TWI865051B - Power supply providing synchronous rectification control with high resonant efficiency - Google Patents

Abstract

A power supply includes an active power factor correction circuit, a resonant conversion circuit, a voltage detecting circuit, and a control circuit. The active power factor correction circuit and the resonant conversion circuit convert an AC voltage into an output voltage for driving a load. The voltage detecting circuit monitors the status of the output voltage. When the output voltage does not exceeds a reference voltage, the control circuit instructs the resonant conversion circuit to operate with full synchronous rectification. When the output voltage exceeds the reference voltage, the control circuit instructs the resonant conversion circuit to operate with complimentary synchronous rectification. There present power supply provides synchronous rectification control with high resonant efficiency.

Description

Power supply with synchronous rectification control and high resonance efficiency

The present invention relates to a power supply, in particular to a power supply with synchronous rectification control and high resonance efficiency.

Different components in a computer system require different operating voltages, so power supplies are commonly used to convert AC indoor power into direct current (DC) to drive different components through transformation, rectification and filtering. With the rise of environmental awareness, countries have energy-saving specifications for consumer electronic products, office equipment, home appliances and external power supplies. For example, the US Energy Star is a certification program jointly sponsored by the US Department of Energy and the Environmental Protection Agency. It has clear definitions and energy-saving specification requirements for power supplies with different rated output power in various states and under different load operations.

For example, for power supplies with an output power greater than 70W and their overall system configuration, the US Energy Star stipulates that the rated power factor must be greater than 0.9. Therefore, the design architecture of high-power power supplies is usually divided into a boost-type front-stage circuit and a buck-type back-stage circuit. The front-stage circuit of a high-power power supply can be a boost-type power factor corrector, which is responsible for improving the power factor of the AC power supply end; the back-stage circuit of a high-power power supply can use a buck-type inductor-inductor-capacitor (LCC) resonant converter, which is responsible for converting the high voltage (e.g. 400V) output by the boost-type power factor corrector into a low voltage (e.g. 19.5V) to supply load devices such as laptops.

When the power switch is hard switched, the product of its cross-voltage and the current passing through the power switch will cause switching loss of the power switch, resulting in reduced overall circuit efficiency. A resonant converter is a switching power supply that uses resonance to convert electrical energy, and includes a resonant circuit formed by an inductor and a capacitor. When the power switch is switched, the LLC resonance generated by the inductor and capacitor is used to convert the voltage at both ends of the power switch into a sinusoidal voltage or current to achieve flexible switching of zero voltage or zero current, thereby solving the problems caused by high-frequency switching. Therefore, a power supply with synchronous rectification control and high resonance efficiency is needed.

The present invention provides a power supply with synchronous rectification control and high resonance efficiency, which includes an input terminal for receiving an AC voltage, an output terminal for outputting an output voltage, a boost type active power factor correction circuit, a resonance conversion circuit, a voltage detection circuit, and a control circuit. The boost type active power factor correction circuit includes a first switch for converting the AC voltage into a DC voltage, and then converting the DC voltage into a first pulsed DC voltage. The resonance conversion circuit is used to convert the first pulsed DC voltage into the output voltage, and includes a transformer and second to seventh switches. The transformer is used to induce the first pulsed DC voltage from a primary side to a secondary side to supply the output voltage, and includes a primary side winding and first to fourth synchronous rectifier windings. The second switch and the third switch are arranged on the primary side to control the operation of the resonant circuit. The fourth switch selectively transmits the energy stored in the first synchronous rectifier winding to the output end to provide a second pulsed DC voltage. The fifth switch is arranged to selectively transmit the energy stored in the second synchronous rectifier winding to the output end to provide the second pulsed DC voltage. The sixth switch selectively transmits the energy stored in the third synchronous rectifier winding to the output end to provide a third pulsed DC voltage. The seventh switch selectively transmits the energy stored in the fourth synchronous rectifier winding to the output terminal to provide the third pulsed DC voltage. The voltage detection circuit is used to detect the state of the output voltage and output a corresponding judgment voltage. When the value of the output voltage is determined to be less than a reference voltage according to the judgment voltage, the control circuit outputs fourth to seventh control signals with enable potentials to turn on the fourth to seventh switches respectively. When the output voltage is determined to be not less than the reference voltage according to the determination voltage, the control circuit outputs the fourth to seventh control signals in a first cycle to turn on the fifth and seventh switches and turn off the fourth and sixth switches, and outputs the fourth to seventh control signals in a second cycle to turn off the fifth and seventh switches and turn on the fourth and sixth switches.

