TWI891489B - Power supply device with high output stability - Google Patents

Abstract

A power supply device with high output stability includes a bridge rectifier, a boost inductor, a sense resistor, a power switch element, a first output stage circuit, a switch circuit, a tunable inductive element, a transformer, a resonant capacitor, a tunable resistive element, a second output stage circuit, and a detection and control circuit. The detection and control circuit monitors a voltage difference across the sense resistor. The detection and control circuit also controls the tunable inductive element and the tunable resistive element according to the voltage difference.

Description

High output stability power supply

The present invention relates to a power supply, and more particularly to a power supply with high output stability.

Power supplies are essential components in laptop computers. However, if the power supply's output stability is insufficient, it can easily lead to a decline in the overall performance of the laptop. This necessitates a new solution to overcome the difficulties faced by previous technologies.

In a preferred embodiment, the present invention provides a power supply with high output stability, comprising: a bridge rectifier, generating a rectified potential according to a first input potential and a second input potential; a boost inductor, receiving the rectified potential; a sense resistor, coupled to the boost inductor; a power switch, selectively coupling the sense resistor to a ground potential according to a first drive potential; a first output stage circuit, coupled to the sense resistor, and generating an intermediate potential; a switching circuit, generating a switching potential according to the intermediate potential, a second drive potential, and a third drive potential; an adjustable inductor, controlled by a first control potential; a transformer, comprising a mains A transformer comprises a main coil, a first secondary coil, and a second secondary coil, wherein the transformer has a built-in excitation inductor, and the main coil receives the switching potential via the adjustable inductance element; a resonant capacitor is coupled to the excitation inductor; an adjustable resistance element is coupled to the excitation inductor and is controlled by a second control potential; a second output stage circuit is coupled to the first secondary coil and the second secondary coil and generates an output potential; and a detection and control circuit monitors a potential difference across the sense resistor and generates the first drive potential, the second drive potential, and the third drive potential; wherein the detection and control circuit further generates the first control potential and the second control potential according to the potential difference.

In some embodiments, the bridge rectifier includes: a first diode having an anode and a cathode, wherein the anode of the first diode is coupled to a first input node to receive the first input potential, and the cathode of the first diode is coupled to a first node to output the rectified potential; a second diode having an anode and a cathode, wherein the anode of the second diode is coupled to a second input node to receive the second input potential, and the cathode of the second diode is coupled to the first node; a third diode having an anode and a cathode, wherein the anode of the third diode is coupled to the ground potential, and the cathode of the third diode is coupled to the ground potential. The cathode of the body is coupled to the first input node; and a fourth diode having an anode and a cathode, wherein the anode of the fourth diode is coupled to the ground potential, and the cathode of the fourth diode is coupled to the second input node; wherein the boost inductor has a first end and a second end, the first end of the boost inductor is coupled to the first node to receive the rectified potential, and the second end of the boost inductor is coupled to a second node; wherein the sensing resistor has a first end and a second end, the first end of the sensing resistor is coupled to the second node, and the second end of the sensing resistor is coupled to a third node.

In some embodiments, the power switch includes: a first transistor having a control terminal, a first terminal, and a second terminal, wherein the control terminal of the first transistor is used to receive the first driving potential, the first terminal of the first transistor is coupled to the ground potential, and the second terminal of the first transistor is coupled to the third node.

In some embodiments, the first output stage circuit includes: a fifth diode having an anode and a cathode, wherein the anode of the fifth diode is coupled to the third node, and the cathode of the fifth diode is coupled to a fourth node to output the intermediate potential; and a first capacitor having a first end and a second end, wherein the first end of the first capacitor is coupled to the fourth node, and the second end of the first capacitor is coupled to the ground potential.

In some embodiments, the switching circuit includes: a second transistor having a control terminal, a first terminal, and a second terminal, wherein the control terminal of the second transistor is used to receive the second drive potential, the first terminal of the second transistor is coupled to a fifth node to output the switching potential, and the second terminal of the second transistor is coupled to the fourth node to receive the intermediate potential; and a third transistor having a control terminal, a first terminal, and a second terminal, wherein the control terminal of the third transistor is used to receive the third drive potential, the first terminal of the third transistor is coupled to the ground potential, and the second terminal of the third transistor is coupled to the fifth node.

In some embodiments, the adjustable inductor element includes: a resonant inductor having a first terminal and a second terminal, wherein the first terminal of the resonant inductor is coupled to the fifth node to receive the switching potential, and the second terminal of the resonant inductor is coupled to a sixth node; and a fourth transistor having a control terminal, a first terminal, and a second terminal, wherein the control terminal of the fourth transistor is used to receive the first control potential, the first terminal of the fourth transistor is coupled to the sixth node, and the second terminal of the fourth transistor is coupled to the fifth node.

In some embodiments, the main coil has a first end and a second end, the first end of the main coil is coupled to the sixth node, the second end of the main coil is coupled to a seventh node, the excitation inductor has a first end and a second end, the first end of the excitation inductor is coupled to the sixth node, the second end of the excitation inductor is coupled to the seventh node, the resonant capacitor has a first end and a second end, the first end of the resonant capacitor is coupled to the sixth node, and the second end of the resonant capacitor is coupled to the seventh node. is coupled to the seventh node, the second end of the resonant capacitor is coupled to the ground potential, the first secondary coil has a first end and a second end, the first end of the first secondary coil is coupled to an eighth node, the second end of the first secondary coil is coupled to a common node, the second secondary coil has a first end and a second end, the first end of the second secondary coil is coupled to the common node, and the second end of the second secondary coil is coupled to a ninth node.

