TWI687015B - Power supply with surge current suppression - Google Patents

Abstract

The invention provides a power supply with surge current suppression. The power supply enters a startup mode or a shutdown mode based on the potential of an on-off signal. The power supply includes a power factor correction unit and a startup control unit connected to the power factor correction unit. The power factor correction unit has a voltage stabilizing capacitor, a thermistor connected in series with the voltage stabilizing capacitor, and a parallel thermistor The first switch of the resistor, the startup control unit has a startup mode that activates the power factor correction unit during the startup mode and turns on the first switch to short-circuit the thermistor, and turns off the power during the shutdown mode Because the correction unit also turns off the first switch, the thermistor can suppress the shutdown mode of the inrush current flowing into the power correction unit.

Description

Power supply with surge current suppression

The invention relates to a power supply, especially a power supply with surge current suppression.

When the power supply is ready to start after receiving an AC power source (such as a commercial power supply), all components (including the voltage-stabilizing capacitor) connected in series with a voltage-stabilizing capacitor in a power factor correction unit of the power supply will withstand a very large surge Inrush current (also known as surge current or inrush current). Now, in order to avoid the impact of the aforementioned surge current on the power supply circuit and damage the power supply, related companies have proposed suppression solutions, such as TW I290405, TW I474592, TW I494747, TW M268615, TW 200934029 Uncovered.

Among them, in the patent case of TW I290405, which discloses a surge current control circuit, the patent case provides a first control unit and a second control unit in an impedance series connection mode in the main circuit. The control unit and the second control unit both have a current limiting resistor and a controlled switch connected in parallel with each other. The current limiting resistor of the first control unit is used to prevent a surge current generated when the AC power is turned on, and its controlled switch is turned on according to the voltage of the energy storage capacitor, so that the current crosses the first current limit Resistance, and the current-limiting resistance of the second control unit is used to prevent the surge current generated at the moment of the level switching of the AC power supply, and its controlled switch is turned on according to the AC power supply to make the current cross the second current limiting resistance. In this connection, although the TW I290405 patent case proposes a technical solution for suppressing surge current, both the first control unit and the second control unit are implemented with additional control circuits. Such implementation will make the overall circuit layout and system control trend It is complicated and increases the cost of the circuit.

Furthermore, the TW 200934029 patent case discloses an inrush current suppression circuit, which is connected between a rectifier circuit and a filter circuit, and includes a current limiting resistor, a capacitor, and a three-terminal active element, the The active components are connected in parallel with the capacitor and the current limiting resistor, respectively. When the power is turned on, the current first flows through the current-limiting resistor and charges the capacitor. When the capacitor is charged to a voltage value that can actuate the active element, the active element turns on immediately and short-circuits the current-limiting resistor in parallel with it. Furthermore, the power consumption caused by the current limiting resistor during power supply is reduced. As a result, although the TW 200934029 patent case also proposed a technical solution to suppress the surge current, the many components used in TW 200934029 will lead to the circuit design must be reconsidered, and the driving of the aforementioned active components involves the voltage of each point connected to it, so that The driving circuit of the aforementioned active element is not easy to realize.

The main purpose of the present invention is to solve the problem that the conventional implementation will lead to complicated circuit composition or difficult control.

To achieve the above object, the present invention provides a power supply with surge current suppression. The power supply enters a startup mode or a shutdown mode based on the potential of an on-off signal sent by a load. The power supply includes a power factor correction unit and a start-up control unit connected to the power factor correction unit. The power factor correction unit has a voltage stabilizing capacitor, a thermistor connected in series with the voltage stabilizing capacitor, and a parallel the heat The first switch of the varistor. The startup control unit has a startup mode that activates the power factor correction unit and turns on the first switch to short-circuit the thermistor when the power supply enters the startup mode, and one enters the shutdown mode when the power supply enters When the power factor correction unit is turned off and the first switch is turned off in conjunction, the thermistor can suppress the shutdown mode of the inrush current flowing into the power factor correction unit.

In an embodiment, the first switch has a power input terminal connected to the voltage stabilizing capacitor, a control terminal connected to the startup control unit, and a first ground terminal, and the thermistor has a first terminal connected to the power input terminal One end, and a second end connected to the first grounding end.

