circuit 200 according to the comparative example 2. You can start up faster.

<Third Embodiment>
In the third embodiment, the semiconductor device of the present disclosure is applied to a voltage regulator. A voltage regulator is an integrated circuit that outputs a predetermined voltage even if the input voltage and output current change.

FIG. 8 shows an example of a circuit diagram in which the connection destination of the start circuit of the present disclosure according to the third embodiment is a voltage regulator. That is, in the third embodiment, the connection destination of the start circuit is a voltage regulator circuit instead of the BGR circuit. In the third embodiment, the same parts as those in the above embodiment are designated by the same reference numerals, and detailed description thereof will be omitted. again,

As shown in FIG. 8, the voltage regulator circuit 3 according to the third embodiment includes a start circuit 20B having the same configuration as the start circuit 20A shown in FIG. That is, the activation circuit 20B according to the third embodiment includes a detection unit 22B having the same configuration as the detection unit 22A of the activation circuit 20A shown in FIG. 5, and an output unit 24B having the same configuration as the output unit 24A.

(Circuit operation)
At startup, the circuit current does not flow in the voltage regulator circuit unless the bias circuit is started. No current flows in the transistor P4 connected to the node vpgx and the transistor P5 connected to the node vpg, the potential of the node vs is lowered by the reference current ISTUP, the transistor P0 is turned on, the starting current flows in the node vn, and the bias The circuit starts.

When the bias circuit is activated, the circuit current of the voltage regulator circuit also increases, and when the specified current is reached, the currents of the transistors P4 and P5 also increase, the potential of the node vs. is raised, the transistor P0 is turned off, and the activation circuit 20B is stopped. .. Further, since the voltages of the bandgap reference nodes vpg and vpgx are undefined at the time of startup, if the voltage of either one is equal to or less than the threshold value (good fight value) of the transistors P4 and P5 of the detection unit 22A, the startup circuit 20B Never stops.

<Fourth Embodiment>
The fourth embodiment is a modification of the second embodiment.
FIG. 9 shows a first modification according to the fourth embodiment, and FIG. 10 shows a second modification.
The activation circuit 20C of the first modification shown in FIG. 9 is different in that the connection destination of the gate of the transistor P5 in the activation circuit 20A shown in FIG. 5 is replaced with the node vpg and the detection unit 22C is the node vp. Even when the configuration is based on the activation circuit 20C of the first modification shown in FIG. 9, the same effect as that of the second embodiment is obtained.

Further, the start circuit 20D of the second modification shown in FIG. 10 detects a configuration in which the epitaxial type transistor P6 is further connected in series to the transistors P4 and P5 constituting the detection unit 22A in the start circuit 20A shown in FIG. The difference is that the part 22D is used. Even when the configuration is based on the activation circuit 20D of the second modification shown in FIG. 10, the same effect as that of the second embodiment is obtained.

In each of the above-described embodiments of the semiconductor device of the present disclosure, a mode including a differential amplifier, a reference voltage source circuit, a reference current source circuit, and a voltage regulator circuit has been described, but the present invention is not limited to this mode, and the differential amplifier is not limited to this mode. , A part or all of a reference voltage source circuit, a reference current source circuit, and a voltage regulator circuit may be used as an external element.

Further, the starting circuit described in each of the above embodiments can be configured in combination with the starting circuit shown in FIG.

It goes without saying that the configuration and operation of the circuit related to the semiconductor device of the present disclosure described in each of the above embodiments is an example, and can be changed depending on the situation within a range not deviating from the gist of the present disclosure. do not have.

1 Bandgap reference circuit (reference voltage generation circuit)
2 Bias circuit (reference current source circuit)
3 Voltage regulator circuit 10 Differential amplifier 20 Start circuit 22 Detector 24 Output part ISTUP Reference current Ist0 Start current Ist1 Start current N0, N1, N2, N3 Transistors P0, P1, P2, P3, P4, P4, P5, P6 Transistors Q0, Q1 Transistor Vdd Power supply potential point Vss Ground potential point vbg, vn, vp, vpg, vpgx, vs, vst0, vst1 node

Claims (7)

By supplying the first starting current, the first unidirectional element in which the first current flows in the first direction, and by supplying the second starting current different from the first starting current. A second unidirectional element through which a second current flows in a second direction is provided, and is predetermined based on the band gap voltage in each of the first unidirectional element and the second unidirectional element. A voltage generation circuit that generates a predetermined voltage and
A starting circuit that supplies different starting currents to each of the first unidirectional element and the second unidirectional element, and
A differential amplifier that outputs a start signal for starting the start circuit based on the current difference flowing through each of the first unidirectional element and the second unidirectional element.
With
The starting circuit is
A detection unit that detects that a starting current is supplied to each of the first unidirectional element and the second unidirectional element based on the start signal.
A semiconductor device including an output unit that outputs different starting currents to each of the first unidirectional element and the second unidirectional element based on the detection result of the detection unit. The first unidirectional element is connected to a node that generates the predetermined voltage, and the current density of the current flowing through the first unidirectional element is such that the current flowing through the second unidirectional element is increased. If the current density is high
The starting circuit is
The semiconductor device according to claim 1, wherein the first starting current supplied to the first unidirectional element is made smaller than the second starting current supplied to the second unidirectional element. The detection unit included in the start circuit is formed by connecting a first transistor element, a second transistor element, and a current source in series.
The semiconductor device according to claim 1 or 2. By supplying the first starting current, the first unidirectional element in which the first current flows in the first direction, and by supplying the second starting current different from the first starting current. A second unidirectional element through which a second current flows in a second direction is provided, and is predetermined based on the band gap voltage in each of the first unidirectional element and the second unidirectional element. A voltage generation circuit that generates a predetermined voltage and
A starter circuit that supplies a starter current to a current generation circuit that generates a predetermined current, and a starter circuit that supplies the starter current.
A differential amplifier that outputs a start signal for starting the start circuit based on the current difference flowing through each of the first unidirectional element and the second unidirectional element.
Semiconductor device equipped with . The starting circuit is
A detector that detects that a start-up current is supplied to the current generation circuit based on the start-up signal,
Includes an output unit that outputs a starting current to the current generation circuit based on the detection result of the detection unit.
The semiconductor device according to claim 4 . The semiconductor device according to claim 5, wherein the detection unit included in the start circuit is formed by connecting a first transistor element, a second transistor element, and a current source in series . By supplying the first starting current, the first unidirectional element in which the first current flows in the first direction, and by supplying the second starting current different from the first starting current. A second unidirectional element through which a second current flows in a second direction is provided, and is predetermined based on the band gap voltage in each of the first unidirectional element and the second unidirectional element. A voltage generation circuit that generates a predetermined voltage and
A starting circuit that supplies different starting currents to each of the first unidirectional element and the second unidirectional element, and
A differential amplifier that outputs a start signal for starting the start circuit based on the current difference flowing through each of the first unidirectional element and the second unidirectional element.
It is a method of starting a semiconductor device equipped with
The operation is started so that the output voltage reaches a predetermined predetermined voltage.
A state in which the output voltage has not reached the predetermined voltage is detected based on a first voltage determined by the supply current from the current supply source and a second voltage different from the first voltage that changes at startup. As a result, it is detected that a starting current is supplied to each of the first unidirectional element and the second unidirectional element.
Each of the first node forming the first voltage and the second node forming the second voltage so as to raise the voltage of the output node to a specified voltage in the unreachable state. By supplying different starting currents to, different starting currents are output to each of the first unidirectional element and the second unidirectional element.
How to start a semiconductor device.

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