Power supply circuit and switching power supply conversion circuit

Abstract

The application relates to a power supply circuit and a switching power supply conversion circuit. A first control module outputs a starting signal to a current source module to make the current source module start a charging mode of an energy storage module to generate a power supply voltage at a power supply end when a power supply voltage meets a first preset condition. A second control module outputs a first control signal to make a current adjusting module control the current source module to output a first charging current to perform safe mode charging on the energy storage module when the power supply voltage meets the second preset condition and the first preset condition simultaneously. The second control module outputs a second control signal to make the current adjusting module control the current source module to output a second charging current to perform fast charging mode charging on the energy storage module when the power supply voltage VCC meets the third preset condition and the first preset condition simultaneously. Therefore, the power supply circuit can realize large-current fast charging, effectively protect the circuit when overload occurs, and improve the charging efficiency, charging safety and service life of the power supply circuit.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of switching power supply, in particular to a power supply circuit and a switching power supply conversion circuit. BACKGROUND

[0002] High-voltage power supply integrated circuits, usually need a low-voltage power supply VCC power supply circuit, the low-voltage power supply VCC as the working voltage of integrated circuit, to the integrated circuit internal low-voltage circuit power supply. Integrated circuit VCC pin usually need to be decoupling capacitor. In the application, when the low-voltage power supply VCC does not reach the expected working voltage value, on the one hand, the large charging current is needed to charge the decoupling capacitor, so that VCC quickly reaches the expected working voltage value, so that the integrated circuit can work normally; on the other hand, if VCC overload, excessive charging current will affect the efficiency, and even because of power consumption limit, cause integrated circuit damage.

[0003] Therefore, the existing low-voltage power supply VCC power supply circuit, when charging the decoupling capacitor, there is VCC overload leading to excessive charging current, thereby reducing the power supply efficiency, low safety problem. SUMMARY

[0004] The embodiment of the present application provides a power supply circuit and a switching power supply conversion circuit, which has high charging efficiency and can safely supply power.

[0005] In order to achieve the purpose of the present application, the present application adopts the following technical scheme:

[0006] A power supply circuit, comprising a power supply end, further comprising:

[0007] A current source module is used for connecting with an external power supply, and starting the charging mode of an energy storage module to generate a power supply voltage at the power supply end when receiving a start signal;

[0008] A first control module is connected with the current source module and the power supply end respectively, and is used for outputting the start signal to the current source module when the power supply voltage meets a first preset condition;

[0009] A second control module is connected with the power supply end, and is used for outputting a first control signal when the power supply voltage meets a second preset condition and the first preset condition, and outputting a second control signal when the power supply voltage meets a third preset condition and the first preset condition;

[0010] A current regulation module is connected with the power supply end, the second control module and the current source module, respectively, for controlling the current source module to output a first charging current for safe mode charging of the energy storage module when the first control signal is received, and for controlling the current source module to output a second charging current for fast charging mode charging of the energy storage module when the second control signal is received, wherein the first charging current is less than the second charging current.

[0011] In one of the embodiments, the first preset condition is that the power supply voltage is less than a first threshold voltage, the second preset condition is that the power supply voltage is less than a second threshold voltage, and the third preset condition is that the power supply voltage is greater than the second threshold voltage.

[0012] In one of the embodiments, the second threshold voltage is less than the first threshold voltage.

[0013] In one of the embodiments, the current source module comprises:

[0014] A first switch unit comprises a first input end, a first output end and a first controlled end, the first controlled end is connected with the first control module, the first output end is grounded, and the first switch unit is used for disconnecting the path between the first input end and the first output end when the start signal is received.

[0015] A current source unit is connected with the first input end, and is used for connecting with the external power supply, and is used for starting the charging mode when the first switch unit disconnects the path between the first input end and the first output end, and is used for outputting the first charging current when the charging mode and the first bias voltage are received, and is used for outputting the second charging current when the charging mode and the second bias voltage are received.

[0016] In one of the embodiments, the current source unit comprises:

[0017] A field effect transistor, the drain of the field effect transistor is connected with the external power supply, the source of the field effect transistor is connected with the current regulation module, and the gate of the field effect transistor is connected with the first input end of the first switch unit.

[0018] In one of the embodiments, the switch unit comprises:

[0019] A first MOS transistor, the gate of the first MOS transistor is the first controlled end, the drain of the first MOS transistor is the first input end, and the source of the first MOS transistor is the first output end.