In one embodiment, the startup control unit has a second ground terminal connected to the first ground terminal so that the startup control unit and the power factor correction unit form a common ground and an operating voltage input terminal connected to the control terminal, When the startup control unit is in the startup mode, a voltage difference is formed between the operating voltage input terminal and the second ground terminal, and the voltage difference causes the first switch to be turned on.

In one embodiment, the power supply includes a rectification input unit disposed at the front stage of the power factor correction unit.

In one embodiment, the power supply includes a power conversion unit disposed behind the power factor correction unit.

In an embodiment, the first switch may be a double carrier junction transistor, a field effect transistor, or a metal oxide half field effect transistor.

Through the foregoing disclosure of the present invention, it has the following advantages over conventional ones: The present invention enables the activation control unit to activate the power factor correction unit while simultaneously turning on the first switch. On the other hand, the start control unit shuts off the power factor correction unit and simultaneously shuts off the first switch, so that the control circuit for controlling the first switch can be omitted, which not only simplifies the complexity of system control, The reliability of the system control is further improved, and there is no need to increase the cost of implementing additional driving circuits.

100: power supply

10: Power factor correction unit

11: Start the control unit

111: second ground

112: working voltage input

12: Voltage stabilizing capacitor

13: Thermistor

131: the first end

132: Second end

14: The first switch

141: Power input

142: Control terminal

143: First ground terminal

15: Rectifier input unit

16: Power conversion unit

200: load

300: AC power source

40, 41: current path

42: opening and closing signal

FIG. 1 is a schematic diagram of unit composition according to an embodiment of the invention.

FIG. 2 is a circuit schematic diagram of an embodiment of the invention.

FIG. 3 is a schematic diagram of an implementation of a startup mode according to an embodiment of the invention.

FIG. 4 is a schematic diagram of an implementation of a shutdown mode according to an embodiment of the invention.

The detailed description and technical content of the present invention will now be explained in conjunction with the drawings as follows: Please refer to FIG. 1, the present invention provides a power supply 100 with surge current suppression. The power supply 100 is mainly configured in a personal computer (PC) Or an industrial computer (IPC), the power supply 100 is implemented based on ATX motherboard specifications. According to this, the power supply 100 is connected to a load 200. When the load 200 is operated and is about to start, the load 200 sends an on/off signal 42 to the power supply 100 to a low potential. The power supply 100 according to the The start-stop signal 42 enters a start-up mode, ready to output the power required for the work to the load 200. On the other hand, when the load 200 is operated and will stop working, the on-off signal 42 sent by the load 200 to the power supply 100 is at a high potential (or open circuit), and the power supply 100 is based on the current The opening and closing signal 42 enters a shutdown mode and stops outputting the power required for the work to the load 200. Furthermore, the start-stop signal 42 referred to in this article is commonly known as PS_ON#, and the definition of PS_ON# is standardized by Intel Corporation. The aforementioned potential change of the start-stop signal 42 is only an embodiment proposed herein, and is not intended to limit this case.

