TWI628906B - Power supply and residual voltage discharging method - Google Patents

Abstract

A power supply includes a transformer winding, a switching circuit, a controller, and a filter circuit. The transformer windings are used to provide a first voltage. The switching circuit is electrically coupled to the transformer winding. The switching circuit includes a first switching unit and a second switching unit. The controller is electrically coupled to the first switch unit and the second switch unit. When the power supply is operating in the standby mode, the controller is configured to control the first switching unit and the second switching unit to provide a discharge path between the two ends of the transformer winding. When the power supply is operating in the operating mode, the controller is configured to control the switching circuit such that the switching circuit provides the second voltage according to the first voltage. The filter circuit is electrically coupled to the switching circuit for filtering the second voltage to provide an output voltage.

Description

Power supply and residual voltage discharge method

The present disclosure is directed to a power supply, and more particularly to a power supply that eliminates residual voltage.

When the existing power supply is in standby, there is still a residual voltage output at the output of the power supply due to the parasitic effect of the energy storage components such as inductance and capacitance inside the circuit. When the residual voltage is too large, it may cause malfunction of the back-end load circuit.

In order to avoid the normal operation of the system due to excessive residual voltage, the residual voltage of the power supply during standby should be lower than the rated specification. Therefore, how to reduce the residual voltage of the power supply with low cost and simplified circuit architecture is an important research topic in the field.

One aspect of the present disclosure is a power supply. The power supply includes a transformer winding, a switching circuit, a controller, and a filter circuit. The transformer windings are used to provide a first voltage. The switching circuit is electrically coupled to the transformer winding, wherein the switching circuit includes a first switching unit and a second switching unit. The controller is electrically coupled to the first switch unit and the second switch unit, wherein when the power supply is operated in the standby mode, the controller is configured to control the first switch unit and the second switch unit to provide a relationship between the two ends of the transformer winding The discharge path is used by the controller to control the switching circuit when the power supply is operated in the operating mode, so that the switching circuit supplies the second voltage according to the first voltage. The filter circuit is electrically coupled to the switching circuit for filtering the second voltage to provide an output voltage.

In some embodiments of the present disclosure, when the power supply is operated in the working mode, the controller is configured to control the first switch unit and the second switch unit to be respectively turned on during a first period and a second period. .

In some embodiments of the present disclosure, the first switch unit is electrically coupled between a first end of the transformer winding and a first input end of the filter circuit, and the second switch unit is electrically coupled to the second switch unit. Between a second end of the transformer winding and the first input end of the filter circuit, a center tap end of the transformer winding is electrically coupled to a second input end of the filter circuit.

In some embodiments of the present disclosure, the first switch unit is electrically coupled between a first end of the transformer winding and a first input end of the filter circuit, and the second switch unit is electrically coupled to the second switch unit. Between the first input end of the filter circuit and a second input end of the filter circuit, a second end of the transformer winding is electrically coupled to the second input end of the filter circuit.

In a partial embodiment of the present disclosure, a first end of the first switch unit is electrically coupled to a first end of the transformer winding, and a second end of the first switch unit is electrically coupled to the first end A second end of the second switch unit is electrically coupled to a second end of the transformer winding.

In some embodiments of the present disclosure, the first end of the transformer winding is electrically coupled to a first input end of the filter circuit, and the second end of the transformer winding is electrically coupled to one of the filter circuits. The second input.

In some embodiments of the present disclosure, the switching circuit further includes a third switching unit and a fourth switching unit, wherein the first switching unit is electrically coupled to a first end of the transformer winding and the filter circuit Between a first input end, the second switch unit is electrically coupled between the first end of the transformer winding and a second input end of the filter circuit, the third switch unit is electrically coupled to the Between a second end of the transformer winding and the first input end of the filter circuit, the fourth switch unit is electrically coupled between the second end of the transformer winding and the second input end of the filter circuit .

In some embodiments of the present disclosure, the switching circuit further includes a first diode and a second diode, wherein the first diode is electrically coupled to a first end of the transformer winding and the Between a first input end of the filter circuit, the second diode is electrically coupled between the first end of the transformer winding and a second input end of the filter circuit, and the first switch unit is electrically Between a second end of the transformer winding and the first input end of the filter circuit, the second switch unit is electrically coupled to the second end of the transformer winding and the second end of the filter circuit Between the inputs.

In some embodiments of the present disclosure, the filtering unit includes a first inductive unit and a second inductive unit, and a first end of the first inductive unit is electrically coupled to a first end of the transformer winding. A second end of the first inductive unit is electrically coupled to a first end of the second inductive unit, and a second end of the second inductive unit is electrically coupled to a second end of the transformer winding.

In some embodiments of the present disclosure, the filtering unit further includes a capacitor unit electrically coupled between the first end of the transformer winding and a first end of the capacitor unit, the first The second switch unit is electrically coupled between the second end of the transformer winding and the first end of the capacitor unit, and the second end of the first inductor unit is electrically coupled to a second end of the capacitor unit end.

