Power supply system, self-powered control circuit, chip and method

Abstract

The application provides a power supply system, a self-powered control circuit, a chip and a method, which comprise: a first switch, one end of which is connected to the base of a triode, and the other end of which is connected to the output end of a driving module; a second switch, one end of which is connected to the emitter of the triode, and the other end of which is grounded; a third switch, one end of which is connected to the base of the triode, and the other end of which is grounded; a first diode, the positive electrode of which is connected to the emitter of the triode, and the negative electrode of which is connected to the input end of the driving module; and a control module, which controls the switching state of the first, second and third switches based on a current sampling signal and a working voltage, so that the maximum value of the current sampling signal approaches a preset value, and the working voltage approaches a preset voltage. The application adopts a double closed-loop control architecture of collector current adaptive control and working voltage stabilization, which not only ensures the stability of the working voltage, but also makes the triode collector current naturally drop to zero; the system impact is minimum, and the constant current precision of the constant current section of the system is high.

Description

Technical Field

[0001] This invention relates to the field of power supply design, and in particular to a power supply system, a self-powered control circuit, a chip, and a method. Background Technology

[0002] As competition in the cost-effectiveness of low-power ACDC chips and systems intensifies, the two-winding approach instead of the three-winding approach at the system level is becoming increasingly popular, and the chip-embedded BJT approach is also becoming mainstream in low-cost applications. The two-winding approach presents a challenge in chip power supply due to the lack of a power supply winding. Furthermore, BJTs, being minority carrier devices, suffer from minority carrier storage effects, preventing immediate turn-off and making the final turn-off point uncontrollable. The constant current accuracy of the constant current stage is directly related to the precision of the final turn-off point.

[0003] Therefore, how to ensure the safe shutdown of the BJT while maintaining the accuracy of the system's constant current under the premise of stable power supply to the chip has become one of the problems that urgently need to be solved by those skilled in the art. Summary of the Invention

[0004] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a power supply system, a self-powered control circuit, a chip, and a method to solve the problems of unstable power supply and poor constant current accuracy of the control chip in the two-winding power conversion system in the prior art.

[0005] To achieve the above and other related objectives, the present invention provides a self-powered control circuit, the self-powered control circuit comprising at least:

[0006] Transistor, first diode, first switch, second switch, third switch, driver module and control module;

[0007] One end of the first switch is connected to the base of the transistor, and the other end is connected to the output of the drive module;

[0008] One end of the second switch is connected to the emitter of the transistor, and the other end is grounded;

[0009] One end of the third switch is connected to the base of the transistor, and the other end is grounded;

[0010] The anode of the first diode is connected to the emitter of the transistor, and the cathode is connected to the input terminal of the drive module; the cathode of the first diode is connected to an energy storage capacitor outside the self-powered control circuit, and the energy storage capacitor is used to provide the operating voltage.

[0011] The control module is connected to the negative terminal of the first diode and receives a current sampling signal. Based on the current sampling signal and the operating voltage, it controls the switching states of the first switch, the second switch, and the third switch. The turn-off time of the first switch is adjusted by the current sampling signal so that the maximum value of the current sampling signal before the transistor turns off approaches a preset value. The turn-on time of the second switch is adjusted by the operating voltage so that the operating voltage approaches a preset voltage.

[0012] Optionally, the control module includes a reference signal generation unit, a comparison unit, a delay unit, a working voltage modulation unit, a first switch driving unit, a second switch driving unit, and a third switch driving unit;

[0013] The reference signal generation unit receives the current sampling signal, compares the current sampling signal with a preset value, and adjusts and generates a reference signal based on the comparison result; when the current sampling signal is greater than the preset value, the reference signal is decreased, and when the current sampling signal is less than the preset value, the reference signal is increased.

[0014] The comparison unit is connected to the output terminal of the reference signal generation unit and receives the current sampling signal, comparing the reference signal with the current sampling signal;

[0015] The first switch driving unit is connected to the output terminal of the comparison unit, and turns off the first switch when the current sampling signal is less than the reference signal;

[0016] The delay unit is connected to the output of the comparison unit and delays the comparison result for a set time, wherein the set time is proportional to the preset value.

[0017] The third switch driving unit is connected to the output terminal of the delay unit, and turns on the third switch after the first switch is turned off for a set time.

[0018] The working voltage modulation unit is connected to the working voltage and generates a turn-off signal for the second switch based on the difference between the working voltage and the preset voltage.

[0019] The second switch driving unit is connected to the output terminal of the delay unit and the working voltage modulation unit. When the third switch is turned on, the second switch is turned on, and the second switch is turned off based on the output signal of the working voltage modulation unit.

