CN104238703A - Power circuit - Google Patents

Abstract

The invention discloses a power circuit which comprises a first electronic switch, a second electronic switch, a third electronic switch and a switch chip. The power circuit alternately switches voltages of a first voltage standby power source and a first voltage source both connected with the switch chip into a voltage of a voltage output end through connection among the first to third electronic switches. Therefore, the voltage output end can output a steady and reliable auxiliary voltage no matter before and after start-up, and demands of more loads are accordingly satisfied.

Description

power circuit

technical field

The invention relates to a power circuit.

Background technique

The power supply is the power part of electronic equipment (such as desktop computer, notebook computer, server, etc.), and the electric energy of each component in the electronic equipment comes from the power supply. Usually, the motherboard includes a voltage output terminal P5V_AUX, which is used to enable the system to implement a suspend mode, and provide a small current when some components stop working, so that these components can quickly resume their working status. However, the P5V_AUX on the motherboard usually supplies power to multiple loads. How to make the voltage output terminal P5V_AUX output a stable and reliable voltage to the connected loads before or after power-on, so as to enhance the load-carrying capacity of the voltage output terminal P5V_AUX Ability is a problem that needs to be solved urgently.

Contents of the invention

In view of the above, it is necessary to provide a power supply circuit capable of outputting a reliable and stable auxiliary voltage to meet the demands of more loads.

A power circuit, comprising first to third electronic switches and a switch chip, the first end of the first electronic switch receives a power ready signal, the second end of the first electronic switch is grounded, the first The third end of an electronic switch is connected to a first voltage backup power supply through a first resistor, the first end of the second electronic switch is connected to the second end of the first electronic switch, and the second electronic switch The second terminal of the second electronic switch is grounded, the third terminal of the second electronic switch is connected to a working power supply through a second resistor, the first terminal of the third electronic switch is connected to the first terminal of the second electronic switch, and the first terminal of the second electronic switch is connected to the first terminal of the second electronic switch. The second terminal of the three electronic switches is grounded, the third terminal of the third electronic switch is connected to the working power supply through a third resistor, the first pin of the switch chip is connected to a first voltage source, and the switch The second pin of the chip is connected to the third terminal of the second electronic switch, the third pin of the switch chip is connected to the first voltage backup power supply, and the fourth pin of the switch chip connected to the third terminal of the third electronic switch, the fifth to eighth pins of the switch chip are connected to a voltage output terminal, when the power supply control terminal sends a high level signal, the first The electronic switch is turned on, the second and third electronic switches are turned off, the first pin of the switch chip receives the voltage of the first voltage source, and outputs the voltage to the seventh and eighth pins of the switch chip voltage output terminal; when the power control terminal sends a low level signal, the first electronic switch is turned off, the second and third electronic switches are turned on, and the third pin of the switch chip receives the The voltage of the first voltage backup power supply is output to the voltage output terminals connected to the fifth and sixth pins of the switch chip.

The power supply circuit of the present invention can alternately supply power to the voltage output terminal through a first voltage backup power supply and the first voltage source, so that the voltage output terminal can output a stable and reliable auxiliary voltage no matter before or after starting up, so as to meet more loads demand.

Description of drawings

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

Fig. 2 is a schematic diagram of a switch chip of the power supply circuit of the present invention.

Description of main component symbols

power circuit 10 first electronic switch Q1 second electronic switch Q2 third electronic switch Q3 switch chip U1 resistance R0-R3 capacitance C1-C3 Fourth electronic switch Q4 Fifth electronic switch Q5

The following specific embodiments will further illustrate the present invention in conjunction with the above-mentioned drawings.

Detailed ways

Please refer to FIG. 1 , a preferred embodiment of the power circuit 10 of the present invention includes first to third electronic switches Q1 - Q3 and a switch chip U1 . The power supply circuit 10 receives a power ready signal PWRGD_PS, the switch chip U1 is connected between a first voltage source P5V, a first voltage backup power supply P5V_STBY and a voltage output terminal P5V_AUX, and according to the power ready signal POWGD_PS The state selection of the first voltage standby power supply P5V_STBY or the voltage of the first voltage source P5V is respectively switched to the voltage output terminal P5V_AUX. The voltage output terminal P5V_AUX is used to provide the auxiliary voltage 5V to corresponding electronic components.

The first end of the first electronic switch Q1 receives a power ready signal PWRGD_PS through a resistor R0, the second end of the first electronic switch Q1 is grounded, and the third end of the first electronic switch Q1 is connected through a resistor R0 R1 is connected to the first voltage standby power supply P5V_STBY. The first terminal of the second electronic switch Q2 is connected to the third terminal of the first electronic switch Q1, the second terminal of the second electronic switch Q2 is grounded, and the third terminal of the second electronic switch Q2 passes through a resistor R2 is connected to a working power supply P12V. The first terminal of the third electronic switch Q3 is connected to the first terminal of the second electronic switch Q2, the second terminal of the third electronic switch Q3 is grounded, and the third terminal of the third electronic switch Q3 passes through a resistor R3 is connected to the working power supply P12V. The first pin S1 of the switch chip U1 is connected to the first voltage source P5V, the second pin G1 of the switch chip U1 is connected to the third terminal of the second electronic switch Q2, and the switch chip The third pin S2 of U1 is connected to the first voltage backup power supply P5V_STBY, the fourth pin G2 of the switch chip U1 is connected to the third terminal of the third electronic switch Q3, and the first pin G2 of the switch chip U1 The fifth to eighth pins D2_2 , D2_1 , D1_2 and D1_1 are all connected to the voltage output terminal P5V_AUX. The first pin S1 of the switch chip U1 is grounded through a capacitor C1, the third pin S3 of the switch chip U1 is grounded through a capacitor C2, and the fifth to eighth pins D2_2, D2_1 of the switch chip U1 , D1_2 and D1_1 are all grounded through a capacitor C3.