In some embodiments of the present disclosure, the first switch unit and the second switch unit each include a transistor switch and a body diode, and the body diodes of the first switch unit and the second switch unit are opposite to each other. connection.

In some embodiments of the present disclosure, when the power supply is operating in the standby mode, the controller is configured to selectively output a first control signal and a second control signal according to the output voltage to control the first Opening and closing of a switch unit and the second switch unit.

In some embodiments of the present disclosure, when the output voltage is higher than a set level, the controller outputs the first control signal and the second control signal to simultaneously turn on the first switch unit and the second switch unit. .

In some embodiments of the present disclosure, when the output voltage is lower than a set level, the controller outputs a pulse width modulation signal as the first control signal and the second control signal.

In some embodiments of the present disclosure, when the output voltage is higher than a set level, the controller simultaneously controls opening and closing of the first switch unit and the second switch unit.

In some embodiments of the present disclosure, when the output voltage is lower than a set level, the controller controls only opening and closing of one of the first switch unit and the second switch unit.

Another aspect of the present disclosure is a residual voltage discharge method. The residual voltage discharge method includes: controlling a power supply to operate in a standby mode; and when the power supply is operated in the standby mode, controlling a first switch unit and a second through a controller in the power supply a switching unit for providing a discharge path between two ends of a transformer winding of the power supply, wherein the first switching unit and the second switching unit are selectively used when the power supply is operated in an operating mode The ground is turned on or off to provide an output voltage; and discharged through the discharge path to eliminate residual voltage on the transformer winding until the output voltage is less than a standard level.

In some embodiments of the present disclosure, the residual voltage discharge method further includes: detecting a voltage level of the output voltage; and outputting a first control signal through the controller when the output voltage is higher than a set level a second control signal for simultaneously turning on the first switching unit and the second switching unit; and when the output voltage is lower than the set level, outputting a pulse width modulation signal as the first control signal through the controller The second control signal controls the first switching unit and the second switching unit to be turned on or off.

In some embodiments of the present disclosure, the residual voltage discharge method further includes: adjusting the first control signal and the second control signal according to a voltage level of the output voltage when the output voltage is lower than the set level a duty cycle to control the first switching unit and the second switching unit to be turned on or off.

In some embodiments of the present disclosure, the residual voltage discharging method further includes: detecting a voltage level of the output voltage; and when the output voltage is higher than a set level, simultaneously controlling the first switching unit through the controller And opening and closing with the second switching unit; and when the output voltage is lower than the set level, controlling, by the controller, opening and closing of one of the first switching unit and the second switching unit, and transmitting the first A discharge path is provided by a switching unit and a body diode of the second switching unit.

The embodiments are described in detail below to better understand the aspects of the disclosure, but the embodiments are not intended to limit the scope of the disclosure, and the description of the structural operation is not used. In order to limit the order in which they are performed, any device that has been re-combined by the components, resulting in equal functionality, is covered by this disclosure. In addition, according to industry standards and practices, the drawings are only for the purpose of assisting the description, and are not drawn according to the original size. In fact, the dimensions of the various features may be arbitrarily increased or decreased for convenience of explanation. In the following description, the same elements will be denoted by the same reference numerals for explanation.

The terms used in the entire specification and the scope of the patent application, unless otherwise specified, generally have the ordinary meaning of each term used in the field, the content disclosed herein, and the particular content. Certain terms used to describe the disclosure are discussed below or elsewhere in this specification to provide additional guidance to those skilled in the art in the description of the disclosure.

In addition, the terms "including", "including", "having", "containing", and the like, as used herein, are all open terms, meaning "including but not limited to". Further, "and/or" as used herein includes any one or combination of one or more of the associated listed items.

As used herein, when an element is referred to as "connected" or "coupled", it may mean "electrically connected" or "electrically coupled". "Connected" or "coupled" can also be used to indicate that two or more components operate or interact with each other. In addition, although the terms "first", "second", and the like are used herein to describe different elements, the terms are used only to distinguish the elements or operations described in the same technical terms. The use of the term is not intended to be a limitation or a

In the various embodiments, similar elements are denoted by the same reference numerals for the sake of understanding, and the specific principles of the similar elements have been described in detail in the previous paragraphs, and if they are not necessary to have a cooperative relationship with other elements, it is necessary to introduce them. .

Please refer to Figure 1. FIG. 1 is a schematic diagram of a power supply 100 according to some embodiments of the present disclosure. As shown in FIG. 1, in some embodiments, the secondary side of the power supply 100 includes a transformer winding 120, a switching circuit 140, a controller 160, and a filter circuit 180. Specifically, the primary side circuit of the power supply 100 can select various circuits such as a half bridge circuit structure, a push-pull circuit structure, and a full bridge circuit structure according to actual needs, so as to realize different types of isolated high frequency DC power conversion. Circuit.

