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CN-116317520-B - Soft-on circuit for power supply switching and control method thereof

CN116317520BCN 116317520 BCN116317520 BCN 116317520BCN-116317520-B

Abstract

The invention provides a soft-on circuit for power supply switching, which comprises a first transistor for controlling first power supply input system equipment, a second transistor for controlling second power supply input system equipment and a plug detection circuit, wherein the plug detection circuit outputs a plug state signal to the control circuit. The control circuit comprises a first soft-on control circuit, a second soft-on control circuit and an inverter circuit, wherein the first soft-on control circuit is connected with the plug state signal through the inverter circuit and controls the first transistor to be turned off or turned on slowly, and the second soft-on control circuit is connected with the plug state signal and controls the second transistor to be turned off or turned on slowly. The soft-on control circuit with symmetrical circuit structure is designed, so that the power supply is stably and reliably switched smoothly, the power supply safety and reliability of system equipment are ensured, the circuit structure is simple and easy to integrate, and the production efficiency is improved and the application prospect is widened.

Inventors

  • ZHANG LIANG
  • JIANG LI
  • OU YUAN

Assignees

  • 珠海英集芯半导体有限公司

Dates

Publication Date
20260505
Application Date
20230327

Claims (10)

  1. 1. A soft-on circuit for power switching, comprising a first transistor (MP 0) controlling a first power supply (101) to be input to a system device (103), a second transistor (MP 1) controlling a second power supply (102) to be input to the system device (103), and a plug detection circuit (104), the plug detection circuit (104) being connected to the first power supply (101) and outputting a plug status signal (PINOUT) to a control circuit (100), the control circuit (100) being configured to control the operation states of the first transistor (MP 0) and the second transistor (MP 1) to switch the system device (103) to be input to the first power supply (101) or the second power supply (102), characterized in that the control circuit (100) comprises: The first soft-on control circuit (10), the second soft-on control circuit (20) and the inverting circuit (30), the first soft-on control circuit (10) is connected with the plug state signal (PINOUT) through the inverting circuit (30), the input end of the first soft-on control circuit (10) is connected with the first power supply (101) and the system equipment (103), the first soft-on control circuit (10) outputs a first switch control signal (PGATE 0) to the first transistor (MP 0), the second soft-on control circuit (20) is connected with the plug state signal (PINOUT), the input end of the second soft-on control circuit (20) is connected with the second power supply (102) and the system equipment (103), the second soft-on control circuit (20) outputs a second switch control signal (ATE 1) to the second transistor (MP 1), when the second switch control signal (PGATE 1) enables the second transistor (MP 1) to be connected with the first power supply (MP 0), and when the first switch control signal (PGATE 0) enables the first transistor (MP 0) to be slowly connected with the first power supply (MP 0) to be disconnected, and when the first ATE control signal (PGE 0) is slowly connected with the first power supply (MP 0), the second switch control signal (PGATE 1) causes the second transistor (MP 1) to slowly turn on until the input power value of the system device (103) slowly reaches the second power (102) value.
  2. 2. The soft-on circuit for power switching of claim 1, wherein: The source electrode of the first transistor (MP 0) is connected to the first power supply (101), the output capacitor (C0) is arranged on the connection path of the drain electrode of the first transistor and the system equipment (103), and the grid electrode of the first transistor is connected to the first switch control signal (PGATE 0).
  3. 3. The soft-on circuit for power switching of claim 1, wherein: The drain of the second transistor (MP 1) is connected to the second power supply (102), the source thereof is connected to the system device (103), and the gate thereof is connected to the second switch control signal (PGATE 1).
  4. 4. The soft-on circuit for power switching of claim 1, wherein: The first soft-on control circuit (10) and the second soft-on control circuit (20) have the same circuit structure and comprise an operational amplifier circuit (21), a differential voltage detection circuit (22), a sampling time sequence control circuit (23), a soft-on voltage circuit (24) and a first bias current circuit (25), an enabling end of the operational amplifier circuit (21) is connected with the plug state signal (PINOUT), the operational amplifier circuit (21) outputs a switch control signal (PGATE), the switch control signal (PGATE) is a first switch control signal (PGATE 0) or a second switch control signal (PGATE 1), the differential voltage detection circuit (22) is connected with an input power supply and a switching power supply of the system equipment (103), the switching power supply is a first power supply (101) or a second power supply (102), the differential voltage detection circuit (22) converts the differential voltage of the input power supply and the switching power supply of the system equipment (103) into a differential mode voltage signal (VDIFF) and outputs the differential mode voltage signal (VDF) to a second input end of the operational amplifier circuit (21), the differential voltage signal (23) is connected with the plug state signal (35) according to the differential time sequence, the plug state signal (PINOUT) is connected with the plug state signal (35), and sampling the maximum value of the differential mode voltage signal (VDIFF) according to the low-level sampling pulse Signal (SENCLK), wherein the soft-on voltage circuit (24) outputs a soft-on voltage (SS_VREF) to the first input end of the operational amplifier circuit (21), the first bias current circuit (25) is connected with a first bias current (IB), and the output end of the first bias current circuit is connected with the soft-on voltage circuit (24).