In some embodiments, the adjustable resistance element includes: a resonant resistor having a first terminal and a second terminal, wherein the first terminal of the resonant resistor is coupled to a tenth node, and the second terminal of the resonant resistor is coupled to the ground potential; and a fifth transistor having a control terminal, a first terminal, and a second terminal, wherein the control terminal of the fifth transistor is used to receive the second control potential, the first terminal of the fifth transistor is coupled to the tenth node, and the second terminal of the fifth transistor is coupled to the seventh node.

In some embodiments, the second output stage circuit includes: a sixth diode having an anode and a cathode, wherein the anode of the sixth diode is coupled to the eighth node, and the cathode of the sixth diode is coupled to an output node to output the output potential; a seventh diode having an anode and a cathode, wherein the anode of the seventh diode is coupled to the ninth node, and the cathode of the seventh diode is coupled to the output node; and a second capacitor having a first end and a second end, wherein the first end of the second capacitor is coupled to the output node, and the second end of the second capacitor is coupled to the common node.

In some embodiments, the detection and control circuit includes: a microcontroller, generating a first critical potential, a second critical potential, the first driving potential, the second driving potential, and the third driving potential, wherein the first critical potential is higher than the second critical potential; a sensing circuit, obtaining the potential difference across the sensing resistor to generate a sensing potential; an averaging circuit, calculating an average value of the sensing potential to generate an average potential; a first comparator, having a positive input terminal, a negative input terminal, and an output terminal, wherein the positive input terminal of the first comparator is used to receive the first critical potential, the negative input terminal of the first comparator is used to receive the average potential, and the first comparator is used to receive the average potential. The output terminal of the comparator is used to output a first comparison potential; a second comparator has a positive input terminal, a negative input terminal, and an output terminal, wherein the positive input terminal of the second comparator is used to receive the second threshold potential, the negative input terminal of the second comparator is used to receive the average potential, and the output terminal of the second comparator is used to output a first comparison potential. a first linear optical coupler comprising a first light emitting diode and a first bipolar junction transistor, wherein the first light emitting diode has an anode and a cathode, the anode of the first light emitting diode is used to receive the first reference potential, the cathode of the first light emitting diode is coupled to the ground potential, and the first bipolar junction transistor The first bipolar junction transistor has a collector and an emitter, the collector of the first bipolar junction transistor is coupled to a first internal node to output a first feedback potential, and the emitter of the first bipolar junction transistor is coupled to a common node; a second linear optical coupler includes a second light-emitting diode and a second bipolar junction transistor, wherein the second light-emitting diode The second light-emitting diode has an anode and a cathode, the anode of the second light-emitting diode is used to receive the second comparison potential, the cathode of the second light-emitting diode is coupled to the ground potential, the second bipolar junction transistor has a collector and an emitter, the collector of the second bipolar junction transistor is coupled to a second internal node to output a second feedback potential, The emitter of the second bipolar junction transistor is coupled to the common node; a third capacitor has a first end and a second end, wherein the first end of the third capacitor is coupled to the first internal node, and the second end of the third capacitor is coupled to the common node; a fourth capacitor has a first end and a second end, wherein the first end of the fourth capacitor is coupled to the second internal node, and the second end of the fourth capacitor is coupled to the common node; a first amplifier amplifies the first feedback potential by a first gain factor to generate the first control potential; and a second amplifier amplifies the second feedback potential by a second gain factor to generate the second control potential.

In order to make the purpose, features and advantages of the present invention more clearly understood, specific embodiments of the present invention are given below and described in detail with reference to the accompanying drawings.

Certain terms are used in the specification and patent application to refer to specific components. Those skilled in the art will understand that hardware manufacturers may use different terms to refer to the same component. This specification and patent application do not use differences in name as a way to distinguish components, but rather use differences in the functions of the components as the criterion for distinction. The words "include" and "including" mentioned throughout the specification and patent application are open-ended terms and should be interpreted as "including but not limited to". The word "substantially" means that within an acceptable error range, those skilled in the art can solve the technical problem within a certain error range and achieve the basic technical effect. In addition, the word "coupled" in this specification includes any direct and indirect electrical connection means. Therefore, if a first device is described herein as being coupled to a second device, it means that the first device may be directly electrically connected to the second device, or indirectly electrically connected to the second device via other devices or connection means.

FIG1 is a schematic diagram of a power supply 100 according to an embodiment of the present invention. For example, power supply 100 can be used in a desktop computer, a laptop computer, or an all-in-one computer. As shown in FIG1 , power supply 100 includes a bridge rectifier 110, a boost inductor LU, a sense resistor RS, a power switch 120, a first output stage circuit 130, a switching circuit 140, an adjustable inductor 150, a transformer 160, a resonant capacitor CR, an adjustable resistance 170, a second output stage circuit 180, and a detection and control circuit 190. It should be noted that, although not shown in FIG. 1 , the power supply 100 may further include other components, such as a voltage regulator and/or a negative feedback circuit.