The transformer winding 120 may be a secondary winding of the secondary side of the power supply 100 for providing a voltage Vs in response to a change in the primary side voltage on the primary winding. As shown in the figures, in some embodiments the transformer windings 120 can be center-tapped windings including a first end, a second end, and a center tap end.

The switching circuit 140 includes a switching unit 142 and a switching unit 144. For example, the switching unit 142 and the switching unit 144 can transmit, for example, a Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET) or a Bipolar Junction Transistor (BJT). Various semiconductor device switches are implemented, but the disclosure is not limited thereto. Structurally, the switching circuit 140 is electrically coupled to the transformer winding 120. Specifically, in the embodiment shown in FIG. 1 , the switch unit 142 is electrically coupled to the first end of the transformer winding 120 (eg, the striking end) and the first input end of the filter circuit 180 (eg, the negative input) Between the ends). The switch unit 144 is electrically coupled between the second end of the transformer winding 120 (eg, the non-tapping end) and the first input end of the filter circuit 180. The center tap end of the transformer winding 120 is electrically coupled to the second input end of the filter circuit 180 (eg, the positive input terminal).

The controller 160 is electrically coupled to the switch unit 142 and the switch unit 144 in the switching circuit 140. The controller 160 is configured to selectively control the switching unit 142 and the switching unit 144 to be turned on or off to implement the operation of the power supply 100 in conjunction with other circuit units.

When the power supply 100 is operated in the operating mode, the controller 160 is configured to control the switching circuit 140 such that the switching circuit 140 outputs the voltage V1 to the filter circuit 180 according to the voltage Vs.

For example, when the secondary voltage Vs is positive, the tap end of the transformer winding 120 has a positive potential, the switching unit 144 is turned on, and current flows through the switching unit 144 to the filter circuit 180. On the other hand, when the secondary voltage Vs changes to negative in response to the primary voltage change, the non-inrush terminal of the transformer winding 120 has a positive potential, the switching unit 142 is turned on, and the current flows through the switching unit 142 to the filter circuit 180.

In other words, when the power supply 100 is operated in the operating mode, the controller 160 is configured to control the switching unit 142 and the switching unit 144 to be respectively turned on during the first period and the second period in a complete switching cycle, so that the switching circuit 140 is connected to the transformer. The secondary voltage Vs supplied from the winding 120 is rectified and the rectified voltage V1 is output to the filter circuit 180.

Structurally, the filter circuit 180 is electrically coupled to the switching circuit 140 for filtering the voltage V1 output by the switching circuit 140 to provide an output voltage Vo. In some embodiments, the filter circuit 180 can be implemented by a capacitor and an inductor, the detailed circuit of which will be further described in subsequent paragraphs.

In this way, through the cooperative operation of the transformer winding 120, the switching circuit 140, the controller 160, and the filter circuit 180, the secondary circuit of the power supply 100 can be rectified and filtered in the working mode, and matched with the switch in the primary circuit. The opening and closing operation of the component provides a DC output voltage Vo with an appropriate level to the output load terminal.

In some embodiments, when the power supply 100 does not need to supply the voltage Vo to the load, the power supply 100 can be switched from the operating mode to the standby mode to save unnecessary line loss. However, in the standby mode, the power supply 100 still has a residual voltage Vo at the output of the power supply 100 due to the parasitic effect of the energy storage components such as inductance and capacitance inside the circuit loop. If the residual voltage Vo is too large, the back-end system may not work properly. Therefore, in the standby mode, the residual output voltage Vo of the power supply 100 needs to be lower than the rated specification.

In order to reduce the residual output voltage Vo, in some embodiments, when the power supply 100 is operating in the standby mode, the controller 160 controls the switching unit 142 and the switching unit 144 to provide a discharge path between the ends of the transformer winding 120. In this way, the voltage derived from the parasitic inductance and parasitic capacitance remaining in the transformer winding 120 can be eliminated through the discharge path.

For example, the controller 160 can control both the switching unit 142 and the switching unit 144 to be turned on at the same time. In this way, the first end and the second end of the transformer winding 120 can be electrically coupled to each other through the switch unit 142 and the switch unit 144. Thereby, the energy generated by the parasitic inductance and the parasitic capacitance inside the transformer winding 120 cannot be transmitted to the output end of the power supply 100. As a result, the output voltage Vo can be lower than the rated specification.

Please refer to Figure 2. FIG. 2 is a schematic diagram of a power supply 100 according to some embodiments of the present disclosure. As shown in FIG. 2, in some embodiments, the switching unit 142 and the switching unit 144 may each include a transistor switch and a body diode on which the body is parasitic. The switching unit 142 and the body diodes in the switching unit 144 are connected to each other in reverse.

For example, the switching unit 142 and the switching unit 144 may be N-type metal oxide semiconductor field effect transistors. The anode end of the body diode is the source terminal of the transistor, and the cathode end of the body diode is the 汲 terminal of the transistor. In other embodiments, the switching unit 142 and the switching unit 144 may also be provided with independent diode units connected across the source terminal and the drain terminal of the transistor to provide a reverse current return path.

