JP3282666B2 - Electronics - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to electronic equipment, and more particularly to electronic equipment having a microcomputer.

[0002]

2. Description of the Related Art In a conventional electronic device, for example, a portable radio, when a wide temperature type (a type usable in a wide temperature range) LCD (liquid crystal display) is used as a display, a driving voltage of 5 V is required. The microcomputer for directly driving the microcomputer (hereinafter referred to as a microcomputer) also needs to have a 5V specification. FIG. 4 is a block diagram showing a configuration example of such a portable radio.

In FIG. 4, 1 is a power supply, 2 is DC / DC
Converter, 3 for microcomputer, 4 for tuner, 5 for LC
D and 6 are operation key circuits. The operation key circuit 6 is DC
It comprises resistors R1 to R5 and an operation key Sa connected in series between the output terminal of the / DC converter 2 and the ground, and operation keys Sb, Sc and Sd connected between a connection point of each resistor and the ground. . The DC / DC converter 2 boosts the DC voltage of the power supply 1 from 3 volts to 5 volts and outputs the same. The microcomputer 3 is driven by the output voltage of the DC / DC converter 2 of 5 V, and includes a key input port (A / D port) P2 and an output port connected to the tuner 4 and the LCD 5.

The respective operation keys Sa to Sd of the operation key circuit 6
Is turned on, the microcomputer 3 controls each part of the portable radio according to the value obtained by A / D converting the voltage value input to the key input port P2. In this example, the power source 1 of the portable radio is, for example, driven by two 1.5-volt batteries.

[0005]

However, in the configuration of FIG. 4, since each operation key is installed at various places in the design of the radio set, a signal line for the operation key becomes long (for example, a printed circuit board). The routing of the upper pattern becomes longer), and DC /
In some cases, noise from the DC converter 2 or the like gets on and interferes with various parts of the radio, resulting in poor performance.

An object of the present invention is to provide an electronic device which solves the above-mentioned conventional problems.

[0007]

According to a first aspect of the present invention, there is provided an electronic apparatus comprising: a DC power supply; and a microcomputer which is operated by being supplied with the DC power through a DC voltage conversion circuit. An electronic device having an operation key circuit including at least one operation key connected to the DC power supply and supplying a different voltage to a key input port of the microcomputer when each operation key is operated, wherein the key input port has It is characterized by determining which operation key has been operated based on the supplied input voltage.

[0008] Further, an electronic apparatus according to the present invention is characterized in that:
As described in the above, in an electronic device having a DC power supply and a microcomputer to which the DC power supply is supplied and operated via a DC voltage conversion circuit, the electronic device includes at least one operation key connected to the DC power supply. An operation key circuit for supplying a different voltage to the key input port of the microcomputer when the operation key is turned on, and a power supply detection input port for supplying the voltage of the DC power supply to the microcomputer as a reference voltage, the microcomputer comprising: It is characterized in that which operation key is operated is determined by a ratio between an input voltage supplied to the key input port and a reference voltage supplied to the power detection input port.

An electronic device according to the present invention is characterized in that:
As described in the above, in an electronic device having a DC power supply, and a microcomputer that is operated by being supplied with the DC power supply through a DC voltage conversion circuit, the electronic device is connected to the DC power supply, and connected to an input port of the microcomputer. A control circuit for supplying an output; and a power detection input port for supplying a voltage of the DC power supply as a reference voltage to the microcomputer, wherein the microcomputer has an input voltage supplied to the input port and the power detection input. The output value of the control circuit is determined based on a ratio of a reference voltage supplied to the port.

[0010]

FIG. 1 is a block diagram showing one embodiment of an electronic apparatus according to the present invention. The configuration of FIG.
Is the same as the configuration of FIG.
The difference is that the C / DC converter 2 is connected to the power supply 1 instead of the output terminal.

In the configuration of FIG. 1, since the power supply of the microcomputer 3 and the power supply of the operation key circuit 6 are separated, there is no restriction on the installation location of the operation keys, and interference from power supply noise is reduced.

[0012]

FIG. 2 is a block diagram showing another embodiment of the electronic apparatus according to the present invention. In FIG. 2, the configuration is shown in FIG.
The configuration is almost the same as that shown in (1), except that the microcomputer 3 further includes a power supply (battery voltage) detection input port P3, and the power supply 1 is connected to the port P3.

In the above configuration, the operation keys Sa to S
The reference voltage d is taken from the power supply (battery) 1 and the microcomputer 3 monitors the remaining amount of the battery and controls the operation key input according to the remaining voltage of the battery. That is, the microcomputer 3 determines the input voltage of the key input port P2 and the power detection input port P3.
It determines which operation key is turned on based on the ratio of the input voltage of the radio and controls each part of the radio.

FIG. 2 is a flowchart for judging on / off of the operation key by the microcomputer 3 described above. Here, for example, it is assumed that all the resistors R1 to R4 have the same resistance value, the input voltage of the battery detection input port P3 (that is, the battery voltage of the power supply 1) is Vref, and the key input port P
The input voltage of No. 2 will be described as A and the residual error voltage as α.
First, in step S1, the microcomputer 3 sets Vref-0.2
It is determined whether or not 5Vref ≧ A (or α + 0.75Vref ≧ A), and if no (ie, all operation keys are off), then the process returns to the start, and yes (ie, any operation key is turned on) ) Then S
Proceeding to 2, the microcomputer 3 determines whether or not α + 0.5 Vref ≧ A.