The bridge rectifier 110 can generate a rectified potential VR based on a first input potential VIN1 and a second input potential VIN2, wherein an AC voltage having any frequency and any amplitude can be formed between the first input potential VIN1 and the second input potential VIN2. For example, the frequency of the AC voltage can be approximately 50 Hz or 60 Hz, and the RMS value of the AC voltage can be approximately between 90 V and 264 V, but is not limited thereto. The boost inductor LU can receive the rectified potential VR. The sense resistor RS is coupled to the boost inductor LU. The power switch 120 can selectively couple the sense resistor RS to a ground potential VSS (e.g., 0 V) based on a first drive potential VG1. For example, if the first drive potential VG1 has a high logic level (i.e., a logic "1"), the power switch 120 may couple the sense resistor RS to the ground potential VSS (i.e., the power switch 120 may be similar to a short circuit path). Conversely, if the first drive potential VG1 has a low logic level (i.e., a logic "0"), the power switch 120 will not couple the sense resistor RS to the ground potential VSS (i.e., the power switch 120 may be similar to an open circuit path). The first output stage circuit 130 is coupled to the sense resistor RS and may generate an intermediate potential VE. The switching circuit 140 can generate the switching potential VW according to the intermediate potential VE, a second driving potential VG2, and a third driving potential VG3.

The adjustable inductor element 150 is controlled by a first control potential VC1. For example, if the first control potential VC1 has a high logic level, the adjustable inductor element 150 will be able to approximate another short-circuit path; conversely, if the first control potential VC1 has a low logic level, the adjustable inductor element 150 will be able to provide an inductance value. The transformer 160 includes a main coil 161, a first secondary coil 162, and a second secondary coil 163. The transformer 160 can further have a built-in excitation inductor LM, wherein the excitation inductor LM and the main coil 161 can be located on the same side of the transformer 160, while the first secondary coil 162 and the second secondary coil 163 can be located on opposite sides of the transformer 160. The main coil 161 receives a switching potential VW via the adjustable inductor 150, while the first and second auxiliary coils 162 and 163 operate in response to the switching potential VW. The resonant capacitor CR is coupled to the magnetizing inductor LM. The adjustable resistor 170 is coupled to the magnetizing inductor LM and controlled by a second control potential VC2. For example, if the second control potential VC2 has a high logic level, the adjustable resistor 170 provides a resistance value. Conversely, if the second control potential VC2 has a low logic level, the adjustable resistor 170 can approximate another open-circuit path.

The second output stage circuit 180 is coupled to the first and second secondary coils 162 and 163 and generates an output potential VOUT. For example, the output potential VOUT can be a DC potential with a potential level between 18V and 22V, but is not limited thereto. The detection and control circuit 190 monitors a potential difference ΔV across the sense resistor RS and generates a first drive potential VG1, a second drive potential VG2, and a third drive potential VG3. Furthermore, the detection and control circuit 190 generates a first control potential VC1 and a second control potential VC2 based on this potential difference ΔV. In some embodiments, based on different combinations of first and second control potentials VC1 and VC2, a resonant tank in power supply 100 can operate in one of three modes: LLC mode, LC mode, or LCR mode. Based on actual measurement results, the power supply 100 of the present invention can significantly improve its output stability.

The following embodiments will introduce the detailed structure and operation of the power supply 100. It must be understood that these drawings and descriptions are only examples and are not intended to limit the scope of the present invention.

FIG2 shows a circuit diagram of a power supply 200 according to an embodiment of the present invention. In the embodiment of FIG2 , the power supply 200 has a first input node NIN1, a second input node NIN2, and an output node NOUT, and includes a bridge rectifier 210, a boost inductor LU, a sense resistor RS, a power switch 220, a first output stage circuit 230, a switching circuit 240, an adjustable inductor 250, a transformer 260, a resonant capacitor CR, an adjustable resistance 270, a second output stage circuit 280, and a detection and control circuit 290. The first input node NIN1 and the second input node NIN2 of the power supply 200 can respectively receive a first input potential VIN1 and a second input potential VIN2 from an external input power source (not shown), and the output node NOUT of the power supply 200 can be used to output an output potential VOUT to a system end, such as a laptop computer (not shown).

The bridge rectifier 210 includes a first diode D1, a second diode D2, a third diode D3, and a fourth diode D4. The first diode D1 has an anode and a cathode, wherein the anode of the first diode D1 is coupled to the first input node NIN1, and the cathode of the first diode D1 is coupled to the first node N1 to output a rectified potential VR. The second diode D2 has an anode and a cathode, wherein the anode of the second diode D2 is coupled to the second input node NIN2, and the cathode of the second diode D2 is coupled to the first node N1. The third diode D3 has an anode and a cathode, wherein the anode of the third diode D3 is coupled to a ground potential VSS, and the cathode of the third diode D3 is coupled to the first input node NIN1. The fourth diode D4 has an anode and a cathode, wherein the anode of the fourth diode D4 is coupled to the ground potential VSS, and the cathode of the fourth diode D4 is coupled to the second input node NIN2.

The boost inductor LU has a first terminal and a second terminal, wherein the first terminal of the boost inductor LU is coupled to the first node N1 to receive the rectified potential VR, and the second terminal of the boost inductor LU is coupled to a second node N2.

The sensing resistor RS has a first terminal and a second terminal. The first terminal of the sensing resistor RS is coupled to the second node N2, and the second terminal of the sensing resistor RS is coupled to a third node N3. Furthermore, an inductor current IL can flow through the sensing resistor RS, causing a potential difference ΔV to form across the sensing resistor RS. It should be noted that because the potential difference ΔV is proportional to the inductor current IL, the potential difference ΔV can also be used to indicate the instantaneous load status of the power supply 200.