10: Boost type active power factor correction circuit

20: Resonance conversion circuit

30: Voltage detection circuit

32: Error amplifier

34:Logic unit

40: Control circuit

100: Power supply

TR: Transformer

PWMIC1, PWMIC2: pulse width modulation integrated circuit

SRIC1, SRIC2: Synchronous rectification switch control integrated circuit

NP: Primary side winding set and number of turns

NS1: First synchronous rectifier winding and turns

NS2: Second synchronous rectifier winding and turns

NS3: The third synchronous rectifier winding and turns

NS4: Fourth synchronous rectifier winding and turns

Q1-Q3: Power switch

Q4-Q7: synchronous rectification switch

CO1-CO3: Energy storage capacitor

DO1: boost diode

D1~D4: diode

LM1: boost inductor

LR: Resonance inductor

LM2: Magnetizing inductance

CR: Resonance capacitor

V _IN : DC voltage

V _OUT : Output voltage

V _AC : Alternating current voltage

V _AA : Determination voltage

VF: reference voltage

VE: Error voltage

VO1-VO3: Pulsating DC voltage

GND1, GND2: ground potential

GD1-GD7: control signal

CM1: Fully open signal

CM2: Synchronous complementary signal

P1-P14: Foot position

Figure 1 is a functional block diagram of a power supply with synchronous rectification control and high resonance efficiency in an embodiment of the present invention.

Figure 2 is a schematic diagram of the implementation of the power supply in the embodiment of the present invention.

Figure 3 is a diagram of related signals when the power converter is operating in an embodiment of the present invention.

FIG. 1 is a functional block diagram of a power supply 100 with synchronous rectification control and high resonance efficiency in an embodiment of the present invention. The power supply 100 includes a boost type active power factor correction circuit 10, a resonant conversion circuit 20, a voltage detection circuit 30, and a control circuit 40. The boost type active power factor correction circuit 10 can receive an AC voltage V _AC supplied by a mains supply and convert the AC voltage V _AC into a pulsed DC voltage VO1. The resonant conversion circuit 20 can convert the pulsed DC voltage VO1 into an output voltage V _OUT to supply power to a load device (not shown in FIG. 1 ). The voltage detection circuit 30 can detect the state of the output voltage V _OUT to provide a corresponding detection voltage V _AA . The control circuit 40 can control the operation of the boost active power factor correction circuit 10 and the resonant conversion circuit 20 according to the detection voltage V _AA to perform voltage conversion and voltage regulation feedback compensation to achieve synchronous rectification control with high resonant efficiency.

FIG. 2 is a schematic diagram of the implementation of the power supply 100 in the embodiment of the present invention. In the embodiment shown in FIG. 2, the boost type active power factor correction circuit 10 includes a rectifier 12, a power switch Q1, a boost diode DO1, an energy storage capacitor CO1, and a boost inductor LM1, which can convert the AC voltage V _AC supplied by the mains into a pulsed DC voltage VO1. In the embodiment of the present invention, the rectifier 12 can be a bridge rectifier, which includes rectifier diodes D1-D4, and is used to convert the AC voltage V _AC supplied by the mains into a DC voltage V _IN . However, the implementation of the rectifier 12 does not limit the scope of the present invention.

The first end of the boost inductor LM1 is coupled to the rectifier 12 to receive the DC voltage V _IN , and the second end is selectively coupled to the ground potential GND1 through the power switch Q1 to store the energy of the DC voltage V _IN . The first end of the energy storage capacitor CO1 is coupled to the pulse DC voltage VO1 , and the second end is coupled to the ground potential GND1 to store the energy of the pulse DC voltage VO1 . The anode of the boost diode DO1 is coupled to the second end of the boost inductor LM1 , and the cathode is coupled to the first end of the energy storage capacitor CO1 . The first end of the power switch Q1 is coupled between the second end of the boost inductor LM1 and the anode of the boost diode DO1, and the second end is coupled to the ground potential GND1. The control end receives a control signal GD1, and can perform high-frequency switching according to the control signal GD1 to allow the boost inductor LM1 to store and release energy, so that the input current tracks the input voltage, thereby improving the power factor and reducing current harmonics.

In the boost type active power factor correction circuit 10, the boost inductor LM1, the boost diode DO1, the energy storage capacitor CO1 and the power switch Q1 can achieve the purpose of boosting. When the power switch Q1 is turned on during the period when the AC voltage V _AC is supplied by the mains, the second end of the boost inductor LM1 is coupled to the ground potential GND1. At this time, the boost inductor LM1 will generate an induced voltage in response to the change of the DC voltage V _IN , and then convert the electrical energy into magnetic energy for storage. When the power switch Q1 is turned off, the ground loop of the boost inductor LM1 is disconnected, and the magnetic energy stored in it is converted into electrical energy, allowing a large current to pass through the boost diode DO1 to charge the energy storage capacitor CO1. After multiple rapid switching of the power switch Q1, the DC voltage V _IN can be increased to provide the pulse DC voltage VO1.