In the embodiment shown in FIG. 2, the controller 160 is configured to output the control signals CS1, CS2 to the gate terminals of the transistors in the switching unit 142 and the switching unit 144, respectively, to control the on and off of the transistor switches. For example, when the control signal CS1 has a uniform level (eg, a high level), the switching unit 142 is turned on. When the control signal CS1 has a disable level (eg, a low level), the switch unit 142 is turned off. The control signal CS2 controls the operation of the switch unit 144 to be similar to the operation of the control signal CS1 to control the switch unit 142, and thus will not be described herein.

As shown in FIG. 2, in some embodiments, the filter circuit 180 includes capacitors C1, C2 and an inductor L1. The first end of the capacitor C1 is electrically coupled to the first input end of the filter circuit 180, and the second end of the capacitor C1 is electrically coupled to the second input end of the filter circuit 180. The first end of the inductor L1 is electrically coupled to the first end of the capacitor C1, and the second end of the inductor L1 is electrically coupled to the first end of the capacitor C2. The first end of the capacitor C2 is electrically coupled to the first output end of the filter circuit 180, and the second end of the capacitor C2 is electrically coupled to the second output end of the filter circuit 180.

In this way, the capacitors C1, C2 and the inductor L1 form an LC-π type filter circuit to filter the voltage V1 outputted by the switching circuit 140, and provide an output voltage Vo across the output capacitor C2. It should be noted that the filter circuit 180 illustrated in FIG. 2 is only one of the possible embodiments of the present disclosure, and is not intended to limit the disclosure. In other embodiments, the filter circuit 180 can also be implemented by various types of inductive filter circuits, capacitor filter circuits, or inductor-capacitor filter circuits.

Please refer to Figure 3. FIG. 3 is a schematic diagram of a power supply 100 according to other partial embodiments of the present disclosure. In the present embodiment, the switch unit 142 is electrically coupled between the first end of the transformer winding 120 (eg, the striking end) and the positive input terminal of the filter circuit 180. The switch unit 144 is electrically coupled between the second end of the transformer winding 120 (eg, the non-tapping end) and the positive input of the filter circuit 180. The center tap end of the transformer winding 120 is electrically coupled to the negative input terminal of the filter circuit 180. When the power supply 100 operates in the operating mode, when the secondary voltage Vs is positive, the switching terminal of the transformer winding 120 has a positive potential, the switching unit 142 is turned on, and current flows through the switching unit 142 to the filter circuit 180. On the other hand, when the secondary side voltage Vs changes to negative in response to the primary side voltage change, the non-tapping end of the transformer winding 120 has a positive potential, the switching unit 144 is turned on, and the current flows through the switching unit 144 to the filter circuit 180. The rest of the specific operations are similar to the embodiment shown in FIG. 2, and thus will not be described again.

Please refer to Figure 4. FIG. 4 is a schematic diagram of a power supply 100 according to other partial embodiments of the present disclosure. In some embodiments, the power supply 100 can be a forward conversion circuit architecture. Structurally, the switching unit 142 of the switching circuit 140 of the secondary side is electrically coupled to the first end of the transformer winding 120 (eg, the striking end) and the first input end of the filter circuit 180 (eg, the positive terminal) between. The switch unit 144 is electrically coupled between the first input end of the filter circuit 180 and the second input end of the filter circuit 180. The second end of the transformer winding 120 (eg, the non-tapping end) is electrically coupled to the second input of the filter circuit 180.

When the power supply 100 operates in the operating mode, when the secondary voltage Vs is positive, the controller 160 controls the switching unit 142 to be turned on, and the switching unit 144 is turned off, so that the energy is transmitted from the transformer winding 120 via the switching unit 142 and the filter circuit 180. The inductor L1 in the output is the output voltage Vo to the output. On the other hand, when the polarity of the secondary voltage Vs is reversed, the controller 160 controls the switching unit 142 to be turned off, and the switching unit 144 is turned on, so that the inductor L1, the capacitor C1 and the switching unit 144 form a loop, and the inductor L1 and the capacitor C1 are turned on. The energy stored in is supplied to the load in the form of an output voltage Vo.

In other words, in the present embodiment, the inductor L1 and the capacitor C1 in the filter circuit 180 are used as an energy storage element in addition to being used as a low-pass filter circuit.

Similar to the previous embodiment, in order to reduce the residual output voltage Vo, the controller 160 can control both the switching unit 142 and the switching unit 144 to be turned on at the same time. In this way, the first end and the second end of the transformer winding 120 can be electrically coupled to each other through the switch unit 142 and the switch unit 144. Thereby, the energy generated by the parasitic inductance and the parasitic capacitance inside the transformer winding 120 cannot be transmitted to the output end of the power supply 100. As a result, the output voltage Vo can be lower than the rated specification.

