Pulse current control method, control device and switching power supply

Abstract

The application discloses a pulse current control method, a control device and a switching power supply. The switching power supply comprises a constant current output power supply, an inductor and a bypass tube which are connected in series. The control signal of the main power tube of the constant current output power supply is a first control signal. One end of the bypass tube is the positive output end of the switching power supply, and the other end is the negative output end of the switching power supply. The output current of the switching power supply is pulse current by controlling the turn-on and turn-off of the bypass tube. The pulse current control method comprises the following steps: adjusting the control amount of the first control signal according to the working state of the switching power supply; when the switching power supply is in the pulse current output stable period, adjusting the control amount according to the comparison result of the loop error signal and the triangular wave signal, so that the output current of the switching power supply tends to be the target current; when the switching power supply is in the pulse current output rising period, the control amount is a set value, so as to inhibit the insufficient energy output of the switching power supply from causing the under-pulse. The application can improve the waveform quality of the pulse current.

Description

Technical Field

[0001] This invention relates to the field of power supply technology, and in particular to a pulse current control method, control device, and switching power supply. Background Technology

[0002] Existing high-power semiconductor laser pulsed current source power converters primarily operate in linear mode. Compared to linear mode pulsed current sources, current sources operating in switch-modulated mode are more efficient and have a wider adjustment range, but they also present several challenges, such as requiring very fast pulse current edges (µs-level rise and fall times) and low current ripple. Furthermore, switch-modulated current sources, due to limitations in switching frequency and control loop bandwidth, cannot respond promptly to transient pulse signals, resulting in undershoot on the rise of the output current. Summary of the Invention

[0003] In view of this, the technical problem to be solved by the present invention is to provide a pulse current control method, control device and switching power supply, which at least to some extent solves one of the technical problems existing in the prior art.

[0004] As a first aspect of the present invention, the technical solution of the provided pulse current control method is as follows:

[0005] A pulse current control method is applied to a switching power supply, the switching power supply including a constant current output power supply, an inductor, and a bypass transistor connected in series. The control signal of the main power transistor of the constant current output power supply is a first control signal. One end of the bypass transistor is the positive output terminal of the switching power supply, and the other end is the negative output terminal of the switching power supply. By controlling the switching on and off of the bypass transistor, the output current of the switching power supply is made to be the pulse current. The pulse current control method includes: Adjust the control quantity of the first control signal according to the operating state of the switching power supply: When the switching power supply is in the stable period of pulse current output, a closed-loop control strategy is adopted to adjust the control quantity according to the comparison result of the loop error signal and the triangular wave signal, so that the output current of the switching power supply tends to the target current. When the switching power supply is in the rising phase of the pulse current output, an open-loop control strategy is adopted, and the control quantity is a set value to suppress undershoot caused by insufficient energy output from the switching power supply.

[0006] Optionally, adjusting the control amount of the first control signal according to the operating state of the switching power supply includes: The first control signal comes from the first original control signal, which is a PWM square wave with a duty cycle of 50% and including dead time. Obtain the error signal characterizing the deviation between the inductor current and the target current, and use it as the loop error signal; A triangular wave signal is generated, and the triangular wave signal is synchronized with the first control signal; The loop error signal and the triangular wave signal are compared to generate a chopping signal: the chopping signal is generated when the triangular wave signal touches the loop error signal during its rising process, but the chopping signal is shielded when the switching power supply is in the rising period of the pulse current output. The first control signal is generated by processing the first original control signal based on the chopping signal: when the chopping signal is generated, the signal after the first original control signal is shielded and used as the first control signal; when the chopping signal is not generated, the first original control signal is directly used as the first control signal.

