TWI438613B - Computer power supply and standby voltage discharge circuit - Google Patents

Description

Computer power supply and standby voltage discharge circuit thereon

The present invention relates to a computer power supply, and more particularly to a discharge circuit that discharges a standby voltage thereto.

In the design verification of the computer motherboard, there is a project that must be tested, that is, AC power on/off test. Specifically, the external AC power supply for the computer power supply is automatically powered and powered off at a certain time, and the computer motherboard is also required to automatically power on and off, so as to simulate the operation of the unmanned switch. In the test, if the external AC power supply has a short power-off time and immediately resumes power supply, the computer motherboard may not automatically boot. The reason for the above situation is that after the external AC power supply is powered off, the 5V standby voltage on the computer power supply is discharged for too long, and the 5V standby voltage is not completely discharged to low when the external AC power supply is powered off and immediately resumes power supply. The level causes the computer motherboard to think that it is abnormally shut down, so that the computer motherboard cannot be turned on again when the external AC power is restored.

In view of the above, it is necessary to provide a computer power supply that rapidly discharges a standby voltage and a standby voltage discharge circuit thereon.

A computer power supply includes a standby voltage output terminal for outputting a standby voltage and a power connector connected to a standby voltage output pin on the power connector, the computer power source further including a standby voltage discharge a standby voltage discharge circuit comprising a voltage stabilizing diode, a capacitor, first and second electrical switches, wherein the standby voltage output pin is connected to a cathode of the voltage stabilizing diode, the voltage stabilizing diode An anode is connected to the first end of the first electrical switch, a second end of the first electrical switch is grounded, and a third end of the first electrical switch is connected to the first end of the second electrical switch and is connected to the second electrical switch The standby voltage output end is connected to the second end of the second electric switch, and the third end of the second electric switch is connected to the standby voltage output terminal through a resistor, the capacitor is connected between the standby voltage output end and the ground The first and second electrical switches are turned on when the first terminal is at a high level, and are turned off when the first terminal is at a low level.

A standby voltage discharge circuit for discharging a standby voltage in a computer power supply, the standby voltage discharge circuit comprising a voltage regulator diode, a capacitor, first and second electrical switches, and the voltage regulator diode Receiving the standby voltage, the anode of the voltage stabilizing diode is connected to the first end of the first electrical switch, the second end of the first electrical switch is grounded, and the third end of the first electrical switch is connected to the first The first end of the second electric switch receives the standby voltage through a resistor, the second end of the second electric switch is grounded, and the third end of the second electric switch receives the standby voltage through a resistor, and the capacitor is connected to the standby Between the voltage and the ground, the first and second electrical switches are turned on when the first terminal is at a high level, and are turned off when the first terminal is at a low level.

When the external AC power supply connected to the computer power supply is powered off, the second switch of the standby voltage discharge circuit is in an on state, so that the capacitor receiving the standby voltage can be quickly discharged through the second switch, thereby ensuring connection. The computer motherboard of the computer power supply can automatically start up automatically when the external AC power supply is quickly restored.

Referring to FIG. 1, the computer power supply 10 of the present invention is used to supply power to a computer motherboard (not shown). The preferred embodiment includes a standby voltage output terminal 5V_STBY, a standby voltage discharge circuit 12, and a computer for connecting to the computer. The power connector 14 of the motherboard. The standby voltage output terminal 5V_STBY is used to output a 5V standby voltage to the standby voltage output pin +5V_AVX of the power connector 14 and the standby voltage discharge circuit 12 for quickly discharging the 5V standby voltage. . The circuit for generating the standby voltage is a conventional technology. The connection between the other pins of the power connector 14 and the internal circuit of the computer power supply 10 is also a conventional technique, and is not shown in the drawings. .

The standby voltage discharge circuit 12 includes three resistors R1-R3, a voltage stabilizing diode D, a capacitor C, and two transistors Q1 and Q2 as electrical switches.

One end of the resistor R1 is connected to the standby voltage output terminal 5V_STBY and the standby voltage output pin +5V_AVX of the power connector 14, and the other end of one end of the resistor R1 is connected to the cathode of the voltage stabilizing diode D. The anode of the piezoelectric diode D is connected to the base (first end) of the transistor Q1, the emitter (second end) of the transistor Q1 is grounded, and the collector (third end) of the transistor Q1 is connected to One end of the resistor R2 and the base (first end) of the transistor Q2, the other end of the resistor R2 is connected to the standby voltage output terminal 5V_STBY, and the emitter (second end) of the transistor Q2 is grounded. The collector (third terminal) of the crystal Q2 is connected to the standby voltage output terminal 5V_STBY through the resistor R3, and the capacitor C is connected between the standby voltage output terminal 5V_STBY and the ground.