As mentioned above, please refer to FIG. 2, the power supply 100 includes at least a power factor correction unit 10 and a startup control unit 11 connected to the power factor correction unit 10. The power factor correction unit 10 is commonly known as PFC (Power Factor Correction) ), the power factor correction unit 10 may be implemented by an interleaved power factor correction circuit, a bridgeless power factor correction circuit, or other circuits with power factor correction functions. Furthermore, the power factor correction unit 10 has a voltage stabilizing capacitor 12, a thermistor 13 connected in series with the voltage stabilizing capacitor 12, and a first switch 14 connected in parallel with the thermistor 13. Wherein, the first switch 14 may be a double carrier junction transistor (BJT), a field effect transistor (FET) or a metal oxide half field effect transistor (MOSFET). In an embodiment, the first switch 14 has a power transmission connected to the voltage stabilizing capacitor 12 The input terminal 141 is connected to the control terminal 142 of the startup control unit 11 and a first ground terminal 143. The thermistor 13 has a first terminal 131 connected to the power input terminal 141 and a first ground connection端143的第二端132. Furthermore, in one embodiment, the first switch 14 may be implemented by an N-type metal-oxide-semiconductor field effect transistor (N-MOSFET). The N-type metal-oxide-semiconductor field-effect transistor has a lower on-resistance, which can avoid the power supply The supplier 100 reduces efficiency due to it. On the other hand, since the first switch 14 is clamped by the thermistor 13, the withstand voltage of the first switch 14 need not be too high. In addition, the positions of the first switch 14 and the thermistor 13 can also be adjusted appropriately according to the circuit design. On the other hand, the activation control unit 11 is connected to the power factor correction unit 10 and controls the operation of the power factor correction unit 10. In addition, the activation control unit 11 may be implemented by a microchip (MCU) or other circuits that can achieve the same function. Furthermore, in the present invention, the start-up control unit 11 is further connected to the first switch 14 to control the power factor correction unit 10 while linking the first switch 14. Accordingly, the startup control unit 11 has a startup mode in which the power factor correction unit 10 is activated when the power supply 100 enters the startup mode and the first switch 14 is connected to short-circuit the thermistor 13 in conjunction, and a When the power supply 100 enters the shutdown mode, the power factor correction unit 10 is turned off and the first switch 14 is turned off so that the thermistor 13 can suppress the inrush current flowing into the power factor correction unit 10 in the shutdown mode.

Please refer to FIG. 1, FIG. 2 and FIG. 3, here is the first description of the boot mode, the operating time of the boot mode is an AC power source 300 to provide sufficient power to operate the power supply 100, and the power supply 100 The start-stop signal 42 received from the load 200 is at a low potential. When the power supply 100 receives that the start-stop signal 42 is at a low potential, the start-up control unit 11 can work based on a standing power (5VSB) generated by the normality of the power supply 100 when the power supply 100 starts up . After the power supply 100 is normally turned on, the startup control unit 11 can operate based on other power generated by the power supply 100, and is not limited to operating only with the standing power (5VSB). In addition, the activation control unit 11 activates the power factor correction unit 10 so that the power factor correction unit 10 starts to perform power factor correction on the received power, and outputs power required for operation to the subsequent stage circuit. On the other hand, the activation control unit 11 will activate the power factor correction unit 10 and simultaneously turn on the first switch 14 to short-circuit the thermistor 13. At this time, the main path of the current is shown as 40 in FIG. 3. . At this time, the thermistor 13 has no function during the normal operation of the power supply 100 to prevent the thermistor 13 from consuming power, resulting in reduced efficiency of the power supply 100.

Please also refer to FIG. 1, FIG. 2 and FIG. 4 to illustrate the shutdown mode. The working time of the shutdown mode is when the AC power source 300 cannot provide sufficient power for the power supply 100 to operate, or the power supply When the supplier 100 receives that the start-stop signal 42 from the load 200 is at a high potential (or open circuit), the start-up control unit 11 stops the work of the power factor correction unit 10 and turns off the first switch 14 in conjunction, so that The parallel branch to which the first switch 14 belongs enters an open state, so that current can only pass through the thermistor 13, and the current path at this time is shown as 41 in FIG. 4. It can be seen that the thermistor 13 is not short-circuited by the first switch 14, so that the thermistor 13 can reduce the inrush current entering the power factor correction unit 10 at the initial start of the power supply 100, To prevent the surge current from impacting the components of the power supply 100 and causing damage to the circuit.

Please refer to FIG. 2 again. According to the previous embodiment, in the present invention, to avoid multiple grounds in the circuit of the power supply 100, the circuit design is complicated and the system reliability is reduced. In one embodiment, the startup control unit 11 may further have a second ground terminal 111 connected to the first ground terminal 143 and making the startup control unit 11 and the power factor correction unit 10 form a common ground, and a second ground terminal 111 The working voltage input terminal 112 connected to the control terminal 142. To further illustrate, assume that the startup control unit 11 is implemented by a microchip (MCU), the second ground 111 is the ground pin (GND) of the microchip, and the operating voltage input 112 is the microchip Power supply pin (Vcc). Similarly, when the startup control unit 11 is implemented by a general circuit, the second ground 111 is the ground point of the general circuit (GND), the working voltage input terminal 112 is the power input point (Vcc) of the general circuit. According to this, the startup control unit 11 will operate with the standing power in the power-on mode, the standing power causes a voltage difference between the operating voltage input 112 and the second ground 111 to be driven The first switch 14 turns on the first switch 14. Furthermore, in addition to solving the aforementioned grounding problem in this embodiment, the solution disclosed in this embodiment further improves the reliability of the first switch 14 in system control, and does not require the use of additional peripheral circuits, thereby avoiding the increase in circuit implementation. cost.