  5. 5. The soft-on circuit for power switching of claim 4, wherein: The differential voltage detection circuit (22) comprises a feedback operation circuit (221), a first current mirror circuit (222), a second current mirror circuit (223) and a second bias current circuit (224), wherein the feedback operation circuit (221) is connected with an input power supply of the system equipment (103) and the switching power supply, an output end of the feedback operation circuit (221) is connected with an input end of the first current mirror circuit (222), an output end of the first current mirror circuit (222) is connected with an input end of the second current mirror circuit (223), a common end of the first current mirror circuit is connected with a first potential, and an output end of the second current mirror circuit (223) outputs a differential mode voltage signal (VDIFF) and a common end of the second current mirror circuit is connected with a second potential.
  6. 6. The soft-on circuit for power switching of claim 5, wherein: The feedback operation circuit (221) comprises an operation amplifier (OP 2), a fourth transistor (MN 4) and a first resistor (R1), wherein an inverting input end of the operation amplifier (OP 2) is connected with an input power supply of the system equipment (103), a non-inverting input end of the operation amplifier (OP 2) is connected with the switching power supply through the first resistor (R1) and is in short circuit with a drain electrode of the fourth transistor (MN 4), an output end of the operation amplifier (OP 2) is connected with a grid electrode of the fourth transistor (MN 4), and a source electrode of the fourth transistor (MN 4) is connected with an input end of the first current mirror circuit (222).
  7. 7. The soft-on circuit for power switching of claim 4, wherein: The sampling time sequence control circuit (23) comprises a time delay module (231), a second inverter (INV 2) and a second NAND gate (ND 2), wherein the time delay module (231) is connected with the plug state signal (PINOUT), the output end of the time delay module (231) is connected with the first input end of the second NAND gate (ND 2) through the second inverter (INV 2), and the second input end of the second NAND gate (ND 2) is connected with the plug state signal (PINOUT).
  8. 8. The soft-on circuit for power switching of claim 5, wherein: The soft-on voltage circuit (24) comprises a second P-type transistor (MP 2), a third N-type transistor (MN 3) and a bypass capacitor (C1), wherein the gates of the second P-type transistor (MP 2) and the third N-type transistor (MN 3) are connected with the low-level sampling pulse Signal (SENCLK), the source of the second P-type transistor (MP 2) is connected with the differential mode voltage signal (VDIFF), the source of the third N-type transistor (MN 3) is connected with the output end of the first bias current circuit (25), the drains of the second P-type transistor (MP 2) and the third N-type transistor (MN 3) are connected with the first potential through the bypass capacitor (C1), and the drains of the second P-type transistor (MP 2) and the third N-type transistor (MN 3) output the soft-on voltage (SS_VREF).
  9. 9. The soft-on circuit for power switching of claim 8, wherein: The first bias current circuit (25) comprises a third current mirror circuit, the third current mirror circuit is connected to the first bias current (IB), the output end of the third current mirror circuit is connected with the source electrode of the third N-type transistor (MN 3), and the common end of the third current mirror circuit is connected with the first potential.
  10. 10. A control method of a soft-on circuit for power supply switching, characterized by being applied to a soft-on circuit for power supply switching as claimed in any one of claims 1 to 9, comprising: When the plug detection circuit (104) detects that the first power supply (101) is plugged in, the level of a plug state signal (PINOUT) is changed from high to low, at the moment, the output level of the second soft-on control circuit (20) is quickly pulled up, the second transistor (MP 1) is quickly turned off, the plug state signal (PINOUT) is input into the first soft-on control circuit (10) after being changed into high level through the inverter circuit (30), the output level of the first soft-on control circuit (10) slowly drops, so that the first transistor (MP 0) is slowly conducted until the input power supply value of the system equipment (103) slowly reaches the value of the first power supply (101), when the plug detection circuit (104) detects that the first power supply (101) is pulled out, the level of the plug state signal (PINOUT) is quickly changed from low to high, at the moment, the plug state signal (PINOUT) is input into the first soft-on control circuit (10) after being changed into low level through the inverter circuit (30), the output level of the first soft-on control circuit (10) quickly changes the input power supply value of the first transistor (MP 0) until the input power supply value of the second soft-on control circuit (103) rapidly changes the input power supply value of the second soft-on control circuit (103) slowly reaches the value of the second power supply (20), -enabling the system device (103) to switch between inputting the first power supply (101) and the second power supply (102).