[0020] In one of the embodiments, the current regulation module comprises:

[0021] a second switch unit comprising a second input end, a second output end and a second controlled end, the second controlled end being connected with the second control module, the second output end being grounded, the second switch unit being configured to turn on a path between the second input end and the second output end when receiving the first control signal, and turn off the path between the second input end and the second output end when receiving the second control signal;

[0022] a voltage control unit connected with the second switch unit, the current source module and the energy storage module, respectively, configured to output the first bias voltage when the second switch unit turns on the path between the second input end and the second output end, output the second bias voltage when the second switch unit turns off the path between the second input end and the second output end, and output the first charging current to the energy storage module when receiving the first charging current, and output the second charging current to the energy storage module when receiving the second charging current.

[0023] In one of the embodiments, the second switch unit comprises:

[0024] a second MOS transistor, a gate of the second MOS transistor being the second controlled end, a drain of the second MOS transistor being the second input end, and a source of the second MOS transistor being the second output end.

[0025] In one of the embodiments, the voltage control unit comprises:

[0026] a first resistor, a second resistor, a third MOS transistor, a fourth MOS transistor, a first triode, a second triode and a diode, wherein a first end of the first resistor and a drain of the third MOS transistor are connected in common and connected with the current source module, a second end of the first resistor, an emitter of the first triode and an emitter of the second triode are connected in common and connected with the current source module, a source of the third MOS transistor, a first end of the second resistor and the second input end are connected in common, a second end of the second resistor is grounded, a gate of the third MOS transistor, a gate of the fourth MOS transistor, a drain of the fourth MOS transistor and a collector of the first triode are connected in common, a base of the second triode, a collector of the second triode and a positive electrode of the diode are connected in common, and a negative electrode of the diode is connected in common with the energy storage module at the power supply end.

[0027] In one of the embodiments, the first control module comprises:

[0028] a first comparator, a positive phase input end of the first comparator being connected with the power supply end, a negative phase input end being connected with a first threshold voltage, and an output end of the first comparator being connected with the current source module.

[0029] The second control module comprises:

[0030] a second comparator, a positive input terminal of the second comparator being connected to the second threshold voltage, a negative input terminal of the second comparator being connected to the power supply terminal, and an output terminal of the second comparator being connected to the current regulation module.

[0031] In one of the embodiments, the first control module is further configured to output an off signal when the power supply voltage is greater than the first threshold voltage.

[0032] The current source module is further configured to stop charging the energy storage module when the off signal is received.

[0033] In one of the embodiments, the first control module is further configured to output the start signal to enable the current source module to charge the energy storage module when the current source module outputs the second charging current and when the power supply voltage drops to a hysteresis lower limit voltage, and output the off signal to disable the current source module to stop charging the energy storage module when the power supply voltage rises to a hysteresis upper limit voltage.

[0034] A switching power supply conversion circuit comprises:

[0035] The power supply circuit as described above.

[0036] The power supply circuit and the switching power supply conversion circuit comprise a power supply terminal, a current source module, a first control module, a second control module, and a current regulation module. The current source module is configured to be connected to an external power supply and start a charging mode of an energy storage module to generate a power supply voltage VCC at the power supply terminal when a start signal is received. The first control module is connected to the current source module and the power supply terminal, and configured to output the start signal to the current source module when the power supply voltage VCC meets a first preset condition. The second control module is connected to the power supply terminal, and configured to output a first control signal when the power supply voltage VCC meets a second preset condition and the first preset condition simultaneously, and output a second control signal when the power supply voltage VCC meets a third preset condition and the first preset condition simultaneously. The current regulation module is connected to the power supply terminal, the second control module, and the current source module, and configured to control the current source module to output a first charging current for safe mode charging of the energy storage module when the first control signal is received, and control the current source module to output a second charging current for fast charging mode charging of the energy storage module when the second control signal is received. Thus, the circuit modules of the power supply circuit are simple, and can realize large-current fast charging start, effectively protect the circuit in overcurrent and short circuit conditions, and improve the charging efficiency, charging safety, and service life of the power supply circuit. BRIEF DESCRIPTION OF DRAWINGS

[0037] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the accompanying drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced. Obviously, the accompanying drawings in the following description only represent some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor.

[0038] Figure 1 A structural block diagram of a power supply circuit in an embodiment;

[0039] Figure 2 A structural block diagram of a power supply circuit in an embodiment;

[0040] Figure 3 A circuit schematic diagram of a power supply circuit in an embodiment. DETAILED DESCRIPTION

[0041] In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the accompanying drawings. The preferred embodiments of the present application are shown in the accompanying drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the disclosure of the present application more thorough and comprehensive.