[0007] As a first aspect of the present invention, the technical solution of the provided embodiment of the pulse current control device is as follows: A pulse current control device is applied to a switching power supply, the switching power supply including a constant current output power supply, an inductor, and a bypass transistor connected in series. The control signal of the main power transistor of the constant current output power supply is a first control signal. One end of the bypass transistor is the positive output terminal of the switching power supply, and the other end is the negative output terminal of the switching power supply. By controlling the switching on and off of the bypass transistor, the output current of the switching power supply is made to be the pulse current. The pulse current control device is configured as follows: Adjust the control quantity of the first control signal according to the operating state of the switching power supply: When the switching power supply is in the stable period of pulse current output, a closed-loop control strategy is adopted to adjust the control quantity according to the comparison result of the loop error signal and the triangular wave signal, so that the output current of the switching power supply tends to the target current. When the switching power supply is in the rising phase of the pulse current output, an open-loop control strategy is adopted, and the control quantity is a set value to suppress undershoot caused by insufficient energy output from the switching power supply.

[0008] Optionally, the pulse current control device includes: The first original control signal generation unit is used to generate a first original control signal. The first control signal comes from the first original control signal. The first original control signal is a PWM square wave with a duty cycle of 50% and including a dead time. The loop error signal acquisition unit is used to acquire an error signal characterizing the deviation between the inductor current and the target current, as the loop error signal; A triangular wave signal generation unit is used to generate a triangular wave signal, which is synchronized with the first control signal; The chopping signal generation unit is used to compare the loop error signal and the triangular wave signal to generate a chopping signal: the chopping signal is generated when the triangular wave signal touches the loop error signal during its rising process, but the chopping signal is shielded when the switching power supply is in the rising period of the pulse current output. The first control signal generation unit is used to process the first original control signal according to the chopping signal to generate the first control signal: when the chopping signal is generated, the signal after the first original control signal is shielded and used as the first control signal when the chopping signal is generated; when the chopping signal is not generated, the first original control signal is directly used as the first control signal.

[0009] Optionally, the loop error signal acquisition unit includes an error amplifier, resistors R3 and R4, capacitors C2 and C3. One end of resistor R3 is connected to a current sampling signal IFB representing the magnitude of the inductor current. The other end of resistor R3 is simultaneously connected to the inverting input terminal of the error amplifier, one end of resistor R4, and one end of capacitor C3. The non-inverting input terminal of the error amplifier is connected to a reference voltage IREF representing the magnitude of the target current. The other end of resistor R4 is connected to one end of capacitor C2. The other ends of capacitor C3, the other ends of capacitor C2, and the output terminal of the error amplifier are connected together to output the loop error signal.

[0010] Optionally, the triangular wave signal generating unit includes resistors R1 and R2, switching transistors Q1 and Q2, and capacitor C1. One end of resistor R1 and one end of resistor R2 are connected together for inputting the supply voltage Vdd. The other end of resistor R1 is connected to one end of switching transistor Q1 and the control terminal of switching transistor Q2. The control terminal of switching transistor Q1 is connected to the first control signal. The other end of resistor R2, one end of switching transistor Q2, and one end of capacitor C1 are connected together to output the triangular wave signal. The other ends of switching transistor Q1, the other end of switching transistor Q2, and the other end of capacitor C1 are used for grounding.

[0011] Optionally, the chopping signal generation unit includes a comparator and a switching transistor Q3. The loop error signal is input to the inverting input terminal of the comparator, the triangular wave signal is input to the non-inverting input terminal of the comparator, the output terminal of the comparator is connected to one end of the switching transistor Q3 to output the chopping signal, the control terminal of the switching transistor Q3 is input to the second control signal, and the other end of the switching transistor Q3 is grounded. Wherein: when the inductor current is greater than the set threshold, the second control signal controls the switch Q3 to turn off; when the inductor current is less than or equal to the set threshold, the second control signal controls the switch Q3 to turn on.

[0012] As a third aspect of the present invention, the technical solution of the provided switching power supply embodiment is as follows: A switching power supply includes a constant current output power supply, an inductor, and a bypass transistor connected in series. The control signal for the main power transistor of the constant current output power supply is a