JPS63245219A - Electric source - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a power supply device, and particularly to a power supply device that supplies operating power to electronic circuit devices such as a microprocessor or a memory device, as well as a device that operates these electronic circuit devices. The present invention relates to a power supply device that can also generate a control signal such as an initial signal for enabling or disabling the operation.

[Prior Art] Recently, in electronic four-way devices such as microprocessors or semiconductor memories, when power is turned on and off to these electronic circuits, these electronic circuit devices are initialized to be in an operational state, or A control signal called an initial signal is used to save the state of each register in a memory and cancel its operation.

Conventionally, a power supply device shown in FIG. 2, for example, has been used as a power supply device for supplying an operating power source and a control signal to such an electronic circuit device.

The power supply device shown in the figure is a D.
It is composed of a C power supply section 2, a control section 4 that determines the generation timing of the initial signal, a driver transistor 6 of, for example, an NPN type, a base resistor 8 and a collector resistor 10 of the transistor 6, and the like. Note that 12 is a microprocessor operated by this power supply device, and this microprocessor may be, for example, a semiconductor memory, or a combination of a microprocessor and a semiconductor memory.

In the power supply device of FIG. 2, for example, as shown in FIG. 3, when an AC input voltage g (a) is applied, a DC voltage of, for example, +5 volts is first generated at the output (b) of the DC power supply section 2. do. Then, when this DC voltage rises sufficiently, the output of the control section 4 is switched from a high level to a low level. As a result, the driver transistor 6 is cut off, and the initial signal output to the collector (C) of the transistor 6 changes to a high level. This allows the CPU
The microprocessor 12 such as the microprocessor 12 becomes operational and performs a predetermined data processing operation. In addition, the AC input power supply (
a) is cut off, the control section 4 first turns on the driver transistor 6 and outputs the initial signal (C
) changes from a high level to a low level. At this time, the output (b) of the DC power supply unit 2 continues to supply power for a while even after the AC input power is cut off, by using, for example, a large capacity capacitor. During this time, the microprocessor 12 saves the contents of each register, flag, etc. to memory. Thereby, information necessary for the next operation of the microprocessor 12 is retained even after the DC power supply is completely cut off.

[Problems to be Solved by the Invention] However, in the conventional power supply device described above, for example, during the period when the AC input power is applied and the DC power is turned on, and during the period when the DC power is turned off after the AC power is cut off, Since the driver transistor 6 cannot be kept completely on, spike noise is generated in the initial signal, which causes the microprocessor to malfunction.

That is, since the control unit 4 itself is also supplied with power from the DC power supply unit 2, for example, when the DC power supply starts up, the control unit 4
The output voltage of the driver transistor 6 may not be high enough, and therefore the driver transistor 6 may not be able to be kept completely in the on state. Therefore, the collector potential of the driver transistor 6 is temporarily raised by the collector resistor 10, causing spike-like noise in the initial signal as shown by the dotted line in FIG. 3(C). This also applies when the DC power supply falls.

SUMMARY OF THE INVENTION Therefore, in view of the above-mentioned problems with the conventional type, an object of the present invention is to provide a power supply device that supplies power to a microprocessor, etc., with a simple circuit configuration that eliminates noise in control signals such as initial signals even when the power is turned on and off. To prevent this from occurring, and to properly prevent malfunctions of electronic circuit devices.

[Means for Solving the Problems] In the power supply device according to the present invention, in addition to the power supply for operating the electronic circuit device, an initial signal for setting the electronic circuit device to an operable state or an operation disable state is provided. An initial signal blocking circuit is provided that prevents generation of the initial signal until the operating power supply reaches, for example, a predetermined value or more. Examples of the electronic circuit device include a microprocessor or a semiconductor memory.

[Function] In the above-mentioned power supply device, the initial signal is not supplied to the electronic circuit device until the operating power supply voltage rises to a predetermined value or higher due to the function of the initial signal blocking circuit, and the operating power supply voltage is Supply of the initial signal is also blocked when the voltage falls below a predetermined value. Therefore, generation of noise in the initial signal due to unstable operation of the driver transistor of the initial signal supply circuit at the time of rising or falling of the operating power supply voltage is completely prevented.

