Chip power supply system and electronic equipment

Abstract

The invention provides a chip power supply system and electronic equipment, a high-voltage power taking end of a primary side control chip of the system is coupled to a primary side voltage input end through a power taking module, a power supply end of the primary side control chip is coupled to a first end of a power supply capacitor, and the first end of the power supply capacitor is further coupled to a first end of an auxiliary winding through a rectifier diode; the second end of the power supply capacitor is coupled to the second end of the auxiliary winding, the second end of the power supply capacitor is further grounded, and the primary side control chip is configured to determine the power supply mode of the primary side control chip according to the voltage value of the power supply end of the primary side control chip and the current flowing through the power transistor of the primary side circuit. Whether external charging is started or not is determined based on the voltage value of the high-voltage electricity taking end, only when external charging is started, the electricity taking module is connected, and the high-voltage electricity taking end is used for charging the power supply capacitor. Therefore, when the auxiliary winding is insufficient in power supply or the circuit breaks down, power can be safely supplied to the primary side control chip.

Description

Technical Field

[0001] The present invention relates to the field of power electronics, and in particular to a chip power supply system and electronic equipment. Background Art

[0002] With the rapid development of modern electronic products towards low power consumption and high efficiency, low-power standby design has become an important requirement for energy conservation and environmental protection. In particular, power consumption control in standby mode has gradually become a key indicator in switching power supply design.

[0003] When the system is operating in zero-watt standby mode, in order to ensure that the primary-side control chip does not restart due to power failure, the standby power supply usually adopts the following power supply strategy: real-time monitoring of the supply voltage of the primary-side control chip. When VDD is lower than the set voltage, the primary-side control chip outputs a power tube drive signal to drive the primary-side power tube switch, so that energy is transferred through the transformer to the auxiliary winding connected to the power supply end of the primary-side control chip, thereby preventing the primary-side control chip from powering off.

[0004] However, if an abnormality occurs at the power supply end of the primary control chip, for example, the voltage at the power supply end of the primary control chip is always lower than the set voltage, the primary control chip will continue to output the power tube drive signal, causing the DC output voltage on the secondary side to continue to rise without feedback control. This DC output voltage may exceed the withstand voltage of the output capacitor, posing a safety hazard.

[0005] Therefore, how to power the primary-side control chip while ensuring safety has become a technical problem that the industry urgently needs to solve. Summary of the Invention

[0006] The present invention provides a chip power supply system and electronic equipment, which solve the technical problem of how to power a primary-side control chip while ensuring safety.

[0007] According to a first aspect of the present invention, an embodiment of the present invention provides a chip power supply system, which is applied to a primary-side control chip of an AC / DC power converter. The AC / DC power converter includes a primary circuit, a transformer, and a secondary circuit coupled in sequence. The transformer includes a primary winding, an auxiliary winding, and a secondary winding. The primary circuit includes a rectifier module, an RCD module, the power transistor, and a sampling resistor. A first end of the primary winding is coupled to a primary voltage input terminal through the rectifier module, and a second end thereof is grounded in sequence through a power transistor and a sampling resistor. The second end thereof is also coupled to the first end of the primary winding through the RCD module.

[0008] The high-voltage power supply terminal of the primary control chip is coupled to the primary voltage input terminal through the power supply module, and its power supply terminal is coupled to the first terminal of the power supply capacitor. The first terminal of the power supply capacitor is also coupled to the first terminal of the auxiliary winding through a rectifier diode. The second terminal of the power supply capacitor is coupled to the second terminal of the auxiliary winding. The second terminal of the power supply capacitor is also grounded. The current sampling terminal of the primary control chip is coupled to the first terminal of the sampling resistor; wherein:

[0009] The primary side control chip includes:

[0010] a power supply voltage sampling module, coupled to the power supply terminal, for acquiring the voltage value of the power supply terminal of the primary side control chip in real time and outputting a first signal;

[0011] a current sampling module, coupled to the current sampling terminal, configured to obtain a current flowing through the power transistor of the primary circuit and output a second signal;

[0012] High-voltage power supply module, including:

[0013] a high-voltage power supply sampling unit, coupled to the high-voltage power terminal, for acquiring a voltage value of the high-voltage power terminal in real time and outputting a third signal;

[0014] a main control unit, configured to determine a power supply mode of the primary control chip based at least on the first signal and the second signal, determine whether to start or stop external charging based on the first signal, the power supply mode, and the third signal, and output a fourth signal, wherein the power supply mode includes an auxiliary winding power supply mode and an external power supply mode;

[0015] The high-voltage power supply unit is coupled to the power supply end and the high-voltage power supply end respectively, and its control end receives the fourth signal, and is used to connect the power supply module when the fourth signal indicates that external charging is turned on, and use the high-voltage power supply end to charge the power supply capacitor.

[0016] Optionally, the method for determining whether to start and stop external charging based on the first signal, the power supply mode, and the third signal includes:

[0017] When the power supply mode is the auxiliary winding power supply mode, stopping external charging;

[0018] When the power supply mode is the external power supply mode, starting and stopping the external charging are determined based on the voltage represented by the first signal and the third signal, wherein:

[0019] If the voltage represented by the first signal is less than a first lower threshold voltage, and the voltage represented by the third signal is less than a third threshold voltage, external charging is started; otherwise, external charging is stopped.