[0020] Optionally, the control module includes a reference signal generation unit, a comparison unit, a delay unit, a working voltage modulation unit, a first switch driving unit, a second switch driving unit, and a third switch driving unit;

[0021] The reference signal generation unit receives the current sampling signal, compares the current sampling signal with a preset value, and adjusts and generates a reference signal based on the comparison result; when the current sampling signal is greater than the preset value, the reference signal is decreased, and when the current sampling signal is less than the preset value, the reference signal is increased.

[0022] The comparison unit is connected to the output terminal of the reference signal generation unit and receives the current sampling signal, comparing the reference signal with the current sampling signal;

[0023] The first switch driving unit is connected to the output terminal of the comparison unit, and turns off the first switch when the current sampling signal is less than the reference signal;

[0024] The delay unit is connected to the output of the comparison unit and delays the comparison result for a set time, wherein the set time is proportional to the preset value.

[0025] The third switch driving unit is connected to the output terminal of the delay unit, and the third switch is turned on after the first switch turns off the delay time;

[0026] The working voltage modulation unit is connected to the working voltage and generates a conduction signal for the second switch based on the difference between the working voltage and the preset voltage;

[0027] The second switch driving unit is connected to the output terminal of the comparison unit and the working voltage modulation unit. When the first switch is turned off, the second switch is turned off, and the second switch is turned on based on the output signal of the working voltage modulation unit.

[0028] Alternatively, the reference signal generation unit includes a comparator and a logic subunit; the input of the comparator is connected to the preset value and the current sampling signal, and the preset value is compared with the current sampling signal; the logic subunit generates an initial value of the reference signal in an initial state, and then adjusts the reference signal based on the output signal of the comparator; wherein, the initial value of the reference signal is the product of the preset value and a coefficient less than 1.

[0029] To achieve the above and other related objectives, the present invention provides a self-powered control chip, the self-powered control chip comprising at least:

[0030] The self-powered control circuit described above includes a collector pin connected to the collector of the transistor, a working voltage pin connected to the negative terminal of the first diode, a grounding pin connected to the ground terminals of the second and third switches, and a current sampling pin connected to the current sampling signal.

[0031] To achieve the above and other related objectives, the present invention provides a power supply system, the power supply system comprising at least:

[0032] The switching power supply circuit and the aforementioned self-powered control circuit, wherein the self-powered control circuit controls the switching power supply circuit to perform power conversion; wherein the switching power supply circuit has a two-winding topology.

[0033] To achieve the above and other related objectives, the present invention provides a self-powered control method, wherein the self-powered control chip includes at least:

[0034] The second switch and the first switch are turned on, the third switch is turned off, and the transistor is turned on.

[0035] When the current sampling signal increases to the reference signal, the first switch is turned off; and the conduction time of the second switch is controlled based on the difference between the operating voltage and the preset voltage; when the first switch, the second switch and the third switch are turned off, the transistor remains in the conducting state based on the tailing effect;

[0036] After the first switch is turned off for a set time, the third switch is turned on, and the transistor is completely turned off.

[0037] Specifically, the reference signal is adjusted based on the comparison result between the current sampling signal and the preset value. If the maximum value of the current sampling signal before the transistor is turned off in the current cycle is greater than the preset value, the reference signal is decreased in the next cycle. If the maximum value of the current sampling signal before the transistor is turned off in the current cycle is less than the preset value, the reference signal is increased in the next cycle.

[0038] Optionally, the preset value is calculated based on a constant current algorithm.

[0039] Optionally, the adjustment amount of the reference signal is a fixed step size; or the adjustment amount of the reference signal is proportional to the difference between the current sampling signal and the preset value.

[0040] Alternatively, the turn-off time of the second switch can be determined based on the difference between the operating voltage and the preset voltage.

[0041] Alternatively, the second switch may be turned on simultaneously with the third switch.

[0042] Alternatively, the conduction time of the second switch can be determined based on the difference between the operating voltage and the preset voltage.

[0043] Alternatively, the second switch may be turned off at the same time as the first switch is turned off.

[0044] As described above, the power supply system, self-powered control circuit, chip, and method of the present invention have the following beneficial effects:

[0045] The power supply system, self-powered control circuit, chip, and method of the present invention adopt a dual closed-loop control architecture of collector current adaptive control to zero and VCC voltage regulation. This ensures the stability of the working voltage and allows the transistor collector current to naturally drop to zero, minimizing system impact. At the same time, it maintains the constant current sampling signal when the transistor collector current drops to zero, thereby ensuring the constant current accuracy of the system in the constant current section. Attached Figure Description

[0046] Figure 1 The diagram shows a control circuit for a two-winding power conversion system.

[0047] Figure 2 The diagram shown is a structural schematic of the self-powered control circuit of the present invention.

[0048] Figure 3 The diagram shown is a structural schematic of the control module of the present invention.

[0049] Figure 4 This is a schematic diagram of another structure of the control module of the present invention.

[0050] Figure 5 The diagram shown is a structural schematic of the power supply system of the present invention.

[0051] Figure 6 The diagram shown illustrates the principle of the self-powered control method of the present invention.