In the embodiment shown in FIG. 2 , the resonant converter circuit 20 includes a transformer TR, power switches Q2-Q3, synchronous rectifier switches Q4-Q7, a resonant inductor LR, a magnetizing inductor LM2, a resonant capacitor CR, and energy storage capacitors CO2-CO3. The resonant converter circuit 20 can receive a pulsed DC voltage VO1 at its input terminal and provide an output voltage V _OUT at its output terminal. The transformer TR includes a primary winding (represented by turns NP) and four synchronous rectifier windings (represented by turns NS1-NS4, respectively), wherein the primary winding NP is disposed on the primary side of the transformer TR, and the synchronous rectifier windings NS1-NS4 are disposed on the secondary side of the transformer TR. The non-striking end of the synchronous rectifier winding NS1, the striking end of the synchronous rectifier winding NS2, the non-striking end of the synchronous rectifier winding NS3 and the striking end of the synchronous rectifier winding NS4 are coupled to a ground potential GND2. The synchronous rectifier winding NS1 is connected in series to the synchronous rectifier winding NS2, and the synchronous rectifier winding NS3 is connected in series to the synchronous rectifier winding NS4.

The first end of the power switch Q2 is coupled to the cathode of the boost inductor LM1 in the boost type active power factor correction circuit 10 to receive the pulsed DC voltage VO1, the second end is coupled to the power switch Q3, and the control end receives a control signal GD2. The first end of the power switch Q3 is coupled to the second end of the power switch Q1, the second end is coupled to the ground potential GND1, and the control end receives a control signal GD3. The first end of the synchronous rectification switch Q4 is coupled to the dot terminal of the synchronous rectification winding NS1 in the transformer TR, the second end is coupled to the output end of the power supply 100, and the control end receives a control signal GD4. The first end of the synchronous rectification switch Q5 is coupled to the non-pointing end of the synchronous rectification winding NS2 in the transformer TR, the second end is coupled to the output end of the power supply 100, and the control end receives a control signal GD5. The first end of the synchronous rectification switch Q6 is coupled to the pointing end of the synchronous rectification winding NS3 in the transformer TR, the second end is coupled to the output end of the power supply 100, and the control end receives a control signal GD6. The first end of the synchronous rectification switch Q7 is coupled to the non-pointing end of the synchronous rectification winding NS4 in the transformer TR, the second end is coupled to the output end of the power supply 100, and the control end receives a control signal GD7.

The resonant inductor LR, the magnetizing inductor LM2 and the resonant capacitor CR form an LCC resonant circuit, which enables the power switches Q2 and Q3 to achieve a flexible switching of zero voltage or zero current, thereby solving the problem caused by high-frequency switching. The first end of the resonant inductor LR is coupled to the tapping end of the primary winding NP in the transformer TR, and the second end thereof is coupled between the second end of the power switch Q2 and the first end of the power switch Q3. The first end of the magnetizing inductor LM2 is coupled to the tapping end of the primary winding NP in the transformer TR, and the second end is coupled to the non-tapping end of the primary winding NP in the transformer TR. The first end of the resonant capacitor CR is coupled to the non-pointing end of the primary winding NP1 in the transformer TR, and the second end thereof is coupled to the ground potential GND1. The first end of the energy storage capacitor CO2 is coupled to the output end of the power supply 100, and the second end thereof is coupled to the ground potential GND2. The first end of the energy storage capacitor CO3 is coupled to the output end of the power supply 100, and the second end thereof is coupled to the ground potential GND2.

The pulsed DC voltage VO1 output by the boost active power factor correction circuit 10 is the input voltage of the resonant conversion circuit 20. The power switches Q2 and Q3 can perform high-frequency complementary switching according to the control signals GD2 and GD3 respectively, thereby making the resonant inductor LR, the excitation inductor LM2 and the resonant capacitor CR resonate with each other to achieve a flexible switching of zero voltage or zero current to reduce the switching loss. The transformer TR can sense the energy of the corresponding pulsed DC voltage VO1 stored in the primary side winding NP to the synchronous rectification winding NS1-NS4 to provide a pulsed DC voltage VO2 and/or a pulsed DC voltage VO3, thereby supplying the output voltage V _OUT .

The synchronous rectification switches Q4-Q7 can realize the synchronous rectification function at the secondary side of the transformer: when the synchronous rectification switch Q4 is turned on, the energy of the synchronous rectification winding NS1 can be transmitted to the output end of the power supply 100 to provide the pulsed DC voltage VO2; when the synchronous rectification switch Q5 is turned on, the energy of the synchronous rectification winding NS2 can be transmitted to the output end of the power supply 100 to provide the pulsed DC voltage VO2; when the synchronous rectification switch Q6 is turned on, the energy of the synchronous rectification winding NS3 can be transmitted to the output end of the power supply 100 to provide the pulsed DC voltage VO3; when the synchronous rectification switch Q7 is turned on, the energy of the synchronous rectification winding NS4 can be transmitted to the output end of the power supply 100 to provide the pulsed DC voltage VO3. The energy storage capacitor CO2 can store the energy (pulsating DC voltage VO2) of the synchronous rectifier winding NS1 or NS2 to supply the output voltage V _OUT , and the energy storage capacitor CO3 can store the energy (pulsating DC voltage VO3) of the synchronous rectifier winding NS3 or NS4 to supply the output voltage V _OUT . When the synchronous rectifier switches Q4-Q7 are all turned off, the power transmission path of the power supply 100 will be cut off, and at this time, the output terminal of the power supply 100 has no output (V _OUT =0V).