[0020] Optionally, the method for determining the power supply mode of the primary-side control chip based on the first signal and the second signal includes:

[0021] determining an operating mode of the AC / DC power converter based on the second signal, the operating mode including a normal operating mode and a sleep mode;

[0022] The power supply mode of the primary control chip is determined based on the operating mode and the first signal, wherein:

[0023] When the operating mode is the normal operating mode, if the voltage represented by the first signal is greater than or equal to a first lower threshold voltage and less than or equal to a first upper threshold voltage, determining that the power supply mode of the primary control chip is the auxiliary winding power supply mode;

[0024] When the operating mode is the normal operating mode, if the voltage represented by the first signal is less than a first lower threshold voltage or greater than a first upper threshold voltage, determining that the power supply mode of the primary control chip is the external power supply mode;

[0025] When the working mode is the sleep mode, if the voltage represented by the first signal is less than a first lower threshold voltage, the power supply mode of the primary control chip is determined to be the external power supply mode; otherwise, it is the auxiliary winding power supply mode.

[0026] Optionally, the method for determining the operating mode of the AC / DC power converter based on the second signal includes:

[0027] If the voltage represented by the second signal is less than a second threshold voltage, determining that the operating mode of the AC / DC power converter is a sleep mode;

[0028] If the voltage represented by the second signal is greater than or equal to a second threshold voltage, it is determined that the operating mode of the AC / DC power converter is a normal operating mode.

[0029] Optionally, the primary-side control chip further includes a feedback terminal, and the feedback terminal is used to obtain the output voltage of the secondary-side circuit;

[0030] The overall control unit is further configured to determine a power supply mode of the primary-side control chip based on the output voltage of the secondary-side circuit, including:

[0031] When the operating mode is the normal operating mode, if the voltage output by the secondary circuit is less than a fourth lower threshold voltage or greater than a fourth upper threshold voltage, determining that the power supply mode of the primary control chip is the external power supply mode;

[0032] When the working mode is the sleep mode, if the voltage output by the secondary circuit is less than a fourth lower threshold voltage, it is determined that the power supply mode of the primary control chip is the external power supply mode.

[0033] Optionally, the gate output terminal of the general control unit is coupled to the control terminal of the power transistor to output a gate drive signal to the control terminal of the power transistor, wherein the gate drive signal includes a first drive signal and a second drive signal;

[0034] The main control unit is also used to:

[0035] When the working mode is the sleep mode, if the voltage output by the secondary circuit is less than the fifth threshold voltage, a first drive signal is output to the control end of the power transistor to transfer electrical energy to the secondary circuit; otherwise, a second drive signal is output to the control end of the power transistor to control the power transistor to be disconnected.

[0036] Optionally, the secondary circuit includes an output capacitor and a synchronous rectifier MOS tube, and the power converter further includes an optocoupler unit: wherein:

[0037] The first end of the secondary winding is coupled to the first end of the output capacitor through the synchronous rectifier MOS transistor, the second end of the output capacitor is grounded, and the output capacitor supplies power to the connected load;

[0038] The first end of the optical coupling unit is coupled to the first end of the output capacitor, and the second end of the optical coupling unit is coupled to the feedback end of the primary side control chip;

[0039] The optical coupling unit is configured to obtain and feed back to the primary-side control chip the voltage output by the secondary-side circuit.

[0040] Optionally, the power taking module includes a clamping unit, a power taking resistor and a filter capacitor;

[0041] The first input terminal and the second input terminal of the clamping unit are respectively coupled to the first primary voltage input terminal and the second primary voltage input terminal, and the output terminal thereof is coupled to the high-voltage power supply terminal of the primary control chip through the power supply resistor, and the high-voltage power supply terminal is grounded through the filter capacitor.

[0042] Optionally, the clamping unit includes a forward clamping diode and a negative clamping diode;

[0043] The positive electrode of the forward clamping diode is coupled to the first primary voltage input terminal, the positive electrode of the negative clamping diode is coupled to the second primary voltage input terminal, the negative electrode of the forward clamping diode and the negative electrode of the negative clamping diode are coupled through a first node, and the first node is also coupled to the high-voltage power supply terminal of the primary control chip through the power supply resistor.

[0044] Optionally, the high-voltage power supply unit includes a pull-down constant current source;

[0045] The first end of the pull-down constant current source is coupled to the high-voltage power supply end, the second end thereof is coupled to the power supply end, and the control end thereof is used to receive the fourth signal, wherein, when the fourth signal indicates that external charging is turned on, the pull-down constant current source outputs a constant current to connect the power supply module.

[0046] Optionally, the chip power supply system further includes a first voltage-dividing resistor and a second voltage-dividing resistor;

[0047] The first end of the first voltage-dividing resistor and the first end of the second voltage-dividing resistor are both coupled to the power supply voltage sampling module, the second end of the first voltage-dividing resistor is coupled to the first end of the power supply capacitor, and the second end of the second voltage-dividing resistor is grounded.

[0048] According to a second aspect of the present invention, an embodiment of the present invention provides an electronic device, comprising the chip power supply system as described in any one of the first aspects of the present invention.

[0049] Compared with the prior art, the technical solution of the embodiment of the present invention has the following beneficial effects:

[0050] In the chip power supply system and electronic device of the technical solution of the present invention, the high-voltage power supply end of the primary control chip is coupled to the primary voltage input end through the power supply module, and its power supply end is coupled to the first end of the power supply capacitor, the first end of the power supply capacitor is also coupled to the first end of the auxiliary winding through the rectifier diode, the second end of the power supply capacitor is coupled to the second end of the auxiliary winding, and the second end of the power supply capacitor is also grounded. The primary control chip is configured to determine the power supply mode of the primary control chip based on the voltage value of the power supply end of the primary control chip and the current of the power transistor flowing through the primary circuit, and then determine whether to turn on external charging based on the voltage value of the high-voltage power supply end. Only when external charging is turned on, the power supply module is connected and the power supply capacitor is charged using the high-voltage power supply end. Therefore, the present invention can safely power the primary control chip when the auxiliary winding is underpowered or a circuit failure occurs.