[0042] It can be understood that the terms "first", "second", and the like used in the present application can be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish the first element from another element, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise specifically limited.

[0043] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs. The terms used in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application.

[0044] Figure 1 A structural block diagram of a power supply circuit in an embodiment. As shown in Figure 1 The power supply circuit 10 includes a power supply end, and further includes a current source module 110, a first control module 120, a second control module 130, and a current adjusting module 140. The power supply end is used to be connected with an energy storage module 150.

[0045] In the embodiment, the current source module 110 is configured to be connected with an external power supply, and start the charging mode of the energy storage module 150 to generate the supply voltage VCC at the supply end when receiving a start signal.

[0046] The current source module 110 is configured to be connected with the external power supply, and output a charging current under the control of the first control module 120 and the current regulation module 140 to realize the charging function of the energy storage module 150. Specifically, the current source module 110 starts the charging mode of the energy storage module 150 to generate the supply voltage VCC at the supply end when receiving the start signal output by the first control module 120, and outputs the first charging current or the second charging current under the control of the current regulation module 140.

[0047] In some embodiments, the external power supply provides a DC bus voltage for the current source module 110, and the current source module 110 can be integrated with a field effect transistor, so that high voltage access can be realized.

[0048] In the embodiment, the first control module 120 is connected with the current source module 110 and the supply end, respectively, and is configured to output a start signal to the current source module 110 when the supply voltage VCC meets a first preset condition.

[0049] The first control module 120 is connected with the current source module 110, and is configured to control the charging state of the current source module 110. The start signal is used to control the current source module 110 to turn on the charging path between the external power supply and the energy storage module 150, so that the current source module 110 charges the energy storage module 150. The start signal can be an analog signal, for example, it can be a level signal. Specifically, the level signal can be set to a low level signal or a high level signal according to the internal specific devices of the first control module 120 and the current source module 110. For example, the first control module 120 outputs a low level when the supply voltage VCC meets the first preset condition.

[0050] In some embodiments, the first preset condition is that the supply voltage VCC is less than a first threshold voltage Vref1. The first control module 120 outputs the start signal when the supply voltage VCC is less than the first threshold voltage Vref1. The first threshold voltage Vref1 can be set according to the actual working voltage of the application product of the power supply circuit, for example, when the application product needs a working voltage of 5V, the first threshold voltage Vref1 can be set to 5V.

[0051] In some embodiments, the first control module 120 is further configured to output an off signal when the supply voltage VCC is greater than the first threshold voltage Vref1, so that the current source module 110 stops charging the energy storage module 150 when receiving the off signal. The off signal is similar to the start signal in signal type, i.e., when the start signal is a low signal, the off signal is a high signal, and when the start signal is a high signal, the off signal is a low signal. The specific signal type can be set according to the internal specific devices of the first control module 120 and the current source module 110.

[0052] In some embodiments, the first control module 120 is a hysteresis control module, and the hysteresis threshold includes a lower limit voltage VL (VL < Vref1, Vref1 is the first threshold voltage Vref1) and an upper limit voltage VH (VH > Vref1, Vref1 is the first threshold voltage Vref1). The first control module 120 is further configured to output a start signal to make the current source module 110 charge the energy storage module 150 when the current source module 110 outputs the second charging current and when the supply voltage VCC drops to the lower limit voltage VL, and output an off signal to make the current source module 110 stop charging the energy storage module 150 when the supply voltage VCC rises to the upper limit voltage VH.

[0053] When the current source module 110 charges the energy storage module 150 with the second charging current, the supply circuit is in a fast charging state, and the overload situation can be excluded. The first control module 120 limits the supply voltage VCC within the hysteresis range centered on the first threshold voltage Vref1. When the supply voltage VCC drops to the lower limit voltage VL at a certain time, the start signal is output to make the current source module 110 charge the energy storage module 150. When the supply voltage VCC rises to the upper limit voltage VH at a certain time, the off signal is output to make the current source module 110 stop charging the energy storage module 150. This state will be maintained until the output voltage drops to the lower limit of the hysteresis again, and then the next charging period begins. Since the hysteresis control process has no delay link, it has a very fast transient response speed, so that the supply circuit can be in a fast charging mode of maintaining the second current value state of the supply voltage VCC within the hysteresis range centered on the first threshold voltage Vref1, thereby improving the charging efficiency.