[0052] Figure 7 This is a schematic diagram illustrating another principle of the self-powered control method of the present invention.

[0053] Component designation explanation

[0054] 1. Control Circuit

[0055] 11 Control and Drive Module

[0056] 2 Self-powered control circuit

[0057] 21 Driver Module

[0058] 22 Control Module

[0059] 221 Reference Signal Generation Unit

[0060] 221a comparator

[0061] 221b Logic Subunit

[0062] 222 Comparison Unit

[0063] 223 Delay Units

[0064] 224 Operating Voltage Modulation Unit

[0065] 225 First Switch Drive Unit

[0066] 226 Second Switch Drive Unit

[0067] 227 Third Switch Drive Unit

[0068] 3 Rectifier Detailed Implementation

[0069] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0070] Please see Figures 1 to 7 It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0071] like Figure 1As shown, this is a control circuit 1 suitable for a two-winding power conversion system. The control circuit 1 includes a transistor Q1 (BJT), a first switch K1, a second switch K2, a third switch K3, a first capacitor C1, a first resistor Rcs1, and a control and drive module 11. The emitter of transistor Q1 is grounded through the first switch K1, and the base is grounded through the third switch K3. One end of the first resistor Rcs1 is grounded, and the other end provides a current sampling signal. One end of the second switch is connected to the emitter of transistor Q1, and the other end is grounded through the first capacitor C1. The control and drive module 11 receives the current sampling signal and connects to the upper plate of the first capacitor C1 to generate a drive signal for transistor Q1 and control signals for each switch. When the first switch K1 is turned off, the emitter current of transistor Q1 cannot change abruptly due to the minority carrier storage effect. The emitter current will flow into the first capacitor C1 to charge the operating voltage VCC to replenish the drive energy consumed when transistor Q1 is turned on. When transistor Q1 needs to be pre-turned off, the first switch K1 is turned off, and the second switch K2 is turned on simultaneously. The remaining collector current of transistor Q1 will charge the operating voltage VCC through the second switch K2. Once the operating voltage VCC is charged to a certain value, the third switch K3 is turned on, completely turning off transistor Q1. Because the longer transistor Q1 is on, the more power VCC consumes, and the longer the second switch K2 needs to be on, the collector current of transistor Q1 can be approximately controlled by relying solely on the voltage regulation loop of VCC. However, since both the control of the operating voltage VCC and the control of the collector current of transistor Q1 are completed by the second switch K2, the two quantities are not independent, and the collector current of transistor Q1 is not exactly zero when the third switch K3 is finally turned on.

[0072] Adding a pre-shutdown switch to the base of the transistor can decouple the control of the operating voltage VCC from the control of the collector current of transistor Q1. However, the collector current of transistor Q1 still cannot be guaranteed to be exactly zero, causing a surge to the base of transistor Q1, damaging its reliability and affecting system lifespan. For these reasons, this invention provides a self-powered control circuit that, while decoupling the control of the operating voltage VCC from the control of the collector current of transistor Q1, ensures that the collector current of transistor Q1 is exactly zero.

[0073] Example 1

[0074] like Figure 2 As shown, this embodiment provides a self-powered control circuit 2, which includes:

[0075] Transistor Q1, first diode D, first switch SW1, second switch SW2, third switch SW3, drive module 21 and control module 22.

[0076] like Figure 2 As shown, one end of the first switch SW1 is connected to the base of the transistor Q1, and the other end is connected to the output of the drive module 21; it is used to provide a drive signal path for the transistor Q1.

[0077] like Figure 2 As shown, one end of the second switch SW2 is connected to the emitter of the transistor Q1, and the other end is grounded to GND; it is used to provide a path to ground for the transistor Q1.

[0078] like Figure 2 As shown, one end of the third switch SW3 is connected to the base of the transistor Q1, and the other end is grounded to GND; it is used to pull down the base of the transistor Q1 to turn off the transistor Q1.

[0079] like Figure 2 As shown, the anode of the first diode D is connected to the emitter of the transistor Q1, and the cathode is connected to the input terminal of the drive module 21; the cathode of the first diode D is connected to the energy storage capacitor C2 outside the self-powered control circuit 2, and the energy storage capacitor C2 is used to provide the working voltage VCC; the working voltage VCC provides additional power to the drive module 21, thereby avoiding the use of auxiliary windings, reducing external circuits, and saving system costs.

[0080] like Figure 2 As shown, the control module 22 is connected to the negative terminal of the first diode D and receives a current sampling signal Vcs. Based on the current sampling signal Vcs and the operating voltage VCC, it controls the switching states of the first switch SW1, the second switch SW2, and the third switch SW3. The turn-off time of the first switch SW1 is adjusted by the current sampling signal Vcs so that the maximum value of the current sampling signal Vcs before the transistor Q1 is turned off approaches a preset value Vcs_final. The conduction time of the second switch SW2 is adjusted by the operating voltage VCC so that the operating voltage VCC approaches a preset voltage VCC_ref.