[0051] Furthermore, the method for determining whether to start and stop external charging based on the first signal, the power supply mode, and the third signal includes: stopping external charging when the power supply mode is the auxiliary winding power supply mode; and determining whether to start and stop external charging based on the voltages represented by the first signal and the third signal when the power supply mode is the external power supply mode, wherein: if the voltage represented by the first signal is less than a first lower threshold voltage and the voltage represented by the third signal is less than a third threshold voltage, external charging is started; otherwise, external charging is stopped. Thus, the present invention not only safely powers the primary control chip when the auxiliary winding power supply is insufficient or a circuit fault occurs, but also activates external charging only when the AC voltage at the primary voltage input terminal reaches a valley, reducing AC voltage input loss and thus meeting the 0mW low standby requirement.

[0052] Furthermore, the gate output terminal of the master control unit is coupled to the control terminal of the power transistor to output a gate drive signal to the control terminal of the power transistor, wherein the gate drive signal includes a first drive signal and a second drive signal. The master control unit is further configured to: when the operating mode is the sleep mode, if the voltage output by the secondary circuit is less than a fifth threshold voltage, output the first drive signal to the control terminal of the power transistor to transfer power to the secondary circuit; otherwise, output the second drive signal to the control terminal of the power transistor to control the power transistor to disconnect. Thus, the present invention ensures that the output voltage will not restart due to power outages. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0054] Figure 1 It is a schematic diagram of the structure of the chip power supply system in the prior art;

[0055] Figure 2 This is the working waveform of the chip power supply system in the existing technology Figure 1 ;

[0056] Figure 3 This is the working waveform of the chip power supply system in the existing technology Figure 2 ;

[0057] Figure 4 This is the working waveform of the chip power supply system in the existing technology Figure 3 ;

[0058] Figure 5This is a schematic diagram of the structure of the chip power supply system provided by the embodiment of the present invention. Figure 1 ;

[0059] Figure 6 This is a schematic diagram of the structure of the primary side control chip provided by an embodiment of the present invention. Figure 1 ;

[0060] Figure 7 This is a working waveform diagram of the chip power supply system provided by an embodiment of the present invention;

[0061] Figure 8 This is a schematic diagram of the structure of the primary side control chip provided by an embodiment of the present invention. Figure 2 ;

[0062] Figure 9 This is a schematic diagram of the structure of the chip power supply system provided by the embodiment of the present invention. Figure 2 ;

[0063] Figure 10 This is a schematic diagram of the structure of the chip power supply system provided by the embodiment of the present invention. Figure 3 ;

[0064] Figure 11 This is a schematic diagram of the structure of the chip power supply system provided by the embodiment of the present invention. Figure 4 .

[0065] Reference numerals:

[0066] 11-rectifier module;

[0067] 12-RCD module;

[0068] R1-sampling resistor;

[0069] Np-primary winding;

[0070] Naux-auxiliary winding;

[0071] Ns-secondary winding;

[0072] Cout-output capacitance;

[0073] Q2-synchronous rectifier MOS tube;

[0074] 10-primary side control chip;

[0075] FB-feedback terminal;

[0076] 2-Secondary circuit;

[0077] HV-high voltage power terminal;

[0078] 13-power supply module;

[0079] Cin-power supply capacitor;

[0080] D3-rectifier diode;

[0081] FAULT-fault mode pin;

[0082] 101-power supply voltage sampling module;

[0083] VDD-power supply terminal;

[0084] 102-current sampling module;

[0085] CS-current sampling terminal;

[0086] Q1 - power transistor;

[0087] 1031-high voltage power supply sampling unit;

[0088] HV-high voltage power terminal;

[0089] 1032- main control unit;

[0090] 1033-high voltage power supply unit;

[0091] D1- forward clamping diode;

[0092] D2-negative clamping diode;

[0093] 104-output voltage sampling unit. DETAILED DESCRIPTION

[0094] The following will provide a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0095] The terms "first," "second," "third," "fourth," and the like (if any) in the description and claims of the present invention and in the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a particular order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. In addition, the terms "including" and "having," as well as any variations thereof, are intended to cover non-exclusive inclusions, e.g., a process, method, system, product, or apparatus comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to these processes, methods, products, or apparatus.

[0096] The technical solution of the present invention is described in detail below with reference to specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described in detail in some embodiments.

[0097] As described in the background art, it is difficult to power the primary-side control chip while ensuring safety in the existing technology. This will be described in detail below with reference to the accompanying drawings.

[0098] Figure 1 The diagram is a structural diagram of a flyback AC / DC power converter.

[0099] exist Figure 1 In an example, the AC / DC power converter includes a primary circuit, a transformer, and a secondary circuit coupled in sequence, wherein the transformer includes a primary winding Np, an auxiliary winding Naux, and a secondary winding Ns;

[0100] The primary circuit includes a rectifier module 11, an RCD module 12, a power transistor Q1 and a sampling resistor R1;

[0101] A first end of the primary winding Np is coupled to the primary voltage input terminal AC_IN through the rectifier module 11, and a second end thereof is grounded through the power transistor Q1 and the sampling resistor R1 in sequence, and a second end thereof is further coupled to the first end of the primary winding Np through the RCD module 12;

[0102] The secondary circuit includes an output capacitor Cout and a synchronous rectifier MOS tube Q2, and the power converter also includes an optical coupler unit 21:

[0103] The first end of the secondary winding Ns is coupled to the first end of the output capacitor Cout through the synchronous rectifier MOS transistor Q2, the second end of the output capacitor Cout is grounded, and the output capacitor Cout supplies power to the connected load;

[0104] A first end of the optical coupling unit 21 is coupled to a first end of the output capacitor Cout, and a second end of the optical coupling unit 21 is coupled to a feedback end FB of the primary side control chip 10;

[0105] The optical coupling unit 21 is configured to obtain and feed back the voltage DC_OUT output by the secondary circuit to the primary control chip 10 .