In the embodiment shown in FIG. 2 , the voltage detection circuit 30 includes an error amplifier 32 and a logic unit 34, which can provide a determination voltage V _AA according to the state of the output voltage V _OUT . The positive input terminal of the error amplifier 32 is coupled to a reference voltage VF, the negative input terminal thereof is coupled to the output terminal of the power supply 100 to receive the output voltage V _OUT , and the output terminal thereof is used to output an error voltage VE. The first input terminal of the logic unit 34 is coupled to the output terminal of the error amplifier 32 to receive the error voltage VE, the second input terminal thereof is coupled to the reference voltage VF, and the output terminal thereof is used to output the determination voltage V _AA . In one embodiment, when the error amplifier 32 determines that the voltage difference between its positive input terminal and negative input terminal is 0, it will output an error voltage VE with a first potential (e.g., a high potential); when it determines that the voltage difference between its positive input terminal and negative input terminal is not 0, it will output an error voltage VE with a second potential (e.g., a low potential). When the logic unit 34 determines that the first input terminal (error voltage VE) and the second input terminal (reference voltage VF) are both high, it will output a determination voltage V _AA having a third potential (e.g., high potential); when it determines that the first input terminal (error voltage VE) and the second input terminal (reference voltage VF) are not both high, it will output a determination voltage V _AA having a fourth potential (e.g., low potential). In one embodiment, the logic unit 34 of the voltage detection circuit 30 may be an AND gate, but is not limited thereto.

In the embodiment shown in FIG. 2 , the control circuit 40 includes pulse width modulation integrated circuits PWMIC1-PWMIC2 and synchronous rectifier switch control integrated circuits SRIC1-SRIC2. The pulse width modulation integrated circuit PWMIC1 includes pins P1, P8 and P9, wherein the pin P1 is used to output a control signal GD1 switching between a first enable potential and a first disable potential at a high frequency to the control terminal of the power switch Q1, the pin P8 is coupled to the voltage detection circuit 30 to receive the determination voltage V _AA , and the pin P9 is used to selectively output a full-on signal CM1 or a synchronous complementary signal CM2 to the synchronous rectifier switch control integrated circuits SRIC1 and SRIC2. The pulse width modulation integrated circuit PWMIC2 includes pins P2, P3 and P14, wherein the pin P2 is used to output a control signal GD2 for high-frequency switching between a second enable potential and a second disable potential to the control end of the power switch Q2, the pin P3 is used to output a control signal GD3 for high-frequency switching between a third enable potential and a third disable potential to the control end of the power switch Q3, and the pin P14 is used to output a reference voltage VF to the voltage detection circuit 30.

The synchronous rectifier switch control integrated circuit SRIC1 includes pins P4, P5, P10 and P12, wherein pin P4 is used to selectively output a control signal GD4 having a fourth enable potential or a fourth disable potential to the control end of the synchronous rectifier switch Q4, pin P5 is used to selectively output a control signal GD5 having a fifth enable potential or a fifth disable potential to the control end of the synchronous rectifier switch Q5, pin P10 is coupled to pin P9 of the pulse width modulation integrated circuit PWMIC1 to receive the full-on signal CM1 or the synchronous complementary signal CM2, and pin P12 is coupled to the synchronous rectifier switch control integrated circuit SRIC2.

The synchronous rectifier switch control integrated circuit SRIC2 includes pins P6, P7, P11 and P13, wherein pin P6 is used to selectively output a control signal GD6 having a sixth enable potential or a sixth disable potential to the control end of the synchronous rectifier switch Q6, pin P7 is used to selectively output a control signal GD7 having a seventh enable potential or a seventh disable potential to the control end of the synchronous rectifier switch Q7, pin P11 is coupled to pin P9 of the pulse width modulation integrated circuit PWMIC1 to receive the full-on signal CM1 or the synchronous complementary signal CM2, and pin P13 is coupled to pin P12 of the synchronous rectifier switch control integrated circuit SRIC1.

FIG3 is a diagram of related signals when the power converter 100 is operating in the embodiment of the present invention. As shown in FIG2 and FIG3, when the power supply 100 is not connected to the mains during the time point T0-T1, all control signals are 0, and the power supply 100 has no output (V _OUT =0).