[0081] It should be noted that the current sampling signal Vcs is obtained through the sampling resistor Rcs2 outside the self-powered control circuit 2. The connection relationship between the sampling resistor Rcs and other devices is set according to the specific circuit design, and will not be described in detail here.

[0082] Specifically, such as Figure 3 As shown, in this embodiment, the control module 22 includes a reference signal generation unit 221, a comparison unit 222, a delay unit 223, a working voltage modulation unit 224, a first switch driving unit 225, a second switch driving unit 226, and a third switch driving unit 227.

[0083] More specifically, the reference signal generation unit 221 receives the current sampling signal Vcs, compares the current sampling signal Vcs with a preset value Vcs_final, and adjusts and generates a reference signal Vcs_pre based on the comparison result; when the current sampling signal Vcs is greater than the preset value Vcs_final, the reference signal Vcs_pre is decreased; when the current sampling signal Vcs is less than the preset value Vcs_final, the reference signal Vcs_pre is increased. Figure 3 As shown, as an example, the reference signal generation unit 221 includes a comparator 221a and a logic subunit 221b. The input of the comparator 221a is connected to the preset value Vcs_final and the current sampling signal Vcs, compares the preset value Vcs_final with the current sampling signal Vcs, and outputs the comparison result; wherein, the comparison result is only a high or low level indicating greater than or less than, or the comparison result is a difference with a signed bit. The logic subunit 221b is connected to the output of the comparator 221a. In the initial state, it generates an initial value for the reference signal Vcs_pre, which is the product of the preset value Vcs_final and a coefficient K less than 1. Then, it adjusts the reference signal Vcs_pre based on the output signal of the comparator 221a. The logic subunit 221b can adjust the reference signal Vcs_pre with a fixed step size based on the comparison result, or it can adjust the reference signal Vcs_pre with an adjustment amount proportional to the difference between the current sampling signal and the preset value based on the comparison result. As another example, the multiplier used to generate the initial value of the reference signal Vcs_pre is located outside the logic subunit 221b.

[0084] More specifically, the comparison unit 222 is connected to the output of the reference signal generation unit 221 and receives the current sampling signal Vcs, comparing the reference signal Vcs_pre with the current sampling signal Vcs. As an example, the non-inverting input of the comparison unit 222 is connected to the output of the reference signal generation unit 221, and the inverting input is connected to the current sampling signal Vcs. When the reference signal Vcs_pre is greater than the current sampling signal Vcs, it outputs a high level; when the reference signal Vcs_pre is less than the current sampling signal Vcs, it outputs a low level.

[0085] More specifically, the first switch driving unit 225 is connected to the output terminal of the comparison unit 222, and turns off the first switch SW1 when the current sampling signal Vcs is less than the reference signal Vcs_pre. As an example, the first switch SW1 is turned on when the level is high and turned off when the level is low.

[0086] More specifically, the delay unit 223 is connected to the output of the comparison unit 222, and delays the comparison result for a set time, which is proportional to the preset value Vcs_final. The preset value Vcs_final is a fixed value; therefore, the set time is also a fixed value.

[0087] More specifically, the third switch driving unit 227 is connected to the output terminal of the delay unit 223, and the third switch SW3 is turned on after the first switch 225 is turned off for a set time.

[0088] More specifically, the working voltage modulation unit 224 is connected to the working voltage VCC, generates a turn-off signal for the second switch SW2 based on the difference between the working voltage VCC and the preset voltage VCC_ref, and makes the working voltage VCC approach or equal to the preset voltage VCC_ref through a voltage regulator loop.

[0089] More specifically, the second switch driving unit 226 is connected to the output terminal of the delay unit 223 and the working voltage modulation unit 224. When the third switch SW3 is turned on, the second switch SW2 is turned on, and the second switch SW2 is turned off based on the output signal of the working voltage modulation unit 224. The second switch SW2 adopts trailing edge modulation.

[0090] It should be noted that the turn-on timing of the first switch SW1 and the turn-off timing of the third switch SW3 are controlled by constant current and / or constant voltage loops, which will not be elaborated here. Any circuit structure that can realize the function of the control module 22 is applicable to the present invention and is not limited to this embodiment.

[0091] Example 2

[0092] like Figure 4 As shown, this embodiment provides a self-powered control circuit 2, which differs from the first embodiment in that the second switch SW2 adopts a leading-edge modulation method.