In the present embodiment, the voltage regulator diode D has a voltage regulation voltage of 3.6 V, and can be adjusted according to the discharge time and the requirements of the power source. In other embodiments, the two transistors Q1 and Q2 can be selected from other types of electrical switches, such as relays, field effect transistors, etc., and the resistor R1 as a current limiting resistor can be omitted to further reduce the cost.

During operation, when the standby voltage output terminal 5V_STBY is in the power-on state, that is, when the 5V standby voltage is output, the Zener diode D is in an on state, so that the transistor Q1 is also turned on, and the transistor Q2 is turned off. Therefore, the standby voltage discharge circuit 12 does not have any influence on the computer power supply 10 at this time, that is, it does not affect its operation.

When the external AC power source (not shown) connected to the computer power source 10 is powered off, the standby voltage output terminal 5V_STBY starts to be powered down, and when it falls to a preset value (such as 4.3V), the voltage regulator diode D is turned off, so that the transistor Q1 is also turned off, and the transistor Q2 is turned on, so that the capacitor C receiving the standby voltage output terminal 5V_STBY voltage realizes rapid discharge through the resistor R3 and the transistor Q2, thereby achieving the The standby voltage output terminal 5V_STBY is used for rapid discharge.

When the computer power supply 10 of the present invention is used for the AC switch test, the standby voltage discharge circuit 12 can make the 5V standby voltage outputted by the standby voltage output terminal 5V_STBY fast when the external AC power supply is powered off for a short time and immediately resumes power supply. Discharge, thus ensuring that the computer motherboard can automatically start up normally.

In summary, the present invention complies with the requirements of the invention patent and submits a patent application according to law. The above description is only the preferred embodiment of the present invention, and equivalent modifications or variations made by those skilled in the art will be included in the following claims.

10‧‧‧Computer power supply
12‧‧‧Separate voltage discharge circuit
14‧‧‧Power connector
R1-R3‧‧‧ resistance
Q1-Q2‧‧‧O crystal
D‧‧‧Regulators
C‧‧‧ capacitor

1 is a circuit diagram of a preferred embodiment of a computer power supply of the present invention.

10‧‧‧Computer power supply

12‧‧‧Separate voltage discharge circuit

14‧‧‧Power connector

R1-R3‧‧‧ resistance

Q1-Q2‧‧‧O crystal

D‧‧‧Regulators

C‧‧‧ capacitor

Claims (10)

A computer power supply includes a standby voltage output terminal for outputting a standby voltage and a power connector connected to a standby voltage output pin of the power connector, wherein the computer power supply further includes a standby voltage discharge circuit, the standby voltage discharge circuit includes a voltage stabilizing diode, a capacitor, first and second electrical switches, and the standby voltage output pin is connected to the cathode of the voltage stabilizing diode, the voltage regulator The anode of the diode is connected to the first end of the first electrical switch, the second end of the first electrical switch is grounded, and the third end of the first electrical switch is connected to the first end of the second electrical switch and a resistor is connected to the standby voltage output terminal, a second end of the second electrical switch is grounded, and a third end of the second electrical switch is connected to the standby voltage output terminal through a resistor, and the capacitor is connected to the standby voltage output terminal Between ground and ground, the first and second electrical switches are turned on when the first terminal is at a high level, and turned off when the first terminal is at a low level. The computer power supply of claim 1, wherein a resistor is connected in series between the voltage stabilizing diode and the standby voltage output pin. The computer power supply of claim 1, wherein the first and second electronic switches are all transistors, and the first to third ends of the first and second electronic switches respectively correspond to a base of the transistor, Emitter, collector. The computer power supply of claim 1, wherein the voltage regulator diode has a voltage regulation voltage of 3.6V. The computer power supply of claim 1, wherein the standby voltage is 5V. A standby voltage discharge circuit for discharging a standby voltage in a computer power supply, the standby voltage discharge circuit comprising a voltage regulator diode, a capacitor, first and second electrical switches, and the voltage regulator diode Receiving the standby voltage, the anode of the voltage stabilizing diode is connected to the first end of the first electrical switch, the second end of the first electrical switch is grounded, and the third end of the first electrical switch is connected to the first The first end of the second electric switch receives the standby voltage through a resistor, the second end of the second electric switch is grounded, and the third end of the second electric switch receives the standby voltage through a resistor, and the capacitor is connected to the standby Between the voltage and the ground, the first and second electrical switches are turned on when the first terminal is at a high level, and are turned off when the first terminal is at a low level. The standby voltage discharge circuit of claim 6, wherein the voltage stabilizing diode receives the standby voltage through a resistor. The standby voltage discharge circuit of claim 6, wherein the first and second electronic switches are all transistors, and the first to third ends of the first and second electronic switches respectively correspond to a base of the transistor. Pole, emitter, collector. The standby voltage discharge circuit of claim 6, wherein the voltage regulator diode has a voltage regulation voltage of 3.6V. The standby voltage discharge circuit of claim 6, wherein the standby voltage is 5V.