The power switch 220 includes a first transistor M1. For example, the first transistor M1 can be an N-type Metal-Oxide-Semiconductor Field-Effect Transistor (NMOSFET). The first transistor M1 has a control terminal (e.g., a gate), a first terminal (e.g., a source), and a second terminal (e.g., a drain). The control terminal of the first transistor M1 is configured to receive a first drive potential VG1. The first terminal of the first transistor M1 is coupled to the ground potential VSS. The second terminal of the first transistor M1 is coupled to the third node N3.

The first output stage circuit 230 includes a fifth diode D5 and a first capacitor C1. The fifth diode D5 has an anode and a cathode. The anode of the fifth diode D5 is coupled to the third node N3, and the cathode of the fifth diode D5 is coupled to the fourth node N4 to output an intermediate potential VE. The first capacitor C1 has a first terminal and a second terminal. The first terminal of the first capacitor C1 is coupled to the fourth node N4, and the second terminal of the first capacitor C1 is coupled to the ground potential VSS.

The switching circuit 240 includes a second transistor M2 and a third transistor M3. For example, the second transistor M2 and the third transistor M3 can each be an N-type metal oxide semiconductor field effect transistor. The second transistor M2 has a control terminal (e.g., a gate), a first terminal (e.g., a source), and a second terminal (e.g., a drain). The control terminal of the second transistor M2 is configured to receive a second drive potential VG2. The first terminal of the second transistor M2 is coupled to a fifth node N5 to output a switching potential VW. The second terminal of the second transistor M2 is coupled to a fourth node N4 to receive an intermediate potential VE. The third transistor M3 has a control terminal (e.g., a gate), a first terminal (e.g., a source), and a second terminal (e.g., a drain). The control terminal of the third transistor M3 is used to receive a third driving potential VG3. The first terminal of the third transistor M3 is coupled to the ground potential VSS. The second terminal of the third transistor M3 is coupled to the fifth node N5.

The tunable inductor element 250 includes a fourth transistor M4 and a resonant inductor LR. For example, the fourth transistor M4 can be an N-type metal oxide semiconductor field effect transistor. The resonant inductor LR has a first terminal and a second terminal. The first terminal of the resonant inductor LR is coupled to the fifth node N5 to receive the switching potential VW, and the second terminal of the resonant inductor LR is coupled to the sixth node N6. The fourth transistor M4 has a control terminal (e.g., a gate), a first terminal (e.g., a source), and a second terminal (e.g., a drain). The control terminal of the fourth transistor M4 is used to receive a first control potential VC1. The first terminal of the fourth transistor M4 is coupled to the sixth node N6, and the second terminal of the fourth transistor M4 is coupled to the fifth node N5.

Transformer 260 includes a main coil 261, a first secondary coil 262, and a second secondary coil 263. Transformer 260 further includes a built-in magnetizing inductor LM. Magnetizing inductor LM may be an inherent component inherent to transformer 260 during its manufacture, rather than an external, independent component. Main coil 261 and magnetizing inductor LM may be located on the same side of transformer 260 (e.g., the primary side), while first secondary coil 262 and second secondary coil 263 may be located on an opposite side of transformer 260 (e.g., the secondary side, which may be isolated from the primary side). The main coil 261 has a first end and a second end, wherein the first end of the main coil 261 is coupled to the sixth node N6, and the second end of the main coil 261 is coupled to the seventh node N7. The excitation inductor LM has a first end and a second end, wherein the first end of the excitation inductor LM is coupled to the sixth node N6, and the second end of the excitation inductor LM is coupled to the seventh node N7. The resonant capacitor CR has a first end and a second end, wherein the first end of the resonant capacitor CR is coupled to the seventh node N7, and the second end of the resonant capacitor CR is coupled to the ground potential VSS. The first auxiliary coil 262 has a first end and a second end, wherein the first end of the first auxiliary coil 262 is coupled to the eighth node N8, and the second end of the first auxiliary coil 262 is coupled to a common node NCM. For example, the common node NCM can provide a common potential, which can be considered another ground potential and can be the same as or different from the aforementioned ground potential VSS. The second sub-coil 263 has a first end and a second end, wherein the first end of the second sub-coil 263 is coupled to the common node NCM, and the second end of the second sub-coil 263 is coupled to a ninth node N9.

The adjustable resistance element 270 includes a fifth transistor M5 and a resonant resistor RR. For example, the fifth transistor M5 can be an N-type metal oxide semiconductor field effect transistor. The resonant resistor RR has a first terminal and a second terminal. The first terminal of the resonant resistor RR is coupled to a tenth node N10, and the second terminal of the resonant resistor RR is coupled to the ground potential VSS. The fifth transistor M5 has a control terminal (e.g., a gate), a first terminal (e.g., a source), and a second terminal (e.g., a drain). The control terminal of the fifth transistor M5 is used to receive a second control potential VC2. The first terminal of the fifth transistor M5 is coupled to the tenth node N10, and the second terminal of the fifth transistor M5 is coupled to the seventh node N7.

The second output stage circuit 280 includes a sixth diode D6, a seventh diode D7, and a second capacitor C2. The sixth diode D6 has an anode and a cathode, wherein the anode of the sixth diode D6 is coupled to the eighth node N8, and the cathode of the sixth diode D6 is coupled to the output node NOUT. The seventh diode D7 has an anode and a cathode, wherein the anode of the seventh diode D7 is coupled to the ninth node N9, and the cathode of the seventh diode D7 is coupled to the output node NOUT. The second capacitor C2 has a first terminal and a second terminal, wherein the first terminal of the second capacitor C2 is coupled to the output node NOUT, and the second terminal of the second capacitor C2 is coupled to the common node NCM.