[0093] Specifically, the control module 22 includes a reference signal generation unit 221, a comparison unit 222, a delay unit 223, a working voltage modulation unit 224, a first switch driving unit 225, a second switch driving unit 226, and a third switch driving unit 227. The working voltage modulation unit 224 is connected to the working voltage VCC and generates a turn-on signal for the second switch SW2 based on the difference between the working voltage VCC and a preset voltage VCC_ref. A voltage regulator loop is used to bring the working voltage VCC close to or equal to the preset voltage VCC_ref. The second switch driving unit 226 is connected to the output terminals of the comparison unit 222 and the working voltage modulation unit 224. When the current sampling signal Vcs is less than the reference signal Vcs_pre, the second switch SW2 is turned off; and the second switch SW2 is turned on based on the output signal of the working voltage modulation unit 224. The turn-on time of the second switch SW2 is controlled by leading-edge modulation.

[0094] It should be noted that the structure and principle of the other units are the same as in Embodiment 1. Please refer to Embodiment 1 for details, which will not be repeated here.

[0095] Example 3

[0096] like Figure 2 As shown, this embodiment provides a self-powered control chip, which includes:

[0097] The self-powered control circuit 2 in Example 1 or Example 2 has a collector pin C, a working voltage pin VCC, a ground pin GND, and a current sampling pin CS.

[0098] like Figure 2 As shown, the collector pin C is connected to the collector of the transistor Q1; the operating voltage pin VCC is connected to the negative terminal of the first diode D, and an external energy storage capacitor C2 is connected to provide the operating voltage VCC; the ground pin GND is connected to the ground terminals of the second switch SW2 and the third switch SW3. In addition, the reference ground of the drive module 21 and the control module 22 is connected to the ground pin GND (not shown in the figure); the current sampling pin CS is connected to the current sampling signal Vcs, and the current sampling signal Vcs is provided to the control module 22 through an external sampling resistor Rcs2.

[0099] Example 4

[0100] like Figure 5 As shown, this embodiment provides a power supply system, the power supply system comprising:

[0101] The switching power supply circuit and the self-powered control circuit 2 of Embodiment 1 or Embodiment 2, wherein the self-powered control circuit controls the switching power supply circuit to perform power conversion; wherein the switching power supply circuit has a two-winding topology.

[0102] As an example, the switching power supply circuit is a flyback two-winding topology, including an energy storage capacitor C2, a sampling resistor Rcs2, a rectifier 3, a second resistor R1, a third resistor R2, a fourth resistor R3, a fifth resistor R4, a second capacitor C3, a third capacitor C4, a fourth capacitor C5, a second diode D2, and a third diode D3. The rectifier 3 receives an AC input power supply AC and rectifies the AC input power supply AC to obtain a bus voltage. The second capacitor C3 is connected in parallel to the output terminal of the rectifier 3. The collector of the transistor Q1 in the self-powered control circuit 2 is connected to the bus voltage. One end of the primary winding is connected to the sampling terminal of the sampling resistor Rcs2, and the other end is connected to the primary ground. The second resistor R1 and the third resistor R2 are connected in series between the ground of the self-powered control circuit 2 and the primary ground, and provide a voltage feedback signal VFB (the voltage feedback signal VFB is calculated through a current loop to obtain the preset value Vcs_final, which will not be described in detail here). One end of the third capacitor C4 is connected to the sampling terminal of the sampling resistor Rcs2, and the other end is connected to the cathode of the second diode D2; the anode of the second diode D2 is connected to the primary ground. The fourth resistor R3 is connected in parallel across the third capacitor C4. One end of the secondary winding is connected to the anode of the third diode D3, and the other end is connected to the secondary ground. The cathode of the third diode D3 is connected to the secondary ground via the fourth capacitor C5. The fifth resistor R4 is connected in parallel across the fourth capacitor C5 and outputs a DC power supply DC OUT.

[0103] It should be noted that the two-winding topology of the present invention includes, but is not limited to, flyback topology, forward topology, LLC topology, half-bridge topology, and full-bridge topology, and is not limited to this embodiment.

[0104] Example 5

[0105] like Figure 6 As shown, this embodiment provides a self-powered control method, implemented based on the self-powered control circuit of Embodiment 1. The self-powered control method includes:

[0106] 1) Control the second switch SW2 and the first switch SW1 to be turned on, and the third switch SW3 to be turned off, so that the transistor Q1 is turned on.

[0107] Specifically, in this embodiment, the first switch SW1 and the second switch SW2 are first turned on, and the third switch SW3 is turned off. At this time, the base of the transistor Q1 is connected to the drive signal, and the emitter has a path to ground. Therefore, the transistor Q1 is turned on; the current sampling signal Vcs increases linearly.

[0108] 2) When the current sampling signal Vcs increases to the reference signal Vcs_pre, the first switch SW1 is turned off; and the conduction time of the second switch SW2 is controlled based on the difference between the operating voltage VCC and the preset voltage VCC_ref. When the first switch SW1, the second switch SW2 and the third switch SW3 are turned off, the transistor Q1 remains in the conducting state based on the tailing effect.