As described in the above paragraphs, in various embodiments, the switching circuit 140 can rectify the secondary voltage Vs through different circuit forms. Please refer to Figures 5 to 8. 5 to 8 are schematic views of a power supply 100 according to other partial embodiments of the present disclosure. In various embodiments of Figures 5 through 8, the switching circuit 140 can be a variety of full bridge rectifier circuits or current doubler rectifier circuits.

For example, in the embodiment shown in FIG. 5, the switching circuit 140 further includes a switching unit 146 and a switching unit 148 as compared with the embodiment shown in FIG. The switch unit 142 is electrically coupled between the first end of the transformer winding 120 (eg, the striking end) and the first input end of the filter circuit 180. The switch unit 144 is electrically coupled between the first end of the transformer winding 120 and the second input of the filter circuit 180. The switch unit 146 is electrically coupled between the second end of the transformer winding 120 (eg, the non-tap end) and the first input of the filter circuit 180. The switch unit 148 is electrically coupled between the second end of the transformer winding 120 and the second input of the filter circuit 180.

In this way, the switching circuit 140 can perform full-bridge rectification of the secondary voltage Vs by the controller 160 correspondingly controlling the opening and closing of the switching units 142 to 148.

In the embodiment shown in Fig. 6, the semiconductor switch on the arm of one arm of the full bridge circuit can be replaced with the diodes D1, D2 as compared with the embodiment shown in Fig. 5. Specifically, the diode D1 is electrically coupled between the first end of the transformer winding 120 (eg, the striking end) and the first input end of the filter circuit 180. The diode D2 is electrically coupled between the first end of the transformer winding 120 and the second input of the filter circuit 180. The switch unit 142 is electrically coupled between the second end of the transformer winding 120 (eg, the non-tapping end) and the first input end of the filter circuit 180. The switch unit 144 is electrically coupled between the second end of the transformer winding 120 and the second input of the filter circuit 180.

In this way, the switching circuit 140 can perform full-bridge rectification of the secondary voltage Vs by the controller 160 correspondingly controlling the opening and closing of the switching units 142 and 144.

In the embodiment shown in FIG. 7 , the first end of the switch unit 142 is electrically coupled to the first end of the transformer winding 120 (eg, the striking end). The second end of the switch unit 142 is electrically coupled to the first end of the switch unit 144. The second end of the switch unit 144 is electrically coupled to the second end of the transformer winding (eg, the non-tapping end). The first end of the transformer winding 120 is electrically coupled to the first input of the filter circuit 180. The second end of the transformer winding 120 is electrically coupled to the second input of the filter circuit 180.

The filter circuit 180 includes inductors L1, L2 and a capacitor C1. The inductor L1 is electrically coupled between the first input of the filter circuit 180 and the first end of the capacitor C1. The inductor L2 is electrically coupled between the second input of the filter circuit 180 and the first end of the capacitor C1. The second end of the capacitor C1 is electrically coupled to the second end of the switch unit 142 and the first end of the switch unit 144.

In this way, by the controller 160 correspondingly controlling the opening and closing of the switch units 142, 144, the switching circuit 140 can be used to rectify the secondary voltage Vs with the filter circuit 180.

In the embodiment shown in FIG. 8, the first end of the inductor L1 is electrically coupled to the first end of the transformer winding 120 (eg, the striking end), as compared with the embodiment shown in FIG. The second end of the inductor L1 is electrically coupled to the first end of the inductor L2. The second end of the inductor L2 is electrically coupled to the second end of the transformer winding 120 (eg, the non-tapping end).

The switch unit 142 is electrically coupled between the first end of the transformer winding 120 and the first end of the capacitor C1. The switch unit 144 is electrically coupled between the second end of the transformer winding 120 and the first end of the capacitor C1. The second end of the inductor L1 and the first end of the inductor L2 are electrically coupled to the second end of the capacitor C1.

In other words, in some embodiments, the inductors L1, L2 and the capacitor C1 in the filter circuit 180 can be correspondingly set according to the actual requirements of the circuit, so as to cooperate with the switching circuit 140 to rectify and filter the secondary voltage Vs to provide the output voltage Vo. Therefore, the circuits in the above various embodiments are merely examples and are not intended to limit the disclosure.

Please refer to Figure 9. FIG. 9 is a schematic diagram of a controller 160 according to some embodiments of the present disclosure. As shown in FIG. 9, in some embodiments, the controller 160 includes a microprocessor unit 162 and a drive unit 164. The microprocessor unit 162 can receive the system signal SS from the system side to selectively control the power supply 100 to operate in an active mode or a standby mode. The driving unit 164 is electrically coupled to the microprocessor unit 162, and receives the reference voltage VDD and the signals OutA, OutB from the microprocessor unit 162, and outputs the driving signals SR_AG, SR_BG according to the signals OutA, OutB to cooperate with the controller 160. A driving circuit composed of a resistor, a diode, and a transistor outputs control signals CS1 and CS2 to the switching units 142 and 144.