The detection and control circuit 290 includes a microcontroller unit (MCU) 291, a sensing circuit 292, an averaging circuit 293, a first comparator 294, a second comparator 295, a first linear optical coupler 296, a second linear optical coupler 297, a first amplifier 298, a second amplifier 299, a third capacitor C3, and a fourth capacitor C4.

Microcontroller 291 can generate a first threshold potential VTH1, a second threshold potential VTH2, a first drive potential VG1, a second drive potential VG2, and a third drive potential VG3. For example, first drive potential VG1 can be maintained at a fixed potential when power supply 200 is initialized, and can provide a periodic time pulse waveform after power supply 200 enters normal operation. Second drive potential VG2 and third drive potential VG3 can have complementary logical levels. Furthermore, first threshold potential VTH1 and second threshold potential VTH2 are both fixed DC potentials, with first threshold potential VTH1 being higher than second threshold potential VTH2.

The sensing circuit 292 can detect the potential difference ΔV across the sensing resistor RS to generate a sensed potential VS. In some embodiments, the sensing circuit 292 is implemented by an auxiliary transformer. For example, the auxiliary transformer may include a first coil 292A and a second coil 292B, which may be located on different sides of the auxiliary transformer. Specifically, the first coil 292A has a first end and a second end, wherein the first end of the first coil 292A is coupled to the second node N2, and the second end of the first coil 292A is coupled to the third node N3. The second coil 292B has a first end and a second end, wherein the first end of the second coil 292B is used to output the sensed potential VS, and the second end of the second coil 292B is coupled to the ground potential VSS. It should be understood that the sensed potential VS is proportional to the potential difference ΔV. However, the present invention is not limited thereto. In other embodiments, the sensing circuit 292 may be implemented by two mutually coupled inductors (not shown).

The averaging circuit 293 can calculate an average value of the sensed potential VS and generate an average potential VA. For example, the average potential VA can represent an average level of the sensed potential VS over a given period of time, but is not limited thereto.

The first comparator 294 has a positive input, a negative input, and an output. The positive input of the first comparator 294 is configured to receive a first threshold potential VTH1, the negative input of the first comparator 294 is configured to receive an average potential VA, and the output of the first comparator 294 is configured to output a first comparison potential VB1. For example, if the average potential VA is lower than or equal to the first threshold potential VTH1, the first comparator 294 may output a first comparison potential VB1 having a high logic level. Conversely, if the average potential VA is higher than the first threshold potential VTH1, the first comparator 294 may output a first comparison potential VB1 having a low logic level.

The second comparator 295 has a positive input, a negative input, and an output. The positive input of the second comparator 295 is configured to receive the second threshold potential VTH2, the negative input of the second comparator 295 is configured to receive the average potential VA, and the output of the second comparator 295 is configured to output a second comparison potential VB2. For example, if the average potential VA is lower than or equal to the second threshold potential VTH2, the second comparator 295 may output the second comparison potential VB2 having a high logic level. Conversely, if the average potential VA is higher than the second threshold potential VTH2, the second comparator 295 may output the second comparison potential VB2 having a low logic level.

For example, the first linear optical coupler 296 can be implemented using a PCX electronic component. Specifically, the first linear optical coupler 296 includes a first light-emitting diode DL1 and a first bipolar junction transistor Q1 (e.g., NPN type). The first light-emitting diode DL1 has an anode and a cathode. The anode of the first light-emitting diode DL1 is configured to receive a first reference potential VB1, while the cathode of the first light-emitting diode DL1 is coupled to the ground potential VSS. The first BJT Q1 has a collector and an emitter, wherein the collector of the first BJT Q1 is coupled to a first internal node NN1 to output a first feedback potential VF1, and the emitter of the first BJT Q1 is coupled to the common node NCM.

The third capacitor C3 has a first terminal and a second terminal, wherein the first terminal of the third capacitor C3 is coupled to the first internal node NN1, and the second terminal of the third capacitor C3 is coupled to the common node NCM. In addition, the first amplifier 298 can amplify the first feedback potential VF1 by a first gain multiplier K1 to generate the aforementioned first control potential VC1. In some embodiments, the first gain multiplier K1 can be greater than or equal to 5, and the first amplifier 298 can operate according to the following equation (1):

………………………………………(1) “VC1” represents the level of the first control potential VC1, “K1” represents the value of the first gain multiplier K1, and “VF1” represents the level of the first feedback potential VF1.

For example, the second linear optical coupler 297 can be implemented using another PCX electronic component. Specifically, the second linear optical coupler 297 includes a second light-emitting diode DL2 and a second bipolar junction transistor Q2 (e.g., NPN type). The second light-emitting diode DL2 has an anode and a cathode. The anode of the second light-emitting diode DL2 is configured to receive the second reference potential VB2, while the cathode of the second light-emitting diode DL2 is coupled to the ground potential VSS. The second BJT Q2 has a collector and an emitter, wherein the collector of the second BJT Q2 is coupled to a second internal node NN2 to output a second feedback potential VF2, and the emitter of the second BJT Q2 is coupled to the common node NCM.

The fourth capacitor C4 has a first terminal and a second terminal, wherein the first terminal of the fourth capacitor C4 is coupled to the second internal node NN2, and the second terminal of the fourth capacitor C4 is coupled to the common node NCM. In addition, the second amplifier 299 can amplify the second feedback potential VF2 by a second gain factor K2 to generate the aforementioned second control potential VC2. In some embodiments, the second gain factor K2 can be greater than or equal to 5, and the second amplifier 299 can operate according to the following equation (2):

………………………………………(2) “VC2” represents the level of the second control potential VC2, “K2” represents the value of the second gain multiplier K2, and “VF2” represents the level of the second feedback potential VF2.