As shown in FIG. 2 and FIG. 3 , after time point T1, the power supply 100 is connected to the mains, and the rectifier 12 of the boost active power factor correction circuit 10 can convert the AC voltage V _AC into the DC voltage V _IN , and the pulse width modulation integrated circuit PWMIC1 outputs a control signal GD1 that switches between the first enable potential and the first disable potential at a high frequency to the control end of the power switch Q1 through the pin P1, so that the power switch Q1 can switch between the on and off states at a high frequency accordingly, thereby allowing the boost inductor LM1 to periodically store and release energy, so as to provide a boosted pulsed DC voltage VO1 on the primary side of the transformer TR. Next, the pulse DC voltage VO1 outputted after the boost active power factor correction circuit 10 operates stably is the input voltage of the resonant conversion circuit 20, and the pulse width modulation integrated circuit PWMIC2 outputs a control signal GD2 for high-frequency switching between the second enable potential and the second disable potential to the control end of the power switch Q2 through the pin P2, and outputs a control signal GD3 for high-frequency switching between the third enable potential and the third disable potential to the control end of the power switch Q3 through the pin P3. The control signals GD2 and GD3 are complementary signals, that is, when the control signal GD2 has the second enable potential, the control signal GD3 will have the third disable potential, and when the control signal GD2 has the second disable potential, the control signal GD3 will have the third enable potential, so that the power switches Q2 and Q3 can perform high-frequency complementary switching according to the control signals GD2 and GD3 respectively, thereby making the resonant inductor LR, the excitation inductor LM2 and the resonant capacitor CR resonate with each other to achieve a flexible switching of zero voltage or zero current to reduce the switching loss. In this case, the transformer TR can sense the energy of the corresponding pulse DC voltage VO1 stored in the primary side winding NP to the synchronous rectification winding NS1-NS4.

Between time points T1 and T2, the value of the output voltage V _OUT has not yet reached the level of the reference voltage VF, and the error amplifier 32 will output the error voltage VE with a second potential (e.g., a low potential). When the logic unit 34 determines that its first input terminal (low potential error voltage VE) and the second input terminal (high potential reference voltage VF) are not both high potentials, it will output the determination voltage V _AA with a fourth potential (e.g., a low potential). After receiving the determination voltage V _AA having a fourth potential (eg, a low potential), the pulse width modulation integrated circuit PWMIC1 outputs a full-on signal CM1 through the pin P9 to the pin P10 of the synchronous rectifier switch control integrated circuit SRIC1 and the pin P11 of the synchronous rectifier switch control integrated circuit SRIC2.

The full-on signal CM1 corresponds to the full-on synchronous rectification operation, that is, the pulse width modulation integrated circuit PWMIC1 will instruct the synchronous rectification switch control integrated circuit SRIC1 to output the control signal GD4 with the fourth enable potential through its pin P4 to turn on the synchronous rectification switch Q4, and instruct the synchronous rectification switch control integrated circuit SRIC1 to output the fifth enable potential through its pin P5. The control signal GD5 is used to turn on the synchronous rectifier switch Q5, and the synchronous rectifier switch control integrated circuit SRIC2 is instructed to output the control signal GD6 with the sixth enable potential through its pin P6 to turn on the synchronous rectifier switch Q6, and the synchronous rectifier switch control integrated circuit SRIC2 is instructed to output the control signal GD7 with the seventh enable potential through its pin P7 to turn on the synchronous rectifier switch Q7. When the synchronous rectifier switches Q4-Q7 are all turned on, the energy stored in the synchronous rectifier windings NS1-NS4 can be transmitted to the output end of the power supply 100 to provide the pulsed DC voltage VO2 and the pulsed DC voltage VO3, so that the value of the output voltage V _OUT continues to rise.

As shown in FIG. 2 and FIG. 3 , at time point T2, the value of the output voltage V _OUT reaches the level of the reference voltage VF, that is, the voltage difference between the positive input terminal and the negative input terminal of the error amplifier 32 is 0, and the error amplifier 32 outputs the error voltage VE with a first potential (e.g., a high potential). When the logic unit 34 determines that its first input terminal (high potential error voltage VE) and the second input terminal (high potential reference voltage VF) are both high, it outputs the determination voltage V _AA with a third potential (e.g., a high potential). After receiving the determination voltage V _AA having a third potential (eg, a high potential), the pulse width modulation integrated circuit PWMIC1 outputs a synchronous complementary signal CM2 through the pin P9 to the pin P10 of the synchronous rectifier switch control integrated circuit SRIC1 and the pin P11 of the synchronous rectifier switch control integrated circuit SRIC2.