[0109] Specifically, when the first switch SW1 is off, the second switch SW2 is on, and the third switch SW3 is off, the emitter current of the transistor Q1 charges the energy storage capacitor C2 through the first diode D1, and provides the operating voltage VCC to provide additional power to the driving module 21 of the transistor Q1.

[0110] Specifically, the reference signal Vcs_pre is adjusted based on the comparison result between the current sampling signal Vcs and the preset value Vcs_final. If the maximum value of the current sampling signal Vcs before the transistor Q1 is turned off in the current cycle is greater than the preset value Vcs_final, then the reference signal Vcs_pre is decreased in the next cycle; if the maximum value of the current sampling signal Vcs before the transistor Q1 is turned off in the current cycle is less than the preset value Vcs_final, then the reference signal Vcs_pre is increased in the next cycle. As an example, the current sampling signal Vcs can be compared with the preset value Vcs_final when the third switch SW3 is triggered to conduct, and the reference signal value for the next cycle can be adjusted based on the comparison result. As an example, the adjustment amount of the reference signal Vcs_pre is a fixed step size, or the adjustment amount of the reference signal Vcs_pre is proportional to the difference between the current sampling signal Vcs and the preset value Vcs_final. In this invention, a closed-loop control system that allows the collector current of transistor Q1 to naturally drop to zero adjusts the magnitude of the reference signal Vcs_pre in each switching cycle. Finally, when the collector current of transistor Q1 is turned off at zero, the current sampling signal is a constant value Vcs_final, thereby ensuring constant current accuracy with minimal system impact.

[0111] It should be noted that the preset value Vcs_final is calculated based on the constant current algorithm, which will not be elaborated here.

[0112] Specifically, the turn-off time of the second switch SW2 is controlled by the difference between the operating voltage VCC and the preset voltage VCC_ref, and the operating voltage VCC approaches the preset voltage VCC_ref based on the voltage regulator loop.

[0113] 3) After the first switch SW1 is turned off for a set time, the third switch SW3 is turned on, and the transistor Q1 is completely turned off.

[0114] Specifically, when the first switch SW1 and the second switch SW2 are off and the third switch SW3 is on, the base of the transistor Q1 is pulled low, and no current flows through the transistor Q1. As an example, the second switch SW2 is on at the same time as the third switch SW3 is on.

[0115] It should be noted that the turn-on time of the first switch SW1 and the turn-off time of the third switch SW3 are controlled by constant current and / or constant voltage loops, which will not be elaborated here.

[0116] like Figure 6 As shown, this invention adaptively adjusts the magnitude of the reference signal Vcs_pre in each switching cycle, ultimately ensuring that the current sampling signal Vcs remains constant at a preset value Vcs_final (a constant value) when the collector current of transistor Q1 reaches zero (before transistor Q1 is completely turned off), thus guaranteeing constant current accuracy while minimizing system impact. A set time tdelay proportional to the preset value Vcs_final is set. When the set time tdelay expires (before the third switch SW3 is turned on), it is checked whether the value of the current sampling signal Vcs has reached the preset value Vcs_final. If it has not, it means that the first switch SW1 turned off too early, and the reference signal for the next cycle is increased; conversely, it means that the first switch SW1 turned off too late, and the reference signal for the next cycle is decreased, thereby dynamically adjusting the value of the reference signal Vcs_pre so that the current sampling signal Vcs reaches zero at exactly the preset value Vcs_final. Figure 6As shown, in the first switching cycle, if the value of the current sampling signal Vcs does not reach the preset value Vcs_final before the third switch SW3 is turned on, then in the second switching cycle, the value of the reference signal is increased from Vcs_pre1 to Vcs_pre2; in the second switching cycle, if the value of the current sampling signal Vcs is greater than the preset value Vcs_final before the third switch SW3 is turned on, then in the third switching cycle, the value of the reference signal is decreased from Vcs_pre2 to Vcs_pre3; finally, the current sampling signal Vcs jitters by one LSB (least significant bit) around the preset value Vcs_final.

[0117] like Figure 6 As shown, the voltage regulation loop control of the operating voltage VCC is achieved by dynamically adjusting the trailing edge (turn-off point) of the second switch SW2's on signal. When the first switch SW1 is on for a longer period, the operating voltage VCC consumes more power, and the second switch SW2 needs to turn off earlier to increase the power supply time of the operating voltage VCC; when the first switch SW1 is on for a shorter period, the power consumption of the operating voltage VCC decreases, and the second switch SW2 can delay its turn-off to prevent the operating voltage VCC from overshooting. Figure 6 As shown, in the second switching cycle, the conduction time of the first switch SW1 becomes longer, so the turn-off time of the second switch SW2 is advanced; in the third switching cycle, the conduction time of the first switch SW1 becomes shorter, so the turn-off time of the second switch SW2 is delayed.

[0118] Therefore, the present invention can decouple the regulation of the operating voltage VCC from the control of the collector current of the transistor Q1 to zero, thereby achieving the best effect of maintaining a stable operating voltage VCC while ensuring the safe shutdown of the transistor Q1.