[0054] In some embodiments, the first control module 120 can include a comparator or a combination of devices with voltage comparison function. Taking the case that the first control module 120 includes a first comparator, the non-inverting input terminal of the first comparator is connected to the power supply terminal, the inverting input terminal is connected to the first threshold voltage Vref1, and the output terminal of the first comparator is connected to the current source module 110, so that the first comparator can compare the power supply voltage VCC input by the non-inverting input terminal with the first threshold voltage Vref1 input by the inverting input terminal, and output a low level when the power supply voltage VCC is less than the first threshold voltage Vref1, and output a high level when the power supply voltage VCC is greater than the first threshold voltage Vref1. Wherein, the first comparator can be a hysteresis comparator, so as to realize the hysteresis function at the same time.

[0055] In the embodiment, the second control module 130 is connected to the current adjustment module 140 and the power supply terminal, and is configured to output a first control signal when the power supply voltage VCC meets the second preset condition and the first preset condition at the same time, and output a second control signal when the power supply voltage VCC meets the third preset condition and the first preset condition at the same time.

[0056] Wherein, the second control module 130 is connected to the current adjustment module 140, and is configured to output a corresponding control signal according to the size of the power supply voltage VCC to trigger the current adjustment module 140 to control the current output by the current source module 110. Specifically, the first control signal is output when the power supply voltage VCC meets the second preset condition and the first preset condition at the same time, so as to trigger the current adjustment module 140 to control the current source module 110 to output the first charging current, so that the current source module 110 performs exploratory safe charging on the energy storage module 150; the second control signal is output when the power supply voltage VCC meets the third preset condition and the first preset condition at the same time, so as to trigger the current adjustment module 140 to control the current source module 110 to output the second charging current, so that the current source module 110 performs fast charging. Therefore, the second control module 130 can indirectly control the charging current of the current source module 110 according to the size of the power supply voltage VCC.

[0057] Wherein, the first control signal and the second control signal can be analog signals, for example, can be level signals. Specifically, the level signal can be set to a low level signal or a high level signal according to the actual circuit devices of the second control module 130 and the current adjustment module 140.

[0058] The second preset condition and the third preset condition correspond to different voltage value ranges, and different voltage value ranges can be used to infer different charging stages of the current source module 110. Different charging stages can be used to set different charging current values. The voltage value range corresponding to the initial power-on state and the overload potential state is usually small, and the voltage value range corresponding to the middle and late normal charging stage is usually large. Therefore, when it is detected that the supply voltage VCC is in the voltage value range of the initial power-on state and the overload potential state, the current source module 110 can be controlled to output a small charging current to achieve exploratory safe charging. When the supply voltage VCC is in the voltage value range of the middle and late normal charging stage, the current source module 110 can be controlled to output a large charging current to achieve fast charging and improve charging efficiency.

[0059] In some embodiments, the second preset condition is that the supply voltage VCC is less than the second threshold voltage Vref2, and the third preset condition is that the supply voltage VCC is greater than the second threshold voltage Vref2. The second threshold voltage Vref2 can be set according to the intermediate critical point voltage value between the voltage value range of the initial power-on state and the overload potential state and the voltage value range of the middle and late normal charging stage of the supply voltage VCC. When the supply voltage VCC is less than the intermediate critical point voltage value, it can be known that the current source module 110 can be in the initial power-on state or in the overload potential state and needs to be exploratory safe charging. When the supply voltage VCC is greater than the intermediate critical point voltage value, it can be known that the current source module 110 is in a safe charging state and can be in a fast charging mode. When the supply voltage VCC is less than the second threshold voltage Vref2, the first charging current is set for exploratory safe charging regardless of the state of the energy storage module 150. On the one hand, if the energy storage module 150 is only in the initial power-on state, slow charging in the start-up stage can be achieved. On the other hand, if the energy storage module 150 is in an overload state, charging with the first charging current will not exacerbate damage to the internal supply circuit.

[0060] Optionally, considering the safety and speed of power supply, the second threshold voltage Vref2 is usually set to several hundred millivolts. The specific value can be set according to the under-voltage protection threshold of the application product of the power supply circuit 10, for example, the second threshold voltage Vref2 is set to be lower than the under-voltage protection threshold of the application product.

[0061] In some embodiments, the second control module 130 can include a comparator or a combination of devices with voltage comparison function. Taking the case that the second control module 130 includes a second comparator, the negative phase input end of the second comparator is connected with the power supply end, the positive phase input end is connected with the second threshold voltage Vref2, and the output end of the second comparator is connected with the current regulation module 140, so that the second comparator can compare the second threshold voltage Vref2 input by the positive phase input end and the power supply voltage VCC input by the negative phase input end, output high level when the power supply voltage VCC is less than the second threshold voltage Vref2, and output low level when the power supply voltage VCC is greater than the second threshold voltage Vref2.