Please refer to FIGS. 1 and 2 again. When the power factor correction unit 10 is not implemented as a bridgeless power factor correction circuit, the power supply 100 may include a rectification input unit disposed in front of the power factor correction unit 10 15. The rectification input unit 15 rectifies the AC power provided by the AC power source 300, and supplies the rectified power to the power factor correction unit 10. On the other hand, the power supply 100 may further have a power conversion unit 16 disposed behind the power factor correction unit 10. The power conversion unit 16 receives the power output from the power factor correction unit 10 and modulates the power to supply the power required by the load 200. The power modulation disclosed herein may be boost or buck. In addition, the power conversion unit 16 can be implemented by a flyback converter, a forward converter, a push-pull converter, a half-bridge converter, a full-bridge converter, or a circuit capable of direct current to direct current (DC/DC) .

The present invention has been described in detail above, but the above is only a preferred embodiment of the present invention, which cannot be used to limit the scope of implementation of the present invention, that is, any equivalent made in accordance with the scope of the patent application of the present invention Changes and modifications should still fall within the scope of the patent of the present invention.

100. . . . . . . . . . . . . Power supply 10． . . . . . . . . . . . . Power factor correction unit 11. . . . . . . . . . . . . Start the control unit 111. . . . . . . . . . . . . The second ground terminal 112. . . . . . . . . . . . . Working voltage input terminal 12. . . . . . . . . . . . . Voltage stabilizing capacitor 13. . . . . . . . . . . . . Thermistor 131. . . . . . . . . . . . . First end 132. . . . . . . . . . . . . Second end 14. . . . . . . . . . . . . The first switch 141. . . . . . . . . . . . . Power input 142. . . . . . . . . . . . . Control terminal 143. . . . . . . . . . . . . The first ground terminal 15. . . . . . . . . . . . . Rectifier input unit 16. . . . . . . . . . . . . Power conversion unit 300. . . . . . . . . . . . . AC power source

Claims (5)

A power supply with inrush current suppression, the power supply enters a start mode or a shutdown mode based on a potential of an on-off signal sent by a load, the power supply includes: a power factor correction unit, which has a stable Voltage capacitor, a thermistor in series with the voltage stabilizing capacitor and a first switch in parallel with the thermistor, the first switch has a power input terminal connected to the voltage stabilizing capacitor, a control terminal and a first ground terminal , The thermistor has a first terminal connected to the power input terminal, and a second terminal connected to the first ground terminal; and a start control unit connected to the control terminal of the first switch in the power factor correction unit , The startup control unit has a startup mode that activates the power factor correction unit and turns on the first switch to short-circuit the thermistor when the power supply enters the startup mode, and one enters the shutdown when the power supply enters In the mode, the power factor correction unit is turned off and the first switch is turned off so that the thermistor can suppress the inrush current flowing into the power factor correction unit. The power supply with surge current suppression according to claim 1, wherein the startup control unit has a second ground terminal connected to the first ground terminal so that the startup control unit and the power factor correction unit form a common ground And an operating voltage input terminal connected to the control terminal, when the startup control unit is in the boot mode, a voltage difference is formed between the operating voltage input terminal and the second ground terminal, the voltage difference makes the first switch conductive . The power supply device with surge current suppression according to claim 1 or 2, wherein the power supply device includes a rectification input unit provided at the front stage of the power factor correction unit. The power supply device with surge current suppression according to claim 3, wherein the power supply device includes a power conversion unit disposed at a subsequent stage of the power factor correction unit. The power supply with surge current suppression according to any one of claims 1 or 2, wherein the first switch may be a double carrier junction transistor, a field effect transistor, or a metal oxide half field effect transistor.

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