[0119] Example 6

[0120] like Figure 7 As shown, this embodiment provides a self-powered control method. The difference from embodiment five is that the opening time of the second switch SW2 is controlled to achieve voltage regulation of the working voltage VCC.

[0121] Specifically, when the first switch SW1 is turned off, the second switch SW2 is also turned off simultaneously. The collector current of the transistor Q1 immediately charges the working voltage VCC. By adjusting the timing of when the second switch SW2 is turned on again, the charging duration is controlled, thereby adjusting the level of the working voltage VCC.

[0122] like Figure 7As shown, the voltage regulation loop control of the operating voltage VCC is achieved by dynamically adjusting the leading edge (conduction point) of the second switch SW2's conduction signal. When the first switch SW1 is on for a longer period, the operating voltage VCC consumes more power, and the second switch SW2 needs to delay its conduction to increase the power supply time of the operating voltage VCC; when the first switch SW1 is on for a shorter period, the operating voltage VCC consumes less power, and the second switch SW2 can conduct earlier to prevent the operating voltage VCC from overshooting.

[0123] It should be noted that the other control principles are the same as in Example 5, and will not be described in detail here.

[0124] In summary, this invention provides a power supply system, a self-powered control circuit, a chip, and a method, comprising: a transistor, a first diode, a first switch, a second switch, a third switch, a driving module, and a control module; one end of the first switch is connected to the base of the transistor, and the other end is connected to the output terminal of the driving module; one end of the second switch is connected to the emitter of the transistor, and the other end is grounded; one end of the third switch is connected to the base of the transistor, and the other end is grounded; the anode of the first diode is connected to the emitter of the transistor, and the cathode is connected to the input terminal of the driving module; an external energy storage capacitor is connected to the cathode of the first diode, and the energy storage capacitor is used to provide the operating voltage; the control module is connected to the cathode of the first diode and receives a current sampling signal, and controls the switching states of the first switch, the second switch, and the third switch based on the current sampling signal and the operating voltage, wherein the off-time of the first switch is adjusted by the current sampling signal so that the maximum value of the current sampling signal before the transistor is turned off approaches a preset value; the on-time of the second switch is adjusted by the operating voltage so that the operating voltage approaches a preset voltage. The power supply system, self-powered control circuit, chip, and method of this invention employ a dual closed-loop control architecture of adaptive collector current control to zero and VCC voltage regulation. This ensures stable operating voltage while allowing the transistor collector current to naturally drop to zero, minimizing system impact. Simultaneously, it maintains a constant current sampling signal when the transistor collector current drops to zero, thus guaranteeing the constant current accuracy of the system's constant current segment. Therefore, this invention effectively overcomes various shortcomings of existing technologies and possesses high industrial applicability.

[0125] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A self-powered control circuit, characterized in that, The self-powered control circuit includes at least: Transistor, first diode, first switch, second switch, third switch, driver module and control module; One end of the first switch is connected to the base of the transistor, and the other end is connected to the output of the drive module; One end of the second switch is connected to the emitter of the transistor, and the other end is grounded; One end of the third switch is connected to the base of the transistor, and the other end is grounded; The anode of the first diode is connected to the emitter of the transistor, and the cathode is connected to the input terminal of the drive module; the cathode of the first diode is connected to an energy storage capacitor outside the self-powered control circuit, and the energy storage capacitor is used to provide the operating voltage. The control module is connected to the negative terminal of the first diode and receives a current sampling signal. Based on the current sampling signal and the operating voltage, it controls the switching states of the first switch, the second switch, and the third switch. Specifically, in the current switching cycle, when the current sampling signal increases to a reference signal, the first switch is turned off; the third switch is turned on after the first switch has been off for a set time; when the third switch is triggered to turn on, the maximum value of the current sampling signal before the transistor turns off in the current cycle is compared with a preset value, and the reference signal for the next cycle is adjusted based on the comparison result. If the maximum value of the current sampling signal before the transistor turns off in the current cycle is greater than the preset value, the reference signal is decreased in the next cycle; if the maximum value of the current sampling signal before the transistor turns off in the current cycle is less than the preset value, the reference signal is increased in the next cycle. Closed-loop control based on the natural zeroing of the transistor's collector current ensures that the maximum value of the current sampling signal before the transistor turns off approaches the preset value. The on-time of the second switch is adjusted by the current sampling signal and the operating voltage to ensure that the operating voltage approaches the preset voltage.