2, the switch chip U1 includes a fourth electronic switch Q4 and a fifth electronic switch Q5, the first end of the fourth electronic switch Q4 is connected to the second pin G1 of the switch chip U1, the first The second end of the four electronic switch Q4 is connected to the first pin S1 of the switch chip U1 , and the third end of the fourth electronic switch Q4 is connected to the seventh and eighth pins D1_2 and D1_1 of the switch chip U1 . The first end of the fifth electronic switch Q5 is connected to the fourth pin G2 of the switch chip U1, the second end of the fifth electronic switch Q5 is connected to the third pin S2 of the switch chip U1, and the fifth The third end of the electronic switch Q5 is connected to the fifth and sixth pins D2_2 and D2_1 of the switch chip U1.

In this embodiment, the first to fourth electronic switches Q1-Q4 are all NMOS field effect transistors, the fifth electronic switch is a PMOS field effect transistor, and the first terminals of the first to fifth electronic switches , the second terminal and the third terminal respectively correspond to the gate, the source and the drain of the field effect transistor.

After starting up, when the power ready signal PWRGD_PS is at a high level, the first electronic switch Q1 is turned on, the second and third electronic switches Q2 and Q3 are turned off, and the fourth electronic switch of the switch chip U1 Q4 is turned on, and the fifth electronic switch Q5 is turned off. The first pin S1 of the switch chip U1 receives the voltage of the first voltage source P5V, and outputs it to the seventh pin D1_2 and the eighth pin of the switch chip U1. The voltage output terminal P5V_AUX connected to the pin D1_1 makes the voltage output terminal P5V_AUX output an auxiliary voltage of 5V.

During standby, when the power ready signal PWRGD_PS is at low level, the first electronic switch Q1 is turned off, the second and third electronic switches Q2 and Q3 are turned on, and the fourth electronic switch Q4 of the switch chip U1 is turned off, and the fifth electronic switch Q5 is turned on, the third pin S2 of the switch chip U1 receives the voltage of the first voltage backup power supply P5V_STBY, and outputs it to the fifth pin D2_2 and the sixth pin D2_2 of the switch chip U1. The voltage output terminal P5V_AUX connected to the pin D2_1 makes the voltage output terminal P5V_AUX output the auxiliary voltage 5V.

In summary, when the power ready signal PWRGD_PS is at low level, the first voltage backup power supply P5V_STBY supplies voltage to the voltage output terminal P5V_AUX; when the power ready signal PWRGD_PS is at high level, the first voltage source P5V supplies voltage to the voltage output terminal P5V_AUX provides voltage. In this way, the voltage output terminal P5V_AUX has a stable auxiliary voltage 5V output no matter when the host is in standby or after it is turned on, so as to meet the needs of more loads.

Claims (4)

1. A power supply circuit, comprising first to third electronic switches and a switch chip, the first end of the first electronic switch receives a power ready signal, the second end of the first electronic switch is grounded, and the The third terminal of the first electronic switch is connected to a first voltage backup power supply through a first resistor, the first terminal of the second electronic switch is connected to the third terminal of the first electronic switch, and the The second end is grounded, the third end of the second electronic switch is connected to a working power supply through a second resistor, the first end of the third electronic switch is connected to the first end of the second electronic switch, and the third The second end of the electronic switch is grounded, the third end of the third electronic switch is connected to the working power supply through a third resistor, the first pin of the switch chip is connected to a first voltage source, and the switch chip The second pin of the switch chip is connected to the third terminal of the second electronic switch, the third pin of the switch chip is connected to the first voltage backup power supply, the fourth pin of the switch chip is connected to the first The third terminals of the three electronic switches are connected, the fifth to eighth pins of the switch chip are connected to a voltage output terminal, and when the power ready signal received by the first terminal of the first electronic switch is a high level signal, the first electronic switch is turned on, the second and third electronic switches are turned off, and the first pin of the switch chip receives the voltage of the first voltage source and outputs it to the seventh pin of the switch chip. and the voltage output end connected to the eighth pin; when the power ready signal received by the first end of the first electronic switch is a low-level signal, the first electronic switch is turned off, and the second and second The three electronic switches are turned on, and the third pin of the switch chip receives the voltage of the first voltage backup power supply and outputs it to the voltage output terminals connected to the fifth and sixth pins of the switch chip. 2. The power circuit according to claim 1, wherein the switch chip comprises a fourth electronic switch and a fifth electronic switch, the first end of the fourth electronic switch is connected to the second lead of the switch chip The pins are connected, the second end of the fourth electronic switch is connected with the first pin of the switch chip, the third end of the fourth electronic switch is connected with the seventh and eighth pins of the switch chip, and the fifth The first terminal of the electronic switch is connected to the fourth pin of the switch chip, the second terminal of the fifth electronic switch is connected to the third pin of the switch chip, and the third terminal of the fifth electronic switch is connected to the pin of the switch chip. The fifth and sixth pins are connected. 3. The power supply circuit according to claim 2, wherein the first pin of the switch chip is grounded through a first capacitor, the third pin of the switch chip is grounded through a second capacitor, and the The fifth to eighth pins of the switch chip are grounded through a third capacitor. 4. The power supply circuit according to claim 2, wherein the first to fourth electronic switches are NMOS field effect transistors, the fifth electronic switch is a PMOS field effect transistor, and the first to fifth The first terminal, the second terminal and the third terminal of the electronic switch respectively correspond to the gate, the source and the drain of the field effect transistor.