[0106] When the system is operating in zero-watt standby mode, in order to ensure that the secondary-side output voltage DC_OUT and the primary-side control chip 10 will not restart due to power outage, the standby power supply generally adopts the following power supply strategy:

[0107] Please refer to Figure 1 as well as Figure 2 , Figure 2 shows the corresponding waveforms of the output voltage DC_OUT of the secondary circuit and the gate drive signal GATE;

[0108] It can be seen that this embodiment monitors the output voltage DC_OUT of the secondary circuit in real time through the optocoupler unit 21. When the output voltage DC_OUT is lower than the first lower threshold voltage Vo_ref1, the primary chip outputs the gate drive signal GATE to drive the primary MOS tube switch. Then, the energy is transferred to the secondary side through the transformer to prevent the secondary output voltage DC_OUT from powering off. When the output voltage DC_OUT is greater than or equal to the first upper threshold voltage Vo_ref2, the primary chip stops outputting the gate drive signal GATE to prevent the secondary output voltage DC_OUT from being too high.

[0109] Please refer to Figure 1 as well as Figure 3 , Figure 3 shows the corresponding waveforms of the power supply voltage VDD and the gate drive signal GATE of the primary side control chip 10;

[0110] As can be seen, this embodiment monitors the supply voltage VDD of the primary control chip 10 in real time. When VDD is lower than the set voltage VDD_ref1, the primary control chip 10 outputs the gate drive signal GATE to drive the primary power tube switch Q1, so that energy is transferred through the auxiliary winding Naux connected to the power supply terminal VDD of the primary control chip 10 of the transformer, thereby preventing the primary control chip 10 from powering off.

[0111] When the power supply voltage VDD is greater than or equal to another set voltage VDD_ref2, the primary chip stops outputting the gate driving signal GATE to prevent the voltage of the power supply terminal VDD from being too high.

[0112] However, please refer to Figure 4 , Figure 4 shows the corresponding waveforms of the power supply voltage VDD, the output voltage DC_OUT and the gate drive signal GATE;

[0113] It can be seen that in this embodiment, if the power supply terminal VDD of the primary side control chip 10 is abnormal, for example, when the power supply terminal VDD voltage of the primary side control chip 10 is always lower than the set voltage VDD_ref1, the primary side control chip 10 will continue to output the gate drive signal GATE, causing the DC output voltage DC_OUT on the secondary side to continue to increase without feedback control. The DC output voltage DC_OUT may exceed the withstand voltage of the output capacitor Cout, posing a safety hazard.

[0114] In view of this, an embodiment of the present invention provides a chip power supply system, in which the high-voltage power supply terminal of the primary control chip of the system is coupled to the primary voltage input terminal through a power supply module, the power supply terminal is coupled to the first end of the power supply capacitor, the first end of the power supply capacitor is also coupled to the first end of the auxiliary winding through a rectifier diode, the second end of the power supply capacitor is coupled to the second end of the auxiliary winding, the second end of the power supply capacitor is also grounded, and the current sampling terminal of the primary control chip is coupled to the first end of the sampling resistor; the primary control chip is configured to determine the power supply mode of the primary control chip based on the voltage value of the power supply terminal of the primary control chip, the current flowing through the power transistor of the primary circuit, and the voltage value of the high-voltage power supply terminal, and only when the power supply mode is the external power supply mode, the power supply module is connected to charge the power supply capacitor using the high-voltage power supply terminal. Therefore, the present invention can safely power the primary control chip when the auxiliary winding is underpowered or a circuit failure occurs.

[0115] In one embodiment, please refer to Figure 5 An embodiment of the present invention provides a chip power supply system, which is applied to a primary-side control chip 10 of an AC / DC power converter. The AC / DC power converter includes a primary circuit, a transformer, and a secondary circuit 2 coupled in sequence. The transformer includes a primary winding Np, an auxiliary winding Naux, and a secondary winding Ns. The primary circuit includes a rectifier module 11, an RCD module 12, the power transistor Q1, and a sampling resistor R1. A first end of the primary winding Np is coupled to a primary voltage input terminal AC_IN through the rectifier module 11, and a second end thereof is grounded through the power transistor Q1 and the sampling resistor R1 in sequence. The second end thereof is also coupled to the first end of the primary winding Np through the RCD module 12.

[0116] The high-voltage power supply terminal HV of the primary-side control chip 10 is coupled to the primary-side voltage input terminal AC_IN through the power supply module 13, and its power supply terminal VDD is coupled to the first terminal of the power supply capacitor Cin. The first terminal of the power supply capacitor Cin is also coupled to the first terminal of the auxiliary winding Naux through the rectifier diode D3. The second terminal of the power supply capacitor Cin is coupled to the second terminal of the auxiliary winding Naux. The second terminal of the power supply capacitor Cin is also grounded GND. The current sampling terminal CS of the primary-side control chip 10 is coupled to the first terminal of the sampling resistor R1; wherein:

[0117] Please continue to refer to Figure 6 The primary side control chip 10 includes:

[0118] The power supply voltage sampling module 101 is coupled to the power supply terminal VDD, and is used to obtain the voltage value of the power supply terminal VDD of the primary side control chip 10 in real time and output a first signal;

[0119] a current sampling module 102 coupled to the current sampling terminal CS, configured to obtain the current flowing through the power transistor Q1 of the primary circuit and output a second signal;

[0120] High-voltage power supply module, including:

[0121] a high-voltage power supply sampling unit 1031, coupled to the high-voltage power terminal HV, for acquiring a voltage value of the high-voltage power terminal HV in real time and outputting a third signal;

[0122] a main control unit 1032, configured to determine a power supply mode of the primary control chip 10 based at least on the first signal and the second signal, determine whether to start or stop external charging based on the first signal, the power supply mode, and the third signal, and output a fourth signal, wherein the power supply mode includes an auxiliary winding power supply mode and an external power supply mode;

[0123] The high-voltage power supply unit 1033 is coupled to the power supply terminal VDD and the high-voltage power supply terminal HV respectively, and its control terminal receives the fourth signal, and is used to connect the power supply module 13 when the fourth signal indicates that external charging is turned on, and use the high-voltage power supply terminal HV to charge the power supply capacitor Cin.