In addition, in some embodiments, the microprocessor unit 162 can also detect the magnitude of the output voltage Vo through the feedback line. Thereby, when the power supply 100 operates in the standby mode, the controller 160 can selectively output the control signals CS1, CS2 according to the output voltage Vo to control the opening and closing of the switching units 142, 144, respectively.

Please refer to Figures 10A through 10C together. 10A to 10C are waveform diagrams of control signals CS1 and CS2, respectively, according to some embodiments of the present disclosure. For convenience and clarity of description, the control signals CS1 and CS2 shown in FIGS. 10A to 10C are described in conjunction with the embodiment shown in FIG. 9, but are not limited thereto, and any one skilled in the art may Various changes and retouchings can be made without departing from the spirit and scope of the present disclosure.

As shown in FIG. 10A to FIG. 10C, the controller 160 can output a Pulse Width Modulation (PWM) signal as the control signals CS1 and CS2, and control the discharge path by adjusting the duty cycle of the control signals CS1 and CS2. During the conduction period.

For example, in some embodiments, when the output voltage Vo is higher than the set level, the controller 160 may output the control signals CS1, CS2, and simultaneously turn on the switching unit 142 and the switching unit 144 in the entire cycle, so that the entire cycle The discharge path is continuously turned on to reduce the residual voltage at a faster rate.

On the other hand, when the output voltage Vo is lower than the set level, the controller 160 can output the pulse width modulation signal as shown in FIG. 10A as the control signals CS1, CS2, so that the switching unit 142 and the switching unit are The discharge path formed by 144 is turned on for discharging during a part of the entire period.

In addition, when the output voltage Vo is high, the controller 160 can increase the duty cycle of the control signals CS1, CS2 by feedback control. Conversely, when the output voltage Vo is low, the controller 160 can reduce the duty cycle of the control signals CS1, CS2 by feedback control. Thereby, through the above control, the power loss of the power supply 100 as a whole can be reduced while satisfying the requirements of the output residual voltage specification.

As shown in FIG. 10B, in some embodiments, the control signals CS1, CS2 are at the enable level in the first half cycle and the second half cycle, respectively. Specifically, when the control signal CS1 turns on the transistor switch in the switching unit 142, the body diode in the switching unit 144 can provide a current path. In this way, even if the control signal CS2 is at the disable level, the switch unit 142 and the switch unit 144 can form a discharge path for discharging. Similarly, when the control signal CS2 turns on the transistor switch in the switch unit 144, the body diode in the switch unit 142 can provide a current path to provide a discharge path for discharging when the control signal CS1 is at the disable level.

In addition, in some embodiments, the controller 160 may also select to simultaneously control the two sets of switch units 142, 144 or only one of the switch units 142, 144 according to the output voltage Vo.

For example, in some embodiments, when the output voltage Vo is higher than the set level, the controller 160 can simultaneously control the opening and closing of the switching unit 142 and the switching unit 144 to accelerate the residual voltage discharge. In contrast, when the output voltage Vo is lower than the set level, the controller 160 can output the pulse width modulation signal as shown in FIG. 10C, and output only one set of control signals CS1 to control the switch unit 142 to lower the control switch. Losses generated by units 142, 144.

It should be noted that the controller 160 may also output only one set of control signals CS2 to control the switch unit 144. In other words, the controller 160 can output only one set of the control signal CS1 or the control signal CS2 to control the opening and closing of one of the switch unit 142 and the switch unit 144.

In this way, through the above control method, the controller 160 can reduce the power loss of the power supply 100 as a whole while satisfying the residual voltage specification of the output terminal, so that the loss of the power supply 100 operating in the standby mode is reduced. A more energy efficient, low power power supply 100 is obtained.

Please refer to Figure 11. 11 is a flow chart of a residual voltage discharge method 900 in accordance with some embodiments of the present disclosure. For convenience and clarity of description, the following residual voltage discharge method 900 is described with reference to the embodiments shown in FIGS. 1 to 10, but is not limited thereto, and any person skilled in the art can avoid the disclosure. Within the spirit and scope, when you can make a variety of changes and retouching. As shown in FIG. 11, the residual voltage discharge method 900 includes steps S910, S920, and S930.

First, in step S910, when the power supply 100 does not need to supply the output voltage Vo, the control power supply 100 operates in the standby mode.

Next, in step S920, when the power supply 100 operates in the standby mode, the switch unit 142 and the switch unit 144 are controlled by the controller 160 in the power supply 100 to provide the two ends of the transformer winding 120 in the power supply 100. The discharge path between.

In particular, as described in the previous embodiments, the switching units 142, 144 are used to selectively turn "on" or "off" when the power supply 100 is operating in an operating mode to provide an output voltage Vo.

Finally, in step S930, the discharge path is discharged to eliminate the residual voltage on the transformer winding 120 until the output voltage Vo is less than the target standard. In this way, the specification of the residual voltage at the output can be met.

In addition, in some embodiments, the residual voltage discharge method 900 further includes detecting a voltage level of the output voltage Vo, and adjusting the control signals CS1 and CS2 according to the output voltage Vo.