[0062] In the embodiment, the current regulation module 140 is connected with the power supply end, the second control module 130 and the current source module 110 respectively, and can be connected with the energy storage module 150 through the power supply end to output the charging current output by the current source module 110 to the energy storage module 150. The current regulation module 140 is used to control the current source module 110 to output the first charging current for safe mode charging to the energy storage module 150 when receiving the first control signal, and control the current source module 110 to output the second charging current for fast charging mode charging to the energy storage module 150 when receiving the second control signal, wherein the first charging current is less than the second charging current.

[0063] The first charging current is a safe charging current, which can be used for safe charging of the energy storage module 150 in the initial power-on state, and can also be used for safe charging in the overload state. The second charging current is greater than the first charging current, which can be used for fast charging.

[0064] In some embodiments, the second charging current and the first charging current can be set according to the actual circuit condition, and the maximum current of the power supply circuit devices that can still perform safe charging in the overload state of the energy storage module 150 can be set as the first charging current.

[0065] In some embodiments, the second charging current can be set as 10 times of the first charging current, for example, the first charging current is set in the level of several hundred uA, and the second current value is set in the level of several mA, so that the first charging current in the level of several hundred uA can be used for tentative safe charging, and the second current value in the level of several mA can be used for fast charging, thereby improving the charging efficiency of the circuit.

[0066] In some embodiments, on the basis of being capable of safe charging, the charging current can also be set according to the circuit environment to which the power supply circuit is applied. For example, the power supply circuit is applied to a switching power supply converter, and the switching power supply converter needs to supply power to an external circuit, so that the first charging current and the second charging current can be set according to the discharge current of the switching power supply converter, so that the charging current meets the demand of the discharge current, and the balance of the voltage of the switching power supply converter is maintained.

[0067] The power supply circuit 10 provided by the embodiment includes a power supply end, a current source module 110, a first control module 120, a second control module 130, and a current adjustment module 140. The current source module 110 is used to be connected with an external power supply, and to start the charging mode of an energy storage module to generate a power supply voltage VCC at the power supply end when a start signal is received. The first control module 120 is connected with the current source module 110 and the power supply end respectively, and is used to output the start signal to the current source module 110 when the power supply voltage VCC meets a first preset condition. The second control module 130 is connected with the power supply end, and is used to output a first control signal when the power supply voltage VCC meets a second preset condition and the first preset condition at the same time, and to output a second control signal when the power supply voltage VCC meets a third preset condition and the first preset condition at the same time. The current adjustment module 140 is connected with the power supply end, the second control module 130, and the current source module 110 respectively, and is used to control the current source module 110 to output a first charging current to charge the energy storage module 150 in a safe mode when the first control signal is received, and to control the current source module 110 to output a second charging current to charge the energy storage module 150 in a fast charging mode when the second control signal is received. Thus, the circuit modules of the power supply circuit are simple, and the power supply circuit can realize large-current fast charging start, and can effectively protect the circuit in the case of overcurrent and short circuit, and improve the charging efficiency, charging safety, and service life of the power supply circuit.

[0068] Referring to Figure 2 , Figure 2 is a circuit schematic diagram of the power supply circuit in an embodiment.

[0069] In the embodiment, the current source module 110 includes a first switching unit 1101 and a current source unit 1102.

[0070] The first switching unit 1101 includes a first input end, a first output end, and a first controlled end. The first controlled end is connected with the first control module 120, and the first output end is grounded (not shown in the figure). The first switching unit 1101 is used to disconnect the path between the first input end and the first output end when the start signal is received, so as to control the current source unit 1102 to start providing the charging current.

[0071] In other embodiments, the first switch unit 1101 is further configured to turn on the path between the first input end and the first output end when the turn-off signal is received, so as to control the current source unit 1102 to stop outputting the charging current.

[0072] The current source unit 1102 is connected with the first input end, and the current source unit 1102 is configured to be connected with an external power supply, and is configured to start the charging mode when the first switch unit 1101 turns off the path between the first input end and the first output end, and is configured to output the first charging current when the charging mode is started and the first bias voltage is received, and is configured to output the second charging current when the charging mode is started and the second bias voltage is received.