In some embodiments, the operating principle of the power supply 200 can be described as follows. The adjustable inductance element 250, the magnetizing inductor LM, the resonant capacitor CR, and the adjustable resistance element 270 together form a resonant tank of the power supply 200, wherein a resonant current IR flows through the resonant tank. In some embodiments, if the power supply 200 is used to drive a relatively heavy load, its resonant tank can be operated in an LLC mode to provide a large resonant energy. Alternatively, if the power supply 200 is used to drive a moderate load, its resonant tank can be operated in an LC mode to provide a moderate resonant energy. In other embodiments, if the power supply 200 is used to drive a relatively low load, its resonant tank can operate in an LCR mode to provide relatively low resonant energy. To define the three aforementioned modes, the first critical potential VTH1 can be defined based on 85% of the full-load output current of the power supply 200, while the second critical potential VTH2 can be defined based on 25% of the full-load output current of the power supply 200. For example, the first critical potential VTH1 can be approximately 4.25V, and the second critical potential VTH2 can be approximately 1.25V, but the present invention is not limited thereto. It should be noted that since the resonant tank of the power supply 200 can be dynamically adjusted according to different load conditions, the overall output stability of the power supply 200 can be further improved.

Figure 3 shows a waveform of the resonant current IR of the resonant tank of the power supply 200 according to one embodiment of the present invention when operating in LLC mode. The horizontal axis represents time (s) and the vertical axis represents current (A). If the potential difference ΔV across the sense resistor RS is relatively large, the corresponding average potential VA will be higher than the first threshold potential VTH1, causing the resonant tank of the power supply 200 to operate in LLC mode. At this time, the first control potential VC1 has a low logic level to disable the fourth transistor M4, and the second control potential VC2 also has a low logic level to disable the fifth transistor M5. In LLC mode, the resonant tank of the power supply 200 is composed of a resonant inductor LR, a magnetizing inductor LM, and a resonant capacitor CR.

Figure 4 shows a waveform of the resonant current IR of the resonant tank of the power supply 200 according to one embodiment of the present invention when operating in LC mode. The horizontal axis represents time (s) and the vertical axis represents current (A). If the potential difference ΔV across the sense resistor RS is relatively moderate, the corresponding average potential VA will be between the second threshold potential VTH2 and the first threshold potential VTH1, causing the resonant tank of the power supply 200 to operate in LC mode. At this time, the first control potential VC1 has a high logic level to enable the fourth transistor M4, while the second control potential VC2 has a low logic level to disable the fifth transistor M5. In the LC mode, the resonant tank of the power supply 200 is composed of the magnetizing inductor LM and the resonant capacitor CR.

Figure 5 shows a waveform of the resonant current IR of the resonant tank of the power supply 200 according to one embodiment of the present invention when operating in LCR mode. The horizontal axis represents time (s) and the vertical axis represents current (A). If the potential difference ΔV across the sense resistor RS is relatively small, the corresponding average potential VA will be lower than the second threshold potential VTH2, causing the resonant tank of the power supply 200 to operate in LCR mode. At this time, the first control potential VC1 has a high logic level, enabling the fourth transistor M4, and the second control potential VC2 also has a high logic level, enabling the fifth transistor M5. In the LCR mode, the resonant tank of the power supply 200 is composed of the magnetizing inductor LM, the resonant capacitor CR, and the resonant resistor RR.

In some embodiments, the three aforementioned operating modes of the resonant tank of the power supply 200 can be summarized as shown in Table 1 below: Average potential VA The first control potential VC1 The second control potential VC2 LLC model Low logic level Low logic level LC mode High logic level Low logic level LCR mode High logic level High logic level Table 1: Different operating modes of the resonance tank of the power supply

This invention proposes a novel power supply. Based on actual measurement results, the output stability of the power supply using the aforementioned design can be significantly enhanced, making it suitable for use in a variety of devices.

It is worth noting that the potential, current, resistance, inductance, capacitance, and other component parameters mentioned above are not limiting conditions of the present invention. Designers can adjust these settings according to different needs. The power supply of the present invention is not limited to the states shown in Figures 1-5. The present invention may only include any one or more features of any one or more embodiments of Figures 1-5. In other words, not all features shown in the diagrams need to be implemented in the power supply of the present invention at the same time. Although the embodiments of the present invention use metal oxide semiconductor field effect transistors as an example, the present invention is not limited to this. People in this technical field can use other types of transistors, such as junction field effect transistors, or fin field effect transistors, etc., without affecting the effects of the present invention.

In this specification and the scope of the patent application, ordinal numbers, such as "first", "second", "third", etc., have no sequential relationship with each other and are only used to mark and distinguish two different components with the same name.

Although the present invention is disclosed above with reference to preferred embodiments, they are not intended to limit the scope of the present invention. Anyone skilled in the art may make slight modifications and improvements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the scope of the attached patent application.