[0124] Therefore, the present invention can determine the state of the circuit based on at least the first signal, the second signal and the third signal, so that when the auxiliary winding Naux is underpowered or a circuit failure occurs, the primary control chip 10 can be safely powered by the voltage of the primary voltage input terminal AC_IN.

[0125] In practical applications, please refer to Figure 5 The primary side control chip also includes a fault mode pin FAULT, which is used to control the chip to be turned on and off. When a fault occurs in the system that cannot be regulated by the power tube, the chip is turned on and off.

[0126] Specifically, if the fault mode is triggered by the fault mode pin FAULT, the primary side control chip will be powered off and the GATE pin will stop outputting signals; if the fault mode is not triggered by the fault mode pin FAULT, the chip will operate normally according to the method provided in the embodiment of the present invention.

[0127] The external power supply mode of the present invention is now described.

[0128] In one embodiment, the method for determining whether to start or stop external charging based on the first signal, the power supply mode, and the third signal includes:

[0129] When the power supply mode is the auxiliary winding power supply mode, stopping external charging;

[0130] When the power supply mode is the external power supply mode, starting and stopping the external charging are determined based on the voltage represented by the first signal and the third signal, wherein:

[0131] If the voltage represented by the first signal is less than a first lower threshold voltage, and the voltage represented by the third signal is less than a third threshold voltage, external charging is started; otherwise, external charging is stopped.

[0132] In a specific implementation, please refer to Figure 5 , the power taking module 13 includes a clamping unit, a power taking resistor R2 and a filter capacitor C1;

[0133] The first input terminal and the second input terminal of the clamping unit are coupled to the first primary voltage input terminal and the second primary voltage input terminal respectively, and the output terminal thereof is coupled to the high voltage power supply terminal HV of the primary control chip 10 through the power supply resistor R2, and the high voltage power supply terminal HV is grounded through the filter capacitor C1.

[0134] In an actual workbench, by adjusting the resistance of the power-taking resistor R2, the magnitude of the current charging the filter capacitor on this path can be adjusted.

[0135] As an example, please refer to Figure 5 , the clamping unit includes a forward clamping diode D1 and a negative clamping diode D2;

[0136] The anode of the forward clamping diode D1 is coupled to the first primary voltage input terminal, the anode of the negative clamping diode D2 is coupled to the second primary voltage input terminal, the cathode of the forward clamping diode D1 and the cathode of the negative clamping diode D2 are coupled through a first node, and the first node is also coupled to the high-voltage power terminal HV of the primary control chip 10 through the power-taking resistor R2.

[0137] The voltage waveform of the first node can be as follows Figure 7 As shown, in Figure 7 In the example, it also shows the voltage waveform of the power supply terminal VDD of the primary side control chip 10 and the waveform of the fourth signal in the sleep mode, wherein:

[0138] VDD_ref1 can be understood as the first lower threshold voltage;

[0139] VDD_ref2 can be understood as the first upper threshold voltage;

[0140] HV_enb can be understood as the third threshold voltage.

[0141] It can be seen that the present invention reduces the input loss of the AC voltage by setting the external power supply mode to be enabled only when the AC voltage at the primary voltage input terminal AC_IN is in the valley region, so as to meet the 0mW low standby requirement.

[0142] The specific working modes of the power supply voltage sampling module 101 and the current sampling module 102 in the primary side control chip 10 are now described.

[0143] Regarding the high voltage power supply unit 1033, in a specific implementation, please refer to Figure 8 , the high voltage power supply unit 1033 includes a pull-down constant current source;

[0144] The first end of the pull-down constant current source is coupled to the high-voltage power supply terminal HV, the second end thereof is coupled to the power supply terminal VDD, and the control end thereof is used to receive the fourth signal, wherein, when the fourth signal indicates that external charging is turned on, the pull-down constant current source outputs a constant current to connect the power supply module 13.

[0145] Please refer to Figure 8 In a specific embodiment, the power supply voltage sampling module 101 can be coupled to the power supply end VDD through the zero current detection pin ZCD of the primary side control chip 10, so as to obtain the voltage value of the power supply end VDD of the primary side control chip 10 in real time (that is, detect the voltage on the auxiliary winding Naux power supply branch). The voltage value represented by the first signal can be used to determine the state of the auxiliary winding Naux power supply voltage VDD (such as normal, off, too high, etc.), thereby realizing the sampling of the VDD voltage value.

[0146] In this case, the chip power supply system further includes a first voltage dividing resistor Rup and a second voltage dividing resistor Rdown;

[0147] The first end of the first voltage-dividing resistor Rup and the first end of the second voltage-dividing resistor Rdown are both coupled to the power supply voltage sampling module 101 (i.e., ZCD), the second end of the first voltage-dividing resistor Rup is coupled to the first end of the power supply capacitor Cin, and the second end of the second voltage-dividing resistor Rdown is grounded.

[0148] Please continue to refer to Figure 8 ,exist Figure 8 In the example, the current sampling module 102 is coupled to the current sampling terminal CS, which is equivalent to detecting the current on the power transistor and the primary branch of the transformer. The current value represented by the second signal can be used to determine the working state of the circuit (such as heavy load, light load, etc.), thereby realizing the detection of the load state of the circuit.

[0149] exist Figure 8In the example, the current sampling module 102 is further coupled to the second end of the power transistor through the third resistor R3, and detects the current in the power transistor and the primary branch of the transformer by obtaining the voltage value on the third resistor.