In some embodiments, when the output voltage Vo is higher than the set level, the controller 160 outputs the control signals CS1, CS2 to simultaneously turn on the switching unit 142 and the switching unit 144. When the output voltage Vo is lower than the set level, the controller 160 outputs a pulse width modulation signal as the control signals CS1, CS2.

Specifically, when the output voltage Vo is lower than the set level, the controller 160 can adjust the duty cycle of the control signals CS1 and CS2 according to the voltage level of the output voltage Vo to control the switch unit 142 and the switch unit 144 to be turned on or off. .

In addition, in other embodiments, when the output voltage Vo is higher than the set level, the controller 160 simultaneously controls the opening and closing of the switch unit 142 and the switch unit 144. When the output voltage Vo is lower than the set level, the controller 160 controls the opening and closing of one of the switching unit 142 and the switching unit 144, and provides a discharge path through the switching unit 142 and the body diode of the switching unit 144.

Those skilled in the art can directly understand how this residual voltage discharge method 900 is based on the power supply 100 of the various different embodiments described above to perform such operations and functions, and thus will not be described again.

While the methods disclosed are shown and described herein as a series of steps or events, it is understood that the order of the steps or events shown should not be construed as limiting. For example, some of the steps may occur in a different order and/or concurrently with other steps or events other than those illustrated or/or described herein. In addition, not all of the steps shown herein are required in the practice of one or more aspects or embodiments described herein. Moreover, one or more steps herein may also be performed in one or more separate steps and/or stages.

In summary, in various embodiments of the present disclosure, the semiconductor component in the secondary circuit of the power supply can be passed through, and the residual voltage remaining in the power supply is eliminated when the power supply has no power output. Exhausted. In addition, through the control method of the present disclosure, the semiconductor element that is idle in the standby mode can be utilized without any additional components, and the controller can perform corresponding control to achieve the effect of eliminating the residual voltage.

It should be noted that the features and circuits in the various drawings, embodiments, and embodiments of the present disclosure may be combined with each other without conflict. The circuit illustrated in the drawings is for illustrative purposes only, and is simplified for simplicity and ease of understanding, and is not intended to limit the disclosure.

The present disclosure has been disclosed in the above embodiments, and is not intended to limit the disclosure, and the present disclosure may be variously modified and retouched without departing from the spirit and scope of the present disclosure. The scope of protection of the content is subject to the definition of the scope of the patent application.

100‧‧‧Power supply

120‧‧‧Transformer winding

140‧‧‧Switching circuit

142, 144, 146, 148‧‧ ‧ switch unit

160‧‧‧ Controller

162‧‧‧Microprocessor unit

164‧‧‧ drive unit

180‧‧‧Filter circuit

900‧‧‧Residual voltage discharge method

S910, S920, S930‧‧‧ steps

L1, L2‧‧‧ inductance

C1, C2‧‧‧ capacitor

D1, D2‧‧‧ diode

Vs, V1, Vo, VDD‧‧‧ voltage

CS1, CS2‧‧‧ control signals

OutA, OutB‧‧‧ signals

SR_AG, SR_BG‧‧‧ drive signals

SS‧‧‧ system signal

FIG. 1 is a schematic diagram of a power supply according to a first embodiment of the present disclosure. FIG. 2 is a schematic diagram of a power supply according to a first embodiment of the present disclosure. FIG. 3 is a schematic diagram of a power supply according to a second embodiment of the present disclosure. FIG. 4 is a schematic diagram of a power supply according to a third embodiment of the present disclosure. 5 to 8 are schematic views of a power supply device according to other embodiments of the present disclosure. FIG. 9 is a schematic diagram of a controller according to an embodiment of the present disclosure. 10A to 10C are waveform diagrams of control signals according to some embodiments of the present disclosure. FIG. 11 is a flow chart of a residual voltage discharge method according to an embodiment of the present disclosure.

Claims (20)