The synchronous complementary signal CM2 corresponds to the complementary synchronous rectification operation, that is, the pulse width modulation integrated circuit PWMIC1 will instruct the synchronous rectification switch control integrated circuit SRIC1 to output the control signal GD4 with the fourth disable potential through its pin P4 in the odd cycle after the time point T2 to turn off the synchronous rectification switch Q4, instructing the synchronous rectification switch control integrated circuit SRIC1. The control signal GD5 having the fifth enable potential is outputted through its pin P5 to turn on the synchronous rectifier switch Q5, the synchronous rectifier switch control integrated circuit SRIC2 is instructed to output the control signal GD6 having the sixth disable potential through its pin P6 to turn off the synchronous rectifier switch Q6, and the synchronous rectifier switch control integrated circuit SRIC2 is instructed to output the control signal GD7 having the seventh enable potential through its pin P7 to turn on the synchronous rectifier switch Q7. When the synchronous rectifier switches Q4 and Q6 are turned off and the synchronous rectifier switches Q5 and Q7 are turned on, the energy stored in the synchronous rectifier windings NS2 and NS4 can be transmitted to the output end of the power supply 100 to provide the pulse DC voltage VO2 and the pulse DC voltage VO3, so that the value of the output voltage V _OUT remains stable.

Similarly, the pulse width modulation integrated circuit PWMIC1 will instruct the synchronous rectification switch control integrated circuit SRIC1 to output the control signal GD4 with the fourth enable potential through its pin P4 to turn on the synchronous rectification switch Q4 in the even cycle after the time point T2 (for example, the time point T3-T4, T5-T6), and instruct the synchronous rectification switch control integrated circuit SRIC1 to output the control signal GD4 with the fifth enable potential through its pin P5 to turn on the synchronous rectification switch Q4. The control signal GD5 with the disable potential turns off the synchronous rectifier switch Q5, instructs the synchronous rectifier switch control integrated circuit SRIC2 to output the control signal GD6 with the sixth enable potential through its pin P6 to turn on the synchronous rectifier switch Q6, and instructs the synchronous rectifier switch control integrated circuit SRIC2 to output the control signal GD7 with the seventh disable potential through its pin P7 to turn off the synchronous rectifier switch Q7. When the synchronous rectifier switches Q4 and Q6 are turned on and the synchronous rectifier switches Q5 and Q7 are turned off, the energy stored in the synchronous rectifier windings NS1 and NS3 can be transmitted to the output terminal of the power supply 100 to provide the pulsed DC voltage VO2 and the pulsed DC voltage VO3, so that the value of the output voltage V _OUT remains stable.

In the embodiment of the present invention, when the pin P10 of the synchronous rectifier switch control integrated circuit SRIC1 and the pin P11 of the synchronous rectifier switch control integrated circuit SRIC2 receive the synchronous complementary signal CM2, the synchronous rectifier switch control integrated circuit SRIC1 can communicate through the pin P12 and the pin P13 of the synchronous rectifier switch control integrated circuit SRIC2 to ensure that the control signal GD4 and the control signal GD6 have the same phase and the opposite phase to the control signal GD7, and ensure that the control signal GD5 and the control signal GD7 have the same phase and the opposite phase to the control signal GD6.

In the embodiment of the present invention, the power switches Q1-Q3 and the synchronous rectification switches Q4-Q7 can be metal-oxide-semiconductor field-effect transistors (MOSFET), bipolar junction transistors (BJT), or other components with similar functions. For N-type transistors, the enable potential is high and the disable potential is low; for P-type transistors, the enable potential is low and the disable potential is high. However, the types of the above switches do not limit the scope of the present invention.

In summary, in the power supply 100 of the present invention, the boost active power factor correction circuit 10 can improve the power factor of the AC power supply end, and the resonant converter circuit 20 can convert the output voltage of the boost active power factor correction circuit 10 into the output voltage V _OUT required for the operation of the load device. The voltage detection circuit 30 can detect the state of the output voltage V _OUT , so that the control circuit 40 can instruct the resonant converter circuit 20 to perform a full-open synchronous rectification operation when the value of the output voltage V _OUT has not yet reached the reference voltage, and instruct the resonant converter circuit 20 to perform a complementary synchronous rectification operation when the value of the output voltage V _OUT reaches the reference voltage, thereby providing synchronous rectification control with high resonance efficiency.

The above is only the preferred embodiment of the present invention. All equivalent changes and modifications made according to the scope of the patent application of the present invention shall fall within the scope of the present invention.

10: Boost type active power factor correction circuit

20: Resonance conversion circuit

30: Voltage detection circuit

40: Control circuit

100: Power supply

V _OUT : Output voltage

V _AC : Alternating current voltage

V _AA : Determination voltage

VO1: Pulsating DC voltage

GD1-GD7: control signal

P1-P8: Foot position

Claims (10)