[0073] The bias voltage is used to control the charging current of the current source unit 1102, and different bias voltages enable the current source unit 1102 to output different charging currents according to different supply voltages VCC of the supply end in the charging mode to adapt to different charging states. The first bias voltage is smaller than the second bias voltage, and when the bias voltage is high, the current source unit 1102 can be controlled to output a larger charging current, and when the bias voltage is low, the current source unit 1102 can be controlled to output a smaller charging current, so that the current source unit 1102 can output the first charging current for exploratory safe charging and the second charging current for fast charging through the first bias voltage and the second bias voltage.

[0074] In this embodiment, the current adjusting module 140 includes a second switch unit 1401 and a voltage control unit 1402.

[0075] The second switch unit 1401 includes a second input end, a second output end and a second controlled end, the second controlled end is connected with the second control module 130, the second output end is grounded (not shown in the figure), and the second switch unit 1401 is configured to turn on the path between the second input end and the second output end when the first control signal is received, and is configured to turn off the path between the second input end and the second output end when the second control signal is received, so as to control the grounding of the voltage control unit 1402, and further control the voltage output of the voltage control unit 1402 to control the bias voltage of the current source unit 1102.

[0076] The voltage control unit 1402 is connected with the second switch unit 1401, the current source module 110 and the energy storage module 150 respectively, and is configured to output a first bias voltage when the second switch unit 1401 turns on the path between the second input end and the second output end, output a second bias voltage when the second switch unit 1401 turns off the path between the second input end and the second output end, and output the first charging current to the energy storage module 150 when the first charging current is received, and output the second charging current to the energy storage module 150 when the second charging current is received. The first bias voltage and the second bias voltage can make the current source unit 1102 output the first charging current for exploratory safe charging and output the second charging current for fast charging respectively.

[0077] Referring to Figure 3 , Figure 3 FIG. 1 is a circuit schematic diagram of a power supply circuit in an embodiment.

[0078] In the embodiment, the first switch unit 1101 includes:

[0079] The first MOS tube M1 has a first controlled end as a gate, a first input end as a drain and a first output end as a source.

[0080] In the embodiment, the current source unit 1102 includes:

[0081] The field effect tube JFET has a drain connected with an external power supply, a source connected with the current adjusting module 140 and a gate connected with the first input end of the first switch unit 1101. Optionally, a suitable depletion mode JFET is selected.

[0082] In the embodiment, the second switch unit 1401 includes:

[0083] The second MOS tube M2 has a second controlled end as a gate, a second input end as a drain and a second output end as a source.

[0084] In the embodiment, the voltage control unit 1402 includes:

[0085] The first resistor R1, the second resistor R2, the third MOS tube M3, the fourth MOS tube M4, the first triode Q1, the second triode Q2 and the diode D1, wherein the first end of the first resistor R1 and the drain of the third MOS tube M3 are connected and connected with the current source module 110, the second end of the first resistor R1, the emitter of the first triode Q1 and the emitter of the second triode Q2 are connected and connected with the current source module 110, the source of the third MOS tube M3, the first end of the second resistor R2 and the second input end are connected, the second end of the second resistor R2 is grounded, the gate of the third MOS tube M3, the gate of the fourth MOS tube M4, the drain of the fourth MOS tube M4 and the collector of the first triode Q1 are connected, the base of the second triode Q2, the collector of the second triode Q2 and the positive electrode of the diode D1 are connected, and the negative electrode of the diode D1 is connected with the energy storage module 150 at the power supply end.

[0086] In the embodiment, the first control module 120 comprises:

[0087] The first comparator A1 is connected with the power supply end at the positive input end, and the negative input end is connected with the first threshold voltage Vref1, and the output end of the first comparator A1 is connected with the current source module 110.

[0088] In the embodiment, the second control module 130 comprises:

[0089] The second comparator A2 is connected with the second threshold voltage Vref2 at the positive input end, and the negative input end is connected with the power supply end, and the output end of the second comparator A2 is connected with the current adjusting module 140.

[0090] In the embodiment, the energy storage module 150 comprises a capacitor C.

[0091] The principle of the power supply circuit in the embodiment is described as follows:

[0092] When the first comparator A1 detects that the power supply voltage VCC is higher than the first threshold voltage Vref1, a high level signal is output to control the first MOS tube M1 to be turned on, the gate of the field effect tube JFET is grounded, and the source of the field effect tube JFET is connected to the power supply end through the second triode Q2 and the diode D1, so that the source voltage of the field effect tube JFET is higher than the power supply voltage VCC. Selecting a suitable depletion mode JFET, so that the negative bias voltage is less than the gate threshold voltage of the field effect tube JFET, so that the JFET is turned off and the charging is stopped.