[Example code] Hereinafter, the present invention will be explained in detail with reference to the drawings.

FIG. 1 shows the configuration of a power supply device according to an embodiment of the present invention. The power supply device of the same figure has a PN transistor instead of the collector resistor 10 of the driver transistor 6 in the power supply device of FIG.
P A series circuit of a transistor 14 and a resistor 16, and a resistor 1 for supplying the base pressure of this transistor 14.
8.20 and a Zener diode 22 are connected. The other parts are the same as those in FIG. 2, and the same parts are designated by the same reference numerals.

Also in the power supply device of FIG. 1, as shown in FIG.
When the C input power supply (a) is turned on, the DC power supply (b) which is the output of the DC power supply unit 2 is turned on, and the operating power for the microprocessor 12 and the like is supplied.

After the DC power supply is completely turned on, the output of the control section 4 changes from high level to low level, driver transistor 6 is turned off, and the initial signal (C) changes from low level to high level. As a result, the microprocessor 12 and the like enter an operable state or a set state and perform predetermined processing operations. Furthermore, when the AC input power is cut off, a high level voltage is supplied to the base of the driver transistor 6 by the action of the control unit 4, the transistor 6 is turned on, and the initial signal (C) changes from high level to low level. do.

In response to this change, the microprocessor 12 and the like perform operations such as saving predetermined data into memory. Thereafter, the DC power supply (b) also changes to a low level, and the microprocessor 12 and the like stop operating.

In the above operation, when the AC input power supply (a) is turned on and the DCTIXi source (b) is turned on, if the voltage of the DC power supply (b) is below a predetermined value, the emitter voltage of the PNP transistor 14 will be the same as that of the Zener diode 22 and The base voltage is lower than the base voltage determined by the DC power supply voltage, etc., so the transistor 14 is cut off. Therefore, even if the output voltage of the control section 4 is not high enough to completely turn on the driver transistor 6, the voltage at the collector (C) of the transistor 6 is prevented from rising inadvertently. That is, for example, in a case where the operating power of the control unit 4 is supplied from the DC power supply unit 2, the output voltage of the control unit 4 is not high enough when the power is turned on, and therefore the driver transistor 6 is turned on. Even if this is impossible, the potential at the collector (C) of the transistor 6 does not rise because the transistor 14 connected to the collector of the driver transistor 6 is cut off.

The above operation is also applied when the DC power supply falls, so that even when the AC input power supply is cut off, no noise is generated in the initial signal (C).

[Effects of the Invention] As described above, according to the present invention, fluctuations in the initial signal during transient operation of the driver transistor, that is, noise, can be removed with an extremely simple circuit configuration. Therefore, it is possible to accurately prevent malfunctions of the microprocessor and other electronic circuit devices during power-on and power-off.

[Brief explanation of the drawing]

FIG. 1 is a block circuit diagram showing the configuration of a power supply device according to an embodiment of the present invention, FIG. 2 is a block circuit diagram showing the configuration of a conventional power supply device, and FIG. 3 is a block diagram showing the configuration of a conventional power supply device. 3 is a waveform diagram for explaining the operation of the power supply device of FIG. 2. FIG. 2: DC power supply section, 4: Control section, 6: Driver transistor, 8. 10, 16, 18, 20: Resistor, 12: Microprocessor, 14: PNP) transistor, 22: Zener diode.

Claims (1)

[Scope of Claims] 1. An operating power supply unit that generates an operating power supply to be supplied to an electronic circuit device, and an initial signal supply that generates an initial signal for setting the electronic circuit device to an operable state or an operation-disabled state. and an initial signal blocking circuit that prevents the generation of the initial signal until the operating power supply reaches a predetermined value or more or a predetermined value or less. 2. The power supply device according to claim 1, wherein the electronic circuit device is a microprocessor and/or a memory device.