A power supply with synchronous rectification control and high resonance efficiency, comprising: an input terminal for receiving an AC voltage supplied by a mains; an output terminal for outputting an output voltage; a boost type active power factor correction circuit, comprising a first switch for converting the AC voltage into a DC voltage, and then converting the DC voltage into a first pulsed DC voltage; a resonance conversion circuit for converting the first pulsed DC voltage into the output voltage, comprising: a transformer for The first pulsed DC voltage is induced from a primary side to a secondary side to supply the output voltage, which includes: a first synchronous rectification winding, arranged on the secondary side, including a first dotted end and a first non-dotted end; a second synchronous rectification winding, arranged on the secondary side and connected in series with the first synchronous rectification winding, including a second dotted end and a second non-dotted end; a third synchronous rectification winding, arranged on the secondary side, including a third dotted end and a third non-dotted end; a fourth synchronous rectification winding A current winding, arranged on the secondary side and connected in series with the third synchronous rectifier winding, comprising a fourth dotted end and a fourth non-dotted end; and a primary side winding, arranged on the primary side, comprising a fifth dotted end and a fifth non-dotted end; a resonant circuit, arranged on the primary side; a second switch and a third switch, arranged on the primary side, for controlling the operation of the resonant circuit; a fourth switch, arranged on the secondary side, for selectively transferring the energy stored in the first synchronous rectifier winding to the first synchronous rectifier winding; to the output terminal to provide a second pulsed DC voltage; a fifth switch, arranged on the secondary side, for selectively transmitting the energy stored in the second synchronous rectifier winding to the output terminal to provide the second pulsed DC voltage; a sixth switch, arranged on the secondary side, for selectively transmitting the energy stored in the third synchronous rectifier winding to the output terminal to provide a third pulsed DC voltage; and a seventh switch, arranged on the secondary side, for selectively transmitting the energy stored in the fourth synchronous rectifier winding to the output terminal to provide a third pulsed DC voltage. The invention relates to a circuit for transmitting the output voltage to the output terminal to provide the third pulsed DC voltage; a voltage detection circuit for detecting the state of the output voltage and outputting a corresponding judgment voltage; and a control circuit for: outputting a first control signal that is periodically switched between a first enabling potential and a first disabling potential to control the operation of the first switch; outputting a second control signal that is periodically switched between a second enabling potential and a second disabling potential to control the operation of the second switch; and outputting a first control signal that is periodically switched between a first enabling potential and a second disabling potential to control the operation of the second switch. A third control signal that periodically switches between three enabling potentials and a third disabling potential to control the operation of the third switch, wherein the second control signal and the third control signal are complementary signals; When the output voltage is determined to be less than a reference voltage according to the determination voltage, a fourth control signal with a fourth enabling potential is output to turn on the fourth switch, a fifth control signal with a fifth enabling potential is output to turn on the fifth switch, and a sixth control signal with a sixth enabling potential is output to turn on the fifth switch. The output voltage is determined to be not less than the reference voltage at a specific time point according to the determination voltage, and the fourth control signal with a fourth disable potential is output within a first cycle after the specific time point to turn off the fourth switch, the fifth control signal with the fifth enable potential is output to turn on the fifth switch, and the sixth control signal with a sixth disable potential is output to turn off the fourth switch. The sixth switch is turned off, and the seventh control signal with the seventh enable potential is output to turn on the seventh switch; and in a second cycle following the first cycle, the fourth control signal with the fourth enable potential is output to turn on the fourth switch, the fifth control signal with a fifth disable potential is output to turn off the fifth switch, the sixth control signal with the sixth enable potential is output to turn on the sixth switch, and the seventh control signal with a seventh disable potential is output to turn on the seventh switch. The power supply as claimed in claim 1, wherein: the boost type active power factor correction circuit further comprises: a rectifier for converting the AC voltage into the DC voltage; a boost inductor comprising: a first end coupled to the rectifier to receive the DC voltage; and a second end; a boost diode comprising: an anode coupled to the second end of the boost inductor; and a cathode coupled to the first pulsed DC voltage; and a The first energy storage capacitor is used to store the energy of the first pulsed DC voltage, and includes: a first end coupled to the first pulsed DC voltage; and a second end coupled to a first ground potential; and the first switch includes: a first end coupled between the second end of the boost inductor and the anode of the boost diode; a second end coupled to the first ground potential; and a control end coupled to the control circuit to receive the first control signal. A power supply as described in claim 1, wherein: the resonant circuit comprises: a magnetizing inductor, comprising: a first end coupled to the fifth dotted end of the primary side winding; and a second end coupled to the fifth non-dotted end of the primary side winding; a resonant inductor, comprising: a first end coupled to the fifth dotted end of the primary side winding; and a second end; and a resonant capacitor, comprising: a first end coupled to the fifth non-dotted end of the primary side winding; and A second terminal coupled to a first ground potential; the second switch comprises: a first terminal coupled to the first pulsed DC voltage; a second terminal coupled to the second terminal of the resonant inductor; and a control terminal coupled to the control circuit to receive the second control signal; and the third switch comprises: a first terminal coupled to the second terminal of the resonant inductor; a second terminal coupled to the first ground potential; and a control terminal coupled to the control circuit to receive the third control signal. A power supply as described in claim 1, wherein: the resonant