[0093] When the first comparator A1 detects that the supply voltage VCC is lower than the first threshold voltage Vref1, the first comparator A1 outputs a low level signal to control the first MOS transistor M1 to be off. At this time, the field effect transistor JFET starts to provide a charging current, and the size of the charging current is adjusted by the bias voltage between the gate and the source of the field effect transistor JFET. When the bias voltage is the first bias voltage, the field effect transistor JFET outputs a first charging current; when the bias voltage is the second bias voltage, the field effect transistor JFET outputs a second charging current.

[0094] The bias voltage between the gate and the source of the field effect transistor JFET is controlled by the second MOS transistor M2, the first resistor R1, the second resistor R2, the third MOS transistor M3, the fourth MOS transistor M4, the first triode Q1, the second triode Q2, and the diode D1. The charging current of the field effect transistor JFET is equal to the sum of the currents of the first triode Q1 and the second triode Q2. The current of the second triode Q2 is much larger than the current of the first triode Q1. The current of the first triode Q1 is conducted through the fourth MOS transistor M4, and the gate voltage of the third MOS transistor M3 is controlled by the source of the field effect transistor JFET through the first triode Q1 and the fourth MOS transistor M4.

[0095] Specifically, when the supply voltage VCC is lower than the second threshold voltage Vref2, the second comparator A2 outputs a high level, and the second MOS transistor M2 is turned on. The gate voltage of the field effect transistor JFET is determined by the first resistor R1, the on-resistance of the third MOS transistor M3, and the on-resistance of the second MOS transistor M2. The first resistor R1 is selected to be a relatively large resistance, so that the gate voltage of the field effect transistor JFET is close to ground level at this time, and the first bias voltage obtained is close to -Vref2. When the supply voltage VCC is higher than the second threshold voltage Vref2, the second comparator A2 outputs a low level, and the second MOS transistor M2 is turned off. The gate voltage of the field effect transistor JFET is determined by the first resistor R1, the on-resistance of the third MOS transistor M3, and the second resistor R2. R2 is selected to be a relatively large resistance. When the supply voltage VCC is close to the second threshold voltage Vref2, the second bias voltage generated between the gate and the source of the field effect transistor JFET at this time is close to -Vref2*(R1 / (R1+R2)). By selecting a suitable field effect transistor JFET, the field effect transistor JFET can output a first charging current of several hundred microamperes at the first bias voltage -Vref2 to achieve exploratory safe charging, and output a second charging current of several milliamperes at the second bias voltage -Vref2*(R1 / (R1+R2) to achieve fast charging. Thus, the power supply circuit 10 can achieve large current fast charging start, while in the case of overcurrent and short circuit, the circuit can be effectively protected, and the charging efficiency, charging safety, and service life of the power supply circuit are improved.

[0096] The embodiment also provides a switching power supply conversion circuit, which comprises the power supply circuit as described in the above embodiment, and the power supply circuit can be used to output a power supply voltage VCC at a power supply end to provide a working voltage for other internal module circuits of the switching power supply conversion circuit, so as to ensure the normal working of the switching power supply conversion circuit. The switching power supply conversion circuit can be an integrated switching power supply converter.

[0097] The switching power supply conversion circuit provided by the embodiment can achieve large-current fast charging starting, and can effectively and safely charge in the overcurrent and short-circuit conditions, so that the switching power supply conversion circuit has high charging efficiency, reliability and service life.

[0098] The above embodiment only expresses several implementation manners of the application, and the description is relatively specific and detailed, but it should not be understood as a limitation on the patent scope of the application. It should be pointed out that, for ordinary skilled persons in the art, several modifications and improvements can be made without departing from the concept of the application, and these all belong to the protection scope of the application. Therefore, the patent protection scope of the application should be subject to the appended claims.