[0150] Of course, the present invention does not limit the method of obtaining the current in the power transistor and the primary branch of the transformer, and those skilled in the art can select a suitable circuit topology as needed.

[0151] In a specific embodiment, the method for determining the operating mode of the AC / DC power converter based on the second signal includes:

[0152] If the voltage represented by the second signal is less than a second threshold voltage, determining that the operating mode of the AC / DC power converter is a sleep mode;

[0153] If the voltage represented by the second signal is greater than or equal to a second threshold voltage, it is determined that the operating mode of the AC / DC power converter is a normal operating mode.

[0154] In this case, the method for determining the power supply mode of the primary-side control chip 10 based on the first signal and the second signal includes:

[0155] determining an operating mode of the AC / DC power converter based on the second signal, the operating mode including a normal operating mode and a sleep mode;

[0156] The power supply mode of the primary side control chip 10 is determined based on the working mode and the first signal, wherein:

[0157] When the operating mode is the normal operating mode, if the voltage represented by the first signal is greater than or equal to a first lower threshold voltage and less than or equal to a first upper threshold voltage, it is determined that the power supply mode of the primary control chip 10 is the auxiliary winding power supply mode;

[0158] Specifically, if the voltage represented by the first signal is greater than or equal to a first lower threshold voltage and less than or equal to a first upper threshold voltage, it can be considered that the auxiliary winding Naux supply voltage VDD is in a normal state;

[0159] When the operating mode is the normal operating mode, if the voltage represented by the first signal is less than a first lower threshold voltage or greater than a first upper threshold voltage, it is determined that the power supply mode of the primary control chip 10 is the external power supply mode;

[0160] Specifically, if the voltage represented by the first signal is less than the first lower threshold voltage, or greater than the first upper threshold voltage, it can be considered that the power supply of the auxiliary winding Naux is in an off state or an overhigh state, corresponding to insufficient power supply of the auxiliary winding Naux, or a circuit failure.

[0161] When the working mode is the sleep mode, if the voltage represented by the first signal is less than the first lower threshold voltage, the power supply mode of the primary control chip 10 is determined to be the external power supply mode; otherwise, it is the auxiliary winding power supply mode.

[0162] Specifically, if the voltage represented by the first signal is less than a first lower threshold voltage, it can be considered that the auxiliary winding Naux is under-powered.

[0163] It can be seen that the present invention can determine the working status of the circuit through the power supply voltage sampling module 101 and the current sampling module 102, and switch to the auxiliary winding Naux power supply mode only when the auxiliary winding Naux is underpowered or a circuit failure occurs, thereby safely powering the primary side control chip 10.

[0164] exist Figure 5 In the example, the switching between the auxiliary winding Naux power supply mode and the external power supply mode can also be understood as the power transistor Q1 being set to stop working in the external power supply mode.

[0165] In actual work, the situation where the above circuit fails also includes a failure in the output of the secondary circuit 2 .

[0166] In this case, one implementation method is to refer to Figure 9 , the primary side control chip 10 further includes a feedback terminal FB, the feedback terminal FB is used to obtain the output voltage DC_OUT of the secondary side circuit 2;

[0167] The overall control unit 1032 is further configured to determine a power supply mode of the primary control chip 10 based on the output voltage DC_OUT of the secondary circuit 2 , including:

[0168] When the operating mode is the normal operating mode, if the voltage DC_OUT output by the secondary circuit 2 is less than a fourth lower threshold voltage or greater than a fourth upper threshold voltage, it is determined that the power supply mode of the primary control chip 10 is the external power supply mode;

[0169] When the working mode is the sleep mode, if the voltage DC_OUT output by the secondary circuit 2 is less than a fourth lower threshold voltage, it is determined that the power supply mode of the primary control chip 10 is the external power supply mode.

[0170] Among them, the voltage DC_OUT output by the secondary circuit 2 is less than the fourth lower threshold voltage, which can be understood as the voltage DC_OUT output by the secondary circuit 2 is too low, and the voltage DC_OUT output by the secondary circuit 2 is greater than the fourth upper threshold voltage, which can be understood as the voltage DC_OUT output by the secondary circuit 2 is too high.

[0171] Please continue to refer to Figure 10 In one embodiment, the gate output terminal GATE of the main control unit 1032 is coupled to the control terminal of the power transistor Q1 to output a gate drive signal GATE to the control terminal of the power transistor Q1, wherein the gate drive signal GATE includes a first drive signal and a second drive signal;

[0172] The overall control unit 1032 is further configured to:

[0173] When the working mode is the sleep mode, if the voltage DC_OUT output by the secondary circuit 2 is less than the fifth threshold voltage, a first drive signal is output to the control end of the power transistor Q1 to transfer electric energy to the secondary circuit 2; otherwise, a second drive signal is output to the control end of the power transistor Q1 to control the power transistor Q1 to be disconnected.

[0174] Therefore, the present invention also ensures that in the sleep mode, the output voltage DC_OUT of the secondary circuit 2 will not be restarted due to power failure.

[0175] In one implementation, the fifth threshold voltage may be equal to the fourth lower threshold voltage.