conversion circuit further includes: a second energy storage capacitor for storing energy of the second pulsed DC voltage to supply the output voltage, which includes: a first end coupled to the output end; and a second end coupled to a second ground potential; and a third energy storage capacitor for storing energy of the third pulsed DC voltage to supply the output voltage, which includes: a first end coupled to the output end; and a second end coupled to the second ground potential; the fourth switch includes: a first end coupled to the first dotting end of the first synchronous rectification winding; a second end coupled to the first end of the second energy storage capacitor; and a control end coupled to the control circuit to receive the fourth control signal ; The fifth switch includes: a first end coupled to the second non-point-point end of the second synchronous rectifier winding; a second end coupled to the first end of the second energy storage capacitor; and a control end coupled to the control circuit to receive the fifth control signal; the sixth switch includes: a first end coupled to the third point-point end of the third synchronous rectifier winding; a second end coupled to the first end of the third energy storage capacitor; and a control end coupled to the control circuit to receive the sixth control signal; and the seventh switch includes: a first end coupled to the fourth non-point-point end of the fourth synchronous rectifier winding; a second end coupled to the first end of the third energy storage capacitor; and a control end coupled to the control circuit to receive the seventh control signal. A power supply as described in claim 1, wherein the voltage detection circuit comprises: an error amplifier, which comprises: a positive input terminal coupled to the reference voltage; a negative input terminal coupled to the output terminal to receive the output voltage; and an output terminal for outputting an error voltage according to the voltage difference between the positive input terminal and the negative input terminal; and a logic unit, which comprises: a first input terminal coupled to the output terminal of the error amplifier to receive the error voltage; a second input terminal coupled to the reference voltage; and an output terminal for outputting the judgment voltage according to the potentials of the first input terminal and the second input terminal. A power supply as described in claim 1, wherein the control circuit comprises: a first pin, a second pin, a third pin, a fourth pin, a fifth pin, a sixth pin, a seventh pin, an eighth pin, a ninth pin, a tenth pin, an eleventh pin, a twelfth pin, a thirteenth pin, and a fourteenth pin; a first pulse width modulation integrated circuit, used to: output the first control signal through the first pin; receive the judgment voltage through the eighth pin; and selectively output a full-on signal or a synchronous complementary signal through the ninth pin; a second pulse width modulation integrated circuit, used to: output the first control signal through the first pin; receive the judgment voltage through the eighth pin; and selectively output a full-on signal or a synchronous complementary signal through the ninth pin; output the second control signal through the second pin; output the third control signal through the third pin; and output the reference voltage through the fourteenth pin; a first synchronous rectifier switch control integrated circuit, used to: output the fourth control signal through the fourth pin; output the fifth control signal through the fifth pin; and receive the full-on signal or the synchronous complementary signal through the tenth pin; and a second synchronous rectifier switch control integrated circuit, used to: output the sixth control signal through the sixth pin; output the seventh control signal through the seventh pin; and receive the full-on signal or the synchronous complementary signal through the eleventh pin. The power supply as claimed in claim 6, wherein: when it is determined that the value of the output voltage is less than the reference voltage, the voltage detection circuit outputs the determination voltage with a first potential; when it is determined that the value of the output voltage is not less than the reference voltage, the voltage detection circuit outputs the determination voltage with a second potential; when the first pulse width is When the first pulse width modulation integrated circuit receives the judgment voltage with the first potential through the eighth pin, it is used to output the full-on signal through the ninth pin; and when the first pulse width modulation integrated circuit receives the judgment voltage with the second potential through the eighth pin, it is used to output the synchronous complementary signal through the ninth pin. The power supply as described in claim 7, wherein: when the first synchronous rectifier switch control integrated circuit receives the fully-on signal through the tenth pin, it is further used to output the fourth control signal with the fourth enable potential through the fourth pin and the fifth control signal with the fifth enable potential through the fifth pin; when the second synchronous rectifier switch control integrated circuit receives the fully-on signal through the eleventh pin, it is further used to output the sixth control signal with the sixth enable potential through the sixth pin and the seventh enable potential through the seventh pin. When the first synchronous rectifier switch control integrated circuit receives the synchronous complementary signal through the tenth pin, the fourth control signal output through the fourth pin and the fifth control signal output through the fifth pin have opposite phases; and when the second synchronous rectifier switch control integrated circuit receives the synchronous complementary signal through the eleventh pin, the sixth control signal output through the sixth pin and the seventh control signal output through the seventh pin have opposite phases and have the same phase as the fourth control signal. A power supply as described in claim 6, wherein when the first synchronous rectifier switch control integrated circuit receives the synchronous complementary signal through the tenth pin, it is used to communicate with the second synchronous rectifier switch control integrated circuit through the twelfth pin to ensure that the fourth control signal has the same phase as the sixth control signal and has an opposite phase to the seventh control signal. A power supply as described in claim 9, wherein when the second synchronous rectifier switch control integrated circuit receives the synchronous complementary signal through the eleventh pin, it is used to communicate with the first synchronous rectifier switch control integrated circuit through the thirteenth pin to ensure that the sixth control signal has the same phase as the fourth control signal and has an opposite phase to the fifth control signal.

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