Description

Soft-on circuit for power supply switching and control method thereof Technical Field The invention relates to the technical field of power supply switching, in particular to a soft-on circuit for power supply switching and a control method thereof. Background In multi-power supply product applications, power switching is an essential function, for example, in an emergency power server, when an abnormal power failure occurs in a main power supply circuit, the power supply is immediately switched to a standby power supply, so as to ensure that the power supply of the server is not interrupted. In addition, in a mobile power device, the system device is powered by the input power source when the adapter is plugged in and can be charged by the battery, and when the adapter is unplugged, the system device will be powered by the battery. As shown in fig. 1, fig. 1 is a power switching circuit, which includes a transistor MP200 for controlling an input power input system device 300, a transistor MP300 for controlling a standby power input system device 300, and a plug detection circuit 200, wherein the plug detection circuit 200 is used for detecting whether an input power source can normally supply power, and outputting a signal PINOUT to a buffer BUF0 and an inverter INV0, the buffer BUF0 outputting a signal PGATE3 to the transistor MP200, and the inverter INV0 outputting a signal PGATE4 to the transistor MP300. When an adapter is plugged into the input power supply, the plug detection circuit 200 detects that the input power supply is plugged into the input power supply, at this time, the signal PINOUT is changed from high to low, the signal PGATE4 is obtained after passing through the inverter INV0, the transistor MP300 is turned off, and at this time, the power supply of the standby power supply is rapidly disconnected. After the buffer BUF0 is passed, the signal PGATE3 is low, the transistor MP200 is turned on, and the input voltage VOUT1 of the system device 300 is rapidly increased from the standby power supply voltage BAT1 to the input power supply voltage VIN1. When the adapter of the input power source is pulled out, the plug detection circuit 200 detects that the input power source is pulled out, the signal PINOUT is changed from low to high, the signal PGATE3 is changed to high level, the transistor MP200 is turned off, and the standby input power source is rapidly turned off. The signal PGATE4 goes low, and the input voltage VOUT1 of the system device 300 drops rapidly from the input power voltage VIN1 to the standby power voltage BAT1. As shown in fig. 2, fig. 2 is a waveform diagram of the above power switching circuit, it can be seen that the larger the difference between the input power voltage VIN1 and the standby power voltage BAT1, the larger the transient change of the input voltage VOUT1 of the system apparatus 300, and the larger the influence of the power switching circuit on the system apparatus 300. Because the voltages of the power supplies are different, the power supply can be instantaneously changed when the power supplies are directly switched, and in some system equipment sensitive to the transient change of the power supplies, the system equipment can work abnormally due to the change, such as data loss or system shutdown, and the system equipment can be damaged, restarted, halted and even burnt out when serious. The prior art has the defects that: The use risk of the existing power supply switching circuit is high, the existing power supply switching circuit adopts direct switching, so that the transient change of the input power supply of the system equipment is increased along with the increase of the pressure difference of the switching power supply, and the risk of abnormal or even damaged operation of the system equipment is greatly increased; 2, the existing power supply switching circuit has poor applicability and cannot be suitable for system equipment sensitive to power supply transient variation; And 3, the reliability of the power supply is reduced by the existing power supply switching circuit. Therefore, a soft-on circuit for switching power supply is needed to smoothly switch power supply to improve the reliability of power supply and the applicability of the switched power supply circuit, and avoid the influence on the operation of system equipment caused by the excessive transient change of power supply. Disclosure of Invention The soft-on circuit for power supply switching and the control method thereof are mainly used for solving the problems that the transient change of the existing power supply switching circuit affects the operation of system equipment, reduces the applicability of the switching circuit, the reliability of the power supply and the like when the power supply is switched, thereby achieving the effects of smoothly switching the power supply to avoid the transient change when the power supply is switched and improving the applicability and the r