100,200: Power supply 110,210: Bridge rectifier 120,220: Power switch 130,230: First output stage circuit 140,240: Switching circuit 150,250: Adjustable inductor 160,260: Transformer 161,261: Primary coil 162,262: First secondary coil 163,263: Second secondary coil 170,270: Adjustable resistor 180,280: Second output stage circuit 190,290: Detection and control circuit 291: Microcontroller 292: Sensing circuit 292A: First coil 292B: Second coil 293: Averaging circuit 294: First comparator 295: Second comparator 296: First linear optocoupler 297: Second linear optocoupler 298: First amplifier 299: Second amplifier C1: First capacitor C2: Second capacitor C3: Third capacitor C4: Fourth capacitor CR: Resonance capacitor D1: First diode D2: Second diode D3: Third diode D4: Fourth diode D5: Fifth diode D6: Sixth diode D7: Seventh diode DL1: First LED DL2: Second LED IL: Inductor current IR: Resonance current K1: First gain factor K2: Second gain factor LM: Magnetizing inductor LR: Resonance inductor LU: Boost inductor M1: First transistor M2: Second transistor M3: Third transistor M4: Fourth transistor M5: Fifth transistor N1: First node N2: Second node N3: Third node N4: Fourth node N5: Fifth node N6: Sixth node N7: Seventh node N8: Eighth node N9: Ninth node N10: Tenth node NCM: Common node NIN1: First input node NIN2: Second input node NN1: First internal node NN2: Second internal node NOUT: Output node Q1: First bipolar junction transistor Q2: Second bipolar junction transistor RR: Resonance resistor RS: Sense resistor VA: Average voltage VB1: First comparison potential VB2: Second comparison potential VC1: First control potential VC2: Second control potential VE: Intermediate potential VF1: First feedback potential VF2: Second feedback potential VG1: First drive potential VG2: Second drive potential VG3: Third drive potential VIN1: First input potential VIN2: Second input potential VOUT: Output potential VR: Rectified potential VS: Sense potential VSS: Ground potential VTH1: First threshold potential VTH2: Second threshold potential VW: Switching potential ΔV: Potential difference

Figure 1 is a schematic diagram of a power supply according to an embodiment of the present invention. Figure 2 is a circuit diagram of a power supply according to an embodiment of the present invention. Figure 3 is a waveform diagram of the resonant current of the resonant tank of the power supply according to an embodiment of the present invention when operating in LLC mode. Figure 4 is a waveform diagram of the resonant current of the resonant tank of the power supply according to an embodiment of the present invention when operating in LC mode. Figure 5 is a waveform diagram of the resonant current of the resonant tank of the power supply according to an embodiment of the present invention when operating in LCR mode.

100: Power supply

110: Bridge rectifier

120: Power switch

130: First output stage circuit

140: Switching circuit

150: Adjustable inductor element

160: Transformer

161: Main coil

162: First coil

163: Second coil

170: Adjustable resistor element

180: Second output stage circuit

190: Detection and control circuit

CR: Resonant Capacitor

LM: Magnetizing Inductor

LU: Boost Inductor

RS: Sense resistor

VC1: First control voltage

VC2: Second control voltage

VE: intermediate potential

VG1: First driving potential

VG2: Second driving potential

VG3: Third drive potential

VIN1: First input potential

VIN2: Second input potential

VOUT: output voltage

VR: Rectification potential

VSS: Ground potential

VW: Switching potential

△V: potential difference

Claims (10)