[0176] In this case, a specific implementation method is shown in Figure 11 , shows an internal structure diagram of a primary side control chip 10, wherein:

[0177] The high-voltage power supply sampling unit 1031 includes a first comparator, a first input terminal of the first comparator is coupled to the high-voltage power terminal HV, a second input terminal thereof receives the third threshold voltage HV_enbHV_enb, and an output terminal thereof outputs the third signal;

[0178] The current sampling module 102 includes a second comparator, wherein a first input terminal of the second comparator is coupled to the current sampling terminal CS, a second input terminal thereof receives the second threshold voltage V_BCM, and an output terminal thereof outputs the second signal;

[0179] The supply voltage sampling module 101 includes a third comparator, wherein a first input terminal of the third comparator is coupled to the supply terminal VDD, a second input terminal of the third comparator receives the first lower threshold voltage VDD_ref1, a third input terminal of the third comparator receives the first upper threshold voltage VDD_ref2, and an output terminal of the third comparator outputs the first signal;

[0180] The output voltage sampling unit 104 includes a fourth comparator, wherein a first input terminal of the fourth comparator is coupled to the feedback terminal FB, a second input terminal of the fourth comparator receives the fourth lower threshold voltage VO_ref1, a third input terminal of the fourth upper threshold voltage VO_ref2, and an output terminal of the fourth comparator outputs the fifth signal;

[0181] The four input terminals of the overall control unit 1032 receive the first signal, the second signal, the third signal, and the fifth signal respectively, and the output terminal thereof outputs the fourth signal.

[0182] exist Figure 11 In the example of FIG, the overall control unit 1032 determines whether to start or stop external charging based on the first signal, the second signal, the third signal, and the fifth signal.

[0183] Specifically, if the voltage represented by the second signal is less than the second threshold voltage V_BCM, it is determined that the operating mode of the AC / DC power converter is the sleep mode; in this case, the external charging is determined to be turned on only when the voltage represented by the first signal is less than the first lower threshold voltage VDD_ref1, the voltage represented by the third signal is less than the third threshold voltage HV_enb, and the voltage represented by the fifth signal is less than the fourth lower threshold voltage VO_ref1.

[0184] If the voltage represented by the second signal is greater than or equal to the second threshold voltage V_BCM, it is determined that the operating mode of the AC / DC power converter is the normal operating mode; in this case, if the voltage represented by the first signal is less than the first lower threshold voltage VDD_ref1, the voltage represented by the first signal is greater than the first upper threshold voltage VDD_ref2, the voltage represented by the fifth signal is less than the fourth lower threshold voltage VO_ref1, or the voltage represented by the fifth signal is greater than the fourth upper threshold voltage VO_ref2, the external power supply mode is determined, and the power transistor Q1 is controlled to be disconnected;

[0185] On this basis, it is determined that the external charging is turned on when the voltage represented by the first signal is less than the first lower threshold voltage VDD_ref1 and the voltage represented by the third signal is less than the third threshold voltage HV_enb.

[0186] It can be seen that when the system is operating in zero-watt standby, the present invention ensures that the secondary side output voltage DC_OUT and the primary side control chip 10 will not restart due to power failure, and can also safely power the primary side control chip 10 when the auxiliary winding Naux is underpowered or a circuit fault occurs.

[0187] In addition, an embodiment of the present invention further provides an electronic device including any of the chip power supply systems described above. For example, the electronic device may be a charger, etc. It should be understood that the present invention is not limited to this, and any electronic device that requires powering a primary chip falls within the scope of protection of the present invention.

[0188] In summary, the present invention sets the high-voltage power supply end of the primary control chip to be coupled to the primary voltage input end through the power supply module, and its power supply end is coupled to the first end of the power supply capacitor, the first end of the power supply capacitor is also coupled to the first end of the auxiliary winding through the rectifier diode, the second end of the power supply capacitor is coupled to the second end of the auxiliary winding, and the second end of the power supply capacitor is also grounded. The primary control chip is configured to determine the power supply mode of the primary control chip based on the voltage value of the power supply end of the primary control chip and the current of the power transistor flowing through the primary circuit, and then determine whether to turn on external charging based on the voltage value of the high-voltage power supply end. Only when external charging is turned on, the power supply module is connected and the power supply capacitor is charged using the high-voltage power supply end. Therefore, the present invention can safely power the primary control chip when the auxiliary winding is underpowered or a circuit failure occurs.

[0189] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the scope defined by the claims.

Claims

1. A chip power supply system, applied to a primary-side control chip of an AC / DC power converter, wherein the AC / DC power converter comprises a primary circuit, a transformer, and a secondary circuit coupled in sequence, wherein the transformer comprises a primary winding, an auxiliary winding, and a secondary winding, and the primary circuit comprises a rectifier module, an RCD module, the power transistor, and a sampling resistor; a first end of the primary winding is coupled to a primary voltage input terminal via the rectifier module, a second end of the primary winding is coupled to ground via a power transistor and a sampling resistor, and a second end of the primary winding is further coupled to the first end of the primary winding via the RCD module; characterized in that: The high-voltage power supply terminal of the primary control chip is coupled to the primary voltage input terminal through the power supply module, and its power supply terminal is coupled to the first terminal of the power supply capacitor. The first terminal of the power supply capacitor is also coupled to the first terminal of the auxiliary winding through a rectifier diode. The second terminal of the power supply capacitor is coupled to the second terminal of the auxiliary winding. The second terminal of the power supply capacitor is also grounded. The current sampling terminal of the primary control chip is coupled to the first terminal of the sampling resistor; wherein: The primary side control chip includes: a power supply voltage sampling module, coupled to the power supply terminal, for acquiring the voltage value of the power supply terminal of the primary side control chip in real time and outputting a first signal; a current sampling module, coupled to the current sampling terminal, configured to obtain a current flowing through the power transistor of the primary circuit and output a second signal; High-voltage power supply module, including: a high-voltage power supply sampling unit, coupled to the high-voltage power terminal, for acquiring a voltage value of the high-voltage power terminal in real time and outputting a third signal; a main control unit, configured to determine a power supply mode of the primary control chip based at least on the first signal and the second signal, and to determine whether to start or stop external charging based on the first signal, the power supply mode, and the third signal, and output a fourth signal, wherein the power supply mode includes an auxiliary winding power supply mode and an external power supply mode; The high-voltage power supply unit is coupled to the power supply end and the high-voltage power supply end respectively, and its control end receives the fourth signal, and is used to connect the power supply module when the fourth signal indicates that external charging is turned on, and use the high-voltage power supply end to charge the power supply capacitor.