If the answer to S2 is no, it means that it is determined that the operation key Sa has been turned on.
The microcomputer 3 controls each part of the radio so as to perform a process corresponding to turning on the operation key Sa. If the answer to S2 is yes, it means that any one of the operation keys other than the operation key Sa has been turned on.
It is determined whether or not 0.25 Vref ≧ A. If the answer to S4 is NO, it means that it is determined that the operation key Sb has been turned on.
To control each part of the radio so as to perform a process corresponding to turning on the radio. If the answer to S4 is yes, it means that one of the operation keys other than the operation keys Sa and Sb has been turned on, and then the process proceeds to S6, where the microcomputer 3 determines whether or not α + 0 · Vref ≧ A.

If the answer to S6 is no, it means that it is determined that the operation key Sc has been turned on.
The microcomputer 3 controls each part of the radio so as to perform a process corresponding to turning on the operation key Sc. If the answer to S6 is yes, it means that it is determined that the operation key Sd has been turned on, and the process then proceeds to S8, where the microcomputer 3 controls each part of the radio to perform a process corresponding to the turning on of the operation key Sd.

According to the above embodiment, the operation power of the operation key circuit is supplied directly from the battery power supply, not from the DC / DC converter, and the microcomputer controls the input voltage of the key input port and the input voltage of the battery detection input port. (Reference voltage)
The radio key design determines which operation key is turned on, so even if the grounding locations of the operation keys are scattered due to the design of the radio set, the radiation caused by the noise of the DC / DC converter is reduced and the remaining voltage of the battery power supply is reduced. In the configuration shown in FIG. 1, when the battery voltage of the power supply 1 decreases, the key input port P of the microcomputer 3
Since the voltage applied to 1 fluctuates and the voltage range corresponding to the operation key includes the battery voltage fluctuation, a malfunction may occur. Therefore, the number of operation keys may be limited or the operation key may be set while the remaining battery voltage is high. And the number of operation keys is not restricted.

In the above embodiment, the voltage of the battery power source also varies depending on the load such as the volume and the drive of the motor.
Further, in the above embodiment, the DC / DC conversion circuit
Although a DC converter was used, the invention is not limited to this, and other circuits such as a stabilized power supply may be used. The signal input to the input port of the microcomputer is not limited to the signal from the operation key circuit, and may be connected to a battery power supply. An output signal of a control circuit such as an electric field strength detection circuit may be used. In this case, since the output signal of the control circuit fluctuates due to the fluctuation of the remaining voltage of the battery power supply, the same effect as in the above embodiment can be obtained.

[0019]

According to the present invention, since the power supply of the microcomputer and the power supply of the operation key circuit are separated, there is no restriction on the installation location of the operation keys, and interference from power supply noise and the like is reduced. Further, since the operation key is determined based on the ratio between the input voltage of the operation key input port and the power supply detection input voltage, the number of operation keys is not restricted.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of an electronic device according to the present invention.

FIG. 2 is a block diagram showing another embodiment of the electronic apparatus according to the present invention.

FIG. 3 is a flowchart for determining on / off of an operation key by a microcomputer in the block diagram of FIG. 2;

FIG. 4 is a block diagram illustrating an example of a conventional electronic device.

[Explanation of symbols]

 1 power supply 2 DC / DC converter 3 microcomputer 4 tuner 5 LCD 6 operation key circuit Sa operation key Sb operation key Sc operation key Sd operation key

Claims (3)

(57) [Claims] 1. An electronic apparatus comprising: a DC power supply; and a microcomputer which operates by being supplied with the DC power via a DC voltage conversion circuit, wherein each operation includes at least one operation key connected to the DC power supply. An operation key circuit for supplying a different voltage to the key input port of the microcomputer when operating the key is provided, and which operation key is operated is determined based on the input voltage supplied to the key input port. Electronics. 2. An electronic apparatus comprising: a DC power supply; and a microcomputer which operates by being supplied with the DC power through a DC voltage conversion circuit, wherein each operation includes at least one operation key connected to the DC power supply. An operation key circuit for supplying a different voltage to the key input port of the microcomputer at key-on, and a power supply detection input port for supplying the voltage of the DC power supply to the microcomputer as a reference voltage,
The electronic device according to claim 1, wherein the microcomputer determines which operation key is operated based on a ratio between an input voltage supplied to the key input port and a reference voltage supplied to the power detection input port. 3. An electronic apparatus comprising: a DC power supply; and a microcomputer which operates by being supplied with the DC power through a DC voltage conversion circuit, wherein the microcomputer is connected to the DC power supply, and an output thereof is provided to an input port of the microcomputer. And a power supply detection input port through which the voltage of the DC power supply is supplied as a reference voltage to the microcomputer, wherein the microcomputer has an input voltage supplied to the input port and the power supply detection input port. An electronic device for determining an output value of the control circuit based on a ratio of a reference voltage supplied to the electronic device.