A power supply with high output stability includes: a bridge rectifier generating a rectified potential based on a first input potential and a second input potential; a boost inductor receiving the rectified potential; a sense resistor coupled to the boost inductor; a power switch selectively coupling the sense resistor to a ground potential based on a first drive potential; a first output stage circuit coupled to the sense resistor and generating an intermediate potential; a switching circuit generating a switching potential based on the intermediate potential, a second drive potential, and a third drive potential; an adjustable inductor controlled by a first control potential; A transformer includes a main coil, a first secondary coil, and a second secondary coil, wherein the transformer has a built-in magnetizing inductor, and the main coil receives the switching potential via the adjustable inductance element; a resonant capacitor coupled to the magnetizing inductor; an adjustable resistance element coupled to the magnetizing inductor and controlled by a second control potential; a second output stage circuit coupled to the first secondary coil and the second secondary coil and generating an output potential; and a detection and control circuit that monitors a potential difference across the sense resistor and generates the first drive potential, the second drive potential, and the third drive potential. The detection and control circuit further generates the first control potential and the second control potential based on the potential difference. The power supply of claim 1, wherein the bridge rectifier comprises: a first diode having an anode and a cathode, wherein the anode of the first diode is coupled to a first input node to receive the first input potential, and the cathode of the first diode is coupled to a first node to output the rectified potential; a second diode having an anode and a cathode, wherein the anode of the second diode is coupled to a second input node to receive the second input potential, and the cathode of the second diode is coupled to the first node; a third diode having an anode and a cathode, wherein the anode of the third diode is coupled to the ground potential, and the cathode of the third diode is coupled to the first input node; and a fourth diode having an anode and a cathode, wherein the anode of the fourth diode is coupled to the ground potential, and the cathode of the fourth diode is coupled to the second input node; the boost inductor having a first terminal and a second terminal, wherein the first terminal of the boost inductor is coupled to the first node to receive the rectified potential, and the second terminal of the boost inductor is coupled to a second node; The sensing resistor has a first end and a second end, the first end of the sensing resistor is coupled to the second node, and the second end of the sensing resistor is coupled to a third node. The power supply of claim 2, wherein the power switch comprises: A first transistor having a control terminal, a first terminal, and a second terminal, wherein the control terminal of the first transistor is configured to receive the first drive potential, the first terminal of the first transistor is coupled to the ground potential, and the second terminal of the first transistor is coupled to the third node. The power supply of claim 2, wherein the first output stage circuit comprises: a fifth diode having an anode and a cathode, wherein the anode of the fifth diode is coupled to the third node, and the cathode of the fifth diode is coupled to a fourth node to output the intermediate potential; and a first capacitor having a first terminal and a second terminal, wherein the first terminal of the first capacitor is coupled to the fourth node, and the second terminal of the first capacitor is coupled to the ground potential. The power supply of claim 4, wherein the switching circuit comprises: a second transistor having a control terminal, a first terminal, and a second terminal, wherein the control terminal of the second transistor is configured to receive the second drive potential, the first terminal of the second transistor is coupled to a fifth node to output the switching potential, and the second terminal of the second transistor is coupled to the fourth node to receive the intermediate potential; and a third transistor having a control terminal, a first terminal, and a second terminal, wherein the control terminal of the third transistor is configured to receive the third drive potential, the first terminal of the third transistor is coupled to the ground potential, and the second terminal of the third transistor is coupled to the fifth node. The power supply of claim 5, wherein the adjustable inductance element comprises: a resonant inductor having a first terminal and a second terminal, wherein the first terminal of the resonant inductor is coupled to the fifth node to receive the switching potential, and the second terminal of the resonant inductor is coupled to a sixth node; and a fourth transistor having a control terminal, a first terminal, and a second terminal, wherein the control terminal of the fourth transistor is configured to receive the first control potential, the first terminal of the fourth transistor is coupled to the sixth node, and the second terminal of the fourth transistor is coupled to the fifth node. The power supply as described in claim 6, wherein the main coil has a first end and a second end, the first end of the main coil is coupled to the sixth node, the second end of the main coil is coupled to a seventh node, the excitation inductor has a first end and a second end, the first end of the excitation inductor is coupled to the sixth node, the second end of the excitation inductor is coupled to the seventh node, the resonant capacitor has a first end and a second end, the resonant capacitor has a first end and a second end, The first end is coupled to the seventh node, the second end of the resonant capacitor is coupled to the ground potential, the first secondary coil has a first end and a second end, the first end of the first secondary coil is coupled to an eighth node, the second end of the first secondary coil is coupled to a common node, the second secondary coil has a first end and a second end, the first end of the second secondary coil is coupled to the common node, and the second end of the second secondary coil is coupled to a ninth node. The power supply of claim 7, wherein the adjustable resistance element comprises: a resonant resistor having a first terminal and a second terminal, wherein the first terminal of the resonant resistor is coupled to a tenth node, and the second terminal of the resonant resistor is coupled to the ground potential; and a fifth transistor having a control terminal, a first terminal, and a second terminal, wherein the control terminal of the fifth transistor is configured to receive the second control potential, the first terminal of the fifth transistor is coupled to the tenth node, and the second terminal of the fifth transistor is coupled to the seventh node. The power supply of claim 7, wherein the second output stage circuit comprises: a sixth diode having an anode and a cathode, wherein the anode of the sixth diode is coupled to the eighth node, and the cathode of the sixth diode is coupled to an output node to output the output potential; a seventh diode having an anode and a cathode, wherein the anode of the seventh diode is coupled to the ninth node, and the cathode of the seventh diode is coupled to the output node; and a second capacitor having a first terminal and a second terminal, wherein the first terminal of the second capacitor is coupled to the output node, and the second terminal of the second capacitor is coupled to the common node. The power supply of claim 1, wherein the detection and control circuit comprises: a microcontroller that generates a first critical potential, a second critical potential, the first drive potential, the second drive potential, and the third drive potential, wherein the first critical potential is higher than the second critical potential; a sensing circuit that obtains the potential difference across the sensing resistor to generate a sensed potential; an averaging circuit that calculates an average value of the sensed potentials to generate an average potential; A first comparator having a positive input, a negative input, and an output, wherein the positive input of the first comparator is used to receive the first threshold potential, the negative input of the first comparator is used to receive the average potential, and the output of the first comparator is used to output a first comparison potential; A second comparator having a positive input, a negative input, and an output, wherein the positive input of the second comparator is used to receive the second threshold potential, the negative input of the second comparator is used to receive the average potential, and the output of the second comparator is used to output a second comparison potential; A first linear optical coupler includes a first light-emitting diode (LED) and a first bipolar junction transistor (BJT), wherein the first LED has an anode and a cathode, the anode of the first LED is used to receive the first reference potential, the cathode of the first LED is coupled to the ground potential, the first BJT has a collector and an emitter, the collector of the first BJT is coupled to a first internal node to output a first feedback potential, and the emitter of the first BJT is coupled to a common node; A second linear optical coupler comprising a second light-emitting diode and a second bipolar junction transistor, wherein the second light-emitting diode has an anode and a cathode, the anode of the second light-emitting diode is used to receive the second reference potential, the cathode of the second light-emitting diode is coupled to the ground potential, the second bipolar junction transistor has a collector and an emitter, the collector of the second bipolar junction transistor is coupled to a second internal node to output a second feedback potential, and the emitter of the second bipolar junction transistor is coupled to the common node; A third capacitor having a first terminal and a second terminal, wherein the first terminal of the third capacitor is coupled to the first internal node, and the second terminal of the third capacitor is coupled to the common node; A fourth capacitor having a first terminal and a second terminal, wherein the first terminal of the fourth capacitor is coupled to the second internal node, and the second terminal of the fourth capacitor is coupled to the common node; A first amplifier amplifies the first feedback potential by a first gain factor to generate the first control potential; and A second amplifier amplifies the second feedback potential by a second gain factor to generate the second control potential.