2. The chip power supply system according to claim 1, wherein: The method for determining whether to start or stop external charging based on the first signal, the power supply mode, and the third signal includes: When the power supply mode is the auxiliary winding power supply mode, stopping external charging; When the power supply mode is the external power supply mode, starting and stopping the external charging are determined based on the voltage represented by the first signal and the third signal, wherein: If the voltage represented by the first signal is less than a first lower threshold voltage, and the voltage represented by the third signal is less than a third threshold voltage, external charging is started; otherwise, external charging is stopped.

3. The chip power supply system according to claim 1, wherein: The method for determining a power supply mode of the primary-side control chip based on the first signal and the second signal includes: determining an operating mode of the AC / DC power converter based on the second signal, the operating mode including a normal operating mode and a sleep mode; The power supply mode of the primary control chip is determined based on the operating mode and the first signal, wherein: When the operating mode is the normal operating mode, if the voltage represented by the first signal is greater than or equal to a first lower threshold voltage and less than or equal to a first upper threshold voltage, determining that the power supply mode of the primary control chip is the auxiliary winding power supply mode; When the operating mode is the normal operating mode, if the voltage represented by the first signal is less than a first lower threshold voltage or greater than a first upper threshold voltage, determining that the power supply mode of the primary control chip is the external power supply mode; When the working mode is the sleep mode, if the voltage represented by the first signal is less than a first lower threshold voltage, the power supply mode of the primary control chip is determined to be the external power supply mode; otherwise, it is the auxiliary winding power supply mode.

4. The chip power supply system according to claim 3, wherein: The method for determining an operating mode of the AC / DC power converter based on the second signal includes: If the voltage represented by the second signal is less than a second threshold voltage, determining that the operating mode of the AC / DC power converter is a sleep mode; If the voltage represented by the second signal is greater than or equal to a second threshold voltage, it is determined that the operating mode of the AC / DC power converter is a normal operating mode.

5. The chip power supply system according to claim 3, wherein: The primary side control chip further includes a feedback terminal, and the feedback terminal is used to obtain the output voltage of the secondary side circuit; The overall control unit is further configured to determine a power supply mode of the primary-side control chip based on the output voltage of the secondary-side circuit, including: When the operating mode is the normal operating mode, if the voltage output by the secondary circuit is less than a fourth lower threshold voltage or greater than a fourth upper threshold voltage, determining that the power supply mode of the primary control chip is the external power supply mode; When the working mode is the sleep mode, if the voltage output by the secondary circuit is less than a fourth lower threshold voltage, it is determined that the power supply mode of the primary control chip is the external power supply mode.

6. The chip power supply system according to claim 5, wherein: The output terminal of the main control unit is coupled to the control terminal of the power transistor to output a gate driving signal to the control terminal of the power transistor, wherein the gate driving signal includes a first driving signal and a second driving signal; The main control unit is also used to: When the working mode is the sleep mode, if the voltage output by the secondary circuit is less than a fifth threshold voltage, outputting a first driving signal to the control terminal of the power transistor to transfer electric energy to the secondary circuit; Otherwise, a second driving signal is output to the control terminal of the power transistor to control the power transistor to be turned off.

7. The chip power supply system according to claim 5, wherein: The secondary circuit includes an output capacitor and a synchronous rectifier MOS tube, and the power converter also includes an optocoupler unit: The first end of the secondary winding is coupled to the first end of the output capacitor through the synchronous rectifier MOS transistor, the second end of the output capacitor is grounded, and the output capacitor supplies power to the connected load; The first end of the optical coupling unit is coupled to the first end of the output capacitor, and the second end of the optical coupling unit is coupled to the feedback end of the primary side control chip; The optical coupling unit is configured to obtain and feed back to the primary-side control chip the voltage output by the secondary-side circuit.

8. The chip power supply system according to claim 1, wherein: The power taking module includes a clamping unit, a power taking resistor and a filter capacitor; The first input terminal and the second input terminal of the clamping unit are respectively coupled to the first primary voltage input terminal and the second primary voltage input terminal, and the output terminal thereof is coupled to the high-voltage power supply terminal of the primary control chip through the power supply resistor, and the high-voltage power supply terminal is grounded through the filter capacitor.

9. The chip power supply system according to claim 6, wherein: The clamping unit includes a forward clamping diode and a negative clamping diode; The positive electrode of the forward clamping diode is coupled to the first primary voltage input terminal, the positive electrode of the negative clamping diode is coupled to the second primary voltage input terminal, the negative electrode of the forward clamping diode and the negative electrode of the negative clamping diode are coupled through a first node, and the first node is also coupled to the high-voltage power supply terminal of the primary control chip through the power supply resistor.

10. The chip power supply system according to claim 1, wherein: The high-voltage power supply unit includes a pull-down constant current source; The first end of the pull-down constant current source is coupled to the high-voltage power supply end, the second end thereof is coupled to the power supply end, and the control end thereof is used to receive the fourth signal, wherein, when the fourth signal indicates that external charging is turned on, the pull-down constant current source outputs a constant current to connect the power supply module.

11. The chip power supply system according to claim 1, wherein: The chip power supply system further includes a first voltage-dividing resistor and a second voltage-dividing resistor; The first end of the first voltage-dividing resistor and the first end of the second voltage-dividing resistor are both coupled to the power supply voltage sampling module, the second end of the first voltage-dividing resistor is coupled to the first end of the power supply capacitor, and the second end of the second voltage-dividing resistor is grounded.

12. An electronic device, characterized in that: The chip power supply system comprises the chip power supply system according to any one of claims 1 to 11.

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