A power supply, comprising: a transformer winding for providing a first voltage; a switching circuit electrically coupled to the transformer winding, wherein the switching circuit comprises a first switching unit and a second switching unit; The controller is electrically coupled to the first switch unit and the second switch unit, wherein the controller is configured to control the first switch unit and the second switch unit when the power supply is operated in a standby mode Simultaneously conducting to provide a discharge path between the two ends of the transformer winding. When the power supply is operated in an operating mode, the controller is configured to control the switching circuit, so that the switching circuit provides a first voltage according to the first voltage. a second voltage; and a filter circuit electrically coupled to the switching circuit for filtering the second voltage to provide an output voltage. The power supply device of claim 1, wherein the controller is configured to control the first switch unit and the second switch unit in a first period and a first time when the power supply is operated in the working mode Conducted during the second period. The power supply device of claim 1, wherein the first switch unit is electrically coupled between a first end of the transformer winding and a first input end of the filter circuit, and the second switch unit is electrically Between a second end of the transformer winding and the first input end of the filter circuit, a center tap end of the transformer winding is electrically coupled to a second input end of the filter circuit. The power supply device of claim 1, wherein the first switch unit is electrically coupled between a first end of the transformer winding and a first input end of the filter circuit, and the second switch unit is electrically A second end of the transformer winding is electrically coupled to the second input end of the filter circuit. The second input end of the filter circuit is electrically coupled to the second input end of the filter circuit. The power supply of claim 1, wherein a first end of the first switch unit is electrically coupled to a first end of the transformer winding, and a second end of the first switch unit is electrically coupled A second end of the second switch unit is electrically coupled to a second end of the transformer winding. The power supply of claim 5, wherein the first end of the transformer winding is electrically coupled to a first input end of the filter circuit, and the second end of the transformer winding is electrically coupled to the filter a second input of the circuit. The power supply device of claim 1, wherein the switching circuit further includes a third switching unit and a fourth switching unit, wherein the first switching unit is electrically coupled to a first end of the transformer winding and the Between a first input end of the filter circuit, the second switch unit is electrically coupled between the first end of the transformer winding and a second input end of the filter circuit, the third switch unit is electrically coupled Connected to a second end of the transformer winding and the filter circuit The fourth switching unit is electrically coupled between the second end of the transformer winding and the second input of the filter circuit. The power supply device of claim 1, wherein the switching circuit further comprises a first diode and a second diode, wherein the first diode is electrically coupled to a first of the transformer winding The second diode is electrically coupled between the first end of the transformer winding and a second input end of the filter circuit, and the first switch is coupled to a first input end of the filter circuit, the first switch The unit is electrically coupled between a second end of the transformer winding and the first input end of the filter circuit, the second switch unit is electrically coupled to the second end of the transformer winding and the filter circuit Between the second inputs. The power supply device of claim 1, wherein the filtering unit comprises a first inductive unit and a second inductive unit, and a first end of the first inductive unit is electrically coupled to a first end of the transformer winding The second end of the second inductive unit is electrically coupled to a first end of the second inductive unit, and the second end of the second inductive unit is electrically coupled to a second end of the transformer winding end. The power supply device of claim 9, wherein the filtering unit further comprises a capacitor unit electrically coupled between the first end of the transformer winding and a first end of the capacitor unit The second switch unit is electrically coupled between the second end of the transformer winding and the first end of the capacitor unit, and the second end of the first inductor unit is electrically coupled to the capacitor unit A second end. The power supply device of claim 1, wherein the first switch unit and the second switch unit each comprise a transistor switch and a body diode, and the body diode of the first switch unit and the second switch unit Connected to each other in reverse. The power supply of claim 1, wherein the controller is configured to selectively output a first control signal and a second control signal according to the output voltage when the power supply is operated in the standby mode. Controlling opening and closing of the first switching unit and the second switching unit. The power supply device of claim 12, wherein when the output voltage is higher than a set level, the controller outputs the first control signal and the second control signal to simultaneously turn on the first switch unit and the first Two switch units. The power supply of claim 12, wherein when the output voltage is lower than a set level, the controller outputs a pulse width modulation signal as the first control signal and the second control signal. The power supply of claim 12, wherein the controller simultaneously controls opening and closing of the first switching unit and the second switching unit when the output voltage is higher than a set level. The power supply of claim 12, wherein When the output voltage is lower than a set level, the controller only controls opening and closing of one of the first switch unit and the second switch unit. A residual voltage discharge method includes: controlling a power supply to operate in a standby mode; and controlling a first switch unit and a controller through a controller in the power supply when the power supply is operated in the standby mode The second switching unit is simultaneously turned on to provide a discharge path between the two ends of a transformer winding of the power supply, wherein the first switching unit and the second switching unit are configured to operate in a working mode of the power supply Selectively turning on or off to provide an output voltage; and discharging through the discharge path to eliminate residual voltage on the transformer winding until the output voltage is less than a standard level. The residual voltage discharge method of claim 17, further comprising: detecting a voltage level of the output voltage; and when the output voltage is higher than a set level, outputting a first control signal and a first a second control signal for simultaneously turning on the first switch unit and the second switch unit; and when the output voltage is lower than the set level, outputting a pulse width modulation signal through the controller as the first control signal and the first The second control signal controls the first switch unit and the second switch unit to be turned on or off. The residual voltage discharge method as described in claim 18, The method includes: when the output voltage is lower than the set level, adjusting a duty cycle of the first control signal and the second control signal according to a voltage level of the output voltage, to control the first switch unit and the second switch The unit is turned on or off. The residual voltage discharge method of claim 17, further comprising: detecting a voltage level of the output voltage; and when the output voltage is higher than a set level, simultaneously controlling the first switch unit and the Opening and closing of the second switching unit; and when the output voltage is lower than the set level, controlling, by the controller, opening and closing of one of the first switching unit and the second switching unit, and transmitting the first switch The discharge path is provided by the unit and the body diode in the second switching unit.