Claims

1. A power supply circuit, comprising a power supply terminal, characterized in that, Also includes: A current source module is used to connect to an external power source and, upon receiving a start signal, activates the charging mode of the energy storage module to generate a supply voltage at the power supply terminal. The first control module is connected to the current source module and the power supply terminal respectively, and is used to output the start signal to the current source module when the power supply voltage meets the first preset condition; The second control module is connected to the power supply terminal and is used to output a first control signal when the power supply voltage simultaneously meets the second preset condition and the first preset condition, and to output a second control signal when the power supply voltage simultaneously meets the third preset condition and the first preset condition. A current regulation module is connected to the power supply terminal, the second control module, and the current source module respectively. It is used to control the current source module to output a first charging current to charge the energy storage module in safe mode when receiving the first control signal, and to control the current source module to output a second charging current to charge the energy storage module in fast charging mode when receiving the second control signal, wherein the first charging current is less than the second charging current. The current regulation module includes: The second switching unit includes a second input terminal, a second output terminal, and a second controlled terminal. The second controlled terminal is connected to the second control module, and the second output terminal is grounded. The second switching unit is used to turn on the path between the second input terminal and the second output terminal when receiving the first control signal, and to turn off the path between the second input terminal and the second output terminal when receiving the second control signal. The voltage control unit is connected to the second switching unit, the current source module, and the energy storage module respectively. It is used to output a first bias voltage when the second switching unit opens the path between the second input terminal and the second output terminal, and to output a second bias voltage when the second switching unit closes the path between the second input terminal and the second output terminal. It is also used to output the first charging current to the energy storage module when the first charging current is received, and to output the second charging current to the energy storage module when the second charging current is received.

2. The power supply circuit according to claim 1, characterized in that, The first preset condition is that the power supply voltage is less than a first threshold voltage; the second preset condition is that the power supply voltage is less than a second threshold voltage; and the third preset condition is that the power supply voltage is greater than the second threshold voltage. Wherein, the second threshold voltage is less than the first threshold voltage.

3. The power supply circuit according to claim 1 or 2, characterized in that, The current source module includes: The first switching unit includes a first input terminal, a first output terminal, and a first controlled terminal. The first controlled terminal is connected to the first control module, and the first output terminal is grounded. The first switching unit is used to disconnect the path between the first input terminal and the first output terminal when the start signal is received. A current source unit is connected to the first input terminal. The current source unit is used to connect to the external power supply and to enable the charging mode when the first switch unit disconnects the path between the first input terminal and the first output terminal. It is also used to output the first charging current when the charging mode is in operation and a first bias voltage is received, and to output a second charging current when the charging mode is in operation and a second bias voltage is received.

4. The power supply circuit according to claim 3, characterized in that, The current source unit includes: The field-effect transistor (FET) has its drain connected to the external power supply, its source connected to the current regulation module, and its gate connected to the first input terminal of the first switching unit.

5. The power supply circuit according to claim 3, characterized in that, The first switching unit includes: The first MOSFET has its gate as the first controlled terminal, its drain as the first input terminal, and its source as the first output terminal.

6. The power supply circuit according to claim 1, characterized in that, The second switching unit includes: The second MOSFET has its gate as the second controlled terminal, its drain as the second input terminal, and its source as the second output terminal.

7. The power supply circuit according to claim 1, characterized in that, The voltage control unit includes: The system comprises a first resistor, a second resistor, a third MOSFET, a fourth MOSFET, a first transistor, a second transistor, and a diode. The first terminal of the first resistor and the drain of the third MOSFET are connected together and connected to the current source module. The second terminal of the first resistor, the emitter of the first transistor, and the emitter of the second transistor are connected together and connected to the current source module. The source of the third MOSFET, the first terminal of the second resistor, and the second input terminal are connected together. The second terminal of the second resistor is grounded. The gate of the third MOSFET, the gate of the fourth MOSFET, the drain of the fourth MOSFET, and the collector of the first transistor are connected together. The base of the second transistor, the collector of the second transistor, and the anode of the diode are connected together. The cathode of the diode is connected to the power supply terminal along with the energy storage module.

8. The power supply circuit according to claim 1 or 2, characterized in that, The first control module includes: A first comparator, wherein the non-inverting input of the first comparator is connected to the power supply terminal, the inverting input of the first comparator is connected to a first threshold voltage, and the output of the first comparator is connected to the current source module; The second control module includes: The second comparator has a positive input terminal connected to a second threshold voltage, a negative input terminal connected to the power supply terminal, and an output terminal connected to the current regulation module.

9. The power supply circuit according to claim 2, characterized in that, The first control module is also configured to output a shutdown signal when the supply voltage is greater than the first threshold voltage; The current source module is also used to stop charging the energy storage module when the shutdown signal is received.

10. The power supply circuit according to claim 9, characterized in that, The first control module is further configured to output the start signal to charge the energy storage module when the current source module outputs the second charging current and the supply voltage drops to the hysteresis lower limit voltage, and to output the turn-off signal to stop the current source module from charging the energy storage module when the supply voltage rises to the hysteresis upper limit voltage.

11. A switching power supply conversion circuit, characterized in that, include: The power supply circuit as described in any one of claims 1-10.

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