2. The self-powered control circuit according to claim 1, characterized in that: The control module includes a reference signal generation unit, a comparison unit, a delay unit, a working voltage modulation unit, a first switch driving unit, a second switch driving unit, and a third switch driving unit; The reference signal generation unit receives the current sampling signal, compares the current sampling signal with a preset value, and adjusts and generates a reference signal based on the comparison result. The comparison unit is connected to the output terminal of the reference signal generation unit and receives the current sampling signal, comparing the reference signal with the current sampling signal; The first switch driving unit is connected to the output terminal of the comparison unit, and turns off the first switch when the current sampling signal is less than the reference signal; The delay unit is connected to the output terminal of the comparison unit and delays the output signal of the comparison unit for a set time, wherein the set time is proportional to the preset value. The third switch driving unit is connected to the output terminal of the delay unit, and turns on the third switch after the first switch turns off for the set time; The working voltage modulation unit is connected to the working voltage and generates a turn-off signal for the second switch based on the difference between the working voltage and the preset voltage. The second switch driving unit is connected to the output terminal of the delay unit and the working voltage modulation unit. When the third switch is turned on, the second switch is turned on, and the second switch is turned off based on the output signal of the working voltage modulation unit.

3. The self-powered control circuit according to claim 1, characterized in that: The control module includes a reference signal generation unit, a comparison unit, a delay unit, a working voltage modulation unit, a first switch driving unit, a second switch driving unit, and a third switch driving unit; The reference signal generation unit receives the current sampling signal, compares the current sampling signal with a preset value, and adjusts and generates a reference signal based on the comparison result. The comparison unit is connected to the output terminal of the reference signal generation unit and receives the current sampling signal, comparing the reference signal with the current sampling signal; The first switch driving unit is connected to the output terminal of the comparison unit, and turns off the first switch when the current sampling signal is less than the reference signal; The delay unit is connected to the output terminal of the comparison unit and delays the output signal of the comparison unit for a set time, wherein the set time is proportional to the preset value. The third switch driving unit is connected to the output terminal of the delay unit, and turns on the third switch after the first switch turns off for the set time; The working voltage modulation unit is connected to the working voltage and generates a conduction signal for the second switch based on the difference between the working voltage and the preset voltage; The second switch driving unit is connected to the output terminal of the comparison unit and the working voltage modulation unit. When the first switch is turned off, the second switch is turned off, and the second switch is turned on based on the output signal of the working voltage modulation unit.

4. The self-powered control circuit according to claim 2 or 3, characterized in that: The reference signal generation unit includes a comparator and a logic subunit; the input of the comparator is connected to the preset value and the current sampling signal, and the preset value is compared with the current sampling signal; the logic subunit generates an initial value of the reference signal in an initial state, and then adjusts the reference signal based on the output signal of the comparator; wherein, the initial value of the reference signal is the product of the preset value and a coefficient less than 1.

5. A self-powered control chip, characterized in that, The self-powered control chip includes at least: The self-powered control circuit as described in any one of claims 1-4 includes a collector pin connected to the collector of the transistor, a working voltage pin connected to the negative terminal of the first diode, a grounding pin connected to the ground terminals of the second switch and the third switch, and a current sampling pin connected to the current sampling signal.

6. A power supply system, characterized in that, The power supply system includes at least: The switching power supply circuit and the self-powered control circuit as described in any one of claims 1-4, wherein the self-powered control circuit controls the switching power supply circuit to perform power conversion; wherein the switching power supply circuit has a two-winding topology.

7. A self-powered control method, implemented based on the self-powered control circuit as described in any one of claims 1-4, characterized in that, The self-powered control method includes at least the following: The second switch and the first switch are turned on, the third switch is turned off, and the transistor is turned on. When the current sampling signal increases to the reference signal, the first switch is turned off; and the conduction time of the second switch is controlled based on the difference between the operating voltage and the preset voltage; when the first switch, the second switch and the third switch are turned off, the transistor remains in the conducting state based on the tailing effect; After the first switch is turned off for a set time, the third switch is turned on, and the transistor is completely turned off. Specifically, the reference signal is adjusted based on the comparison result between the current sampling signal and the preset value. If the maximum value of the current sampling signal before the transistor is turned off in the current cycle is greater than the preset value, the reference signal is decreased in the next cycle. If the maximum value of the current sampling signal before the transistor is turned off in the current cycle is less than the preset value, the reference signal is increased in the next cycle.

8. The self-powered control method according to claim 7, characterized in that: The preset value is calculated based on the constant current algorithm.

9. The self-powered control method according to claim 7, characterized in that: The adjustment amount of the reference signal is a fixed step size; or the adjustment amount of the reference signal is proportional to the difference between the current sampling signal and the preset value.

10. The self-powered control method according to any one of claims 7-9, characterized in that: The off time of the second switch is determined based on the difference between the operating voltage and the preset voltage.

11. The self-powered control method according to claim 10, characterized in that: At the same time that the third switch is turned on, the second switch is also turned on.

12. The self-powered control method according to any one of claims 7-9, characterized in that: The conduction time of the second switch is determined based on the difference between the operating voltage and the preset voltage.

13. The self-powered control method according to claim 12, characterized in that: The second switch is turned off at the same time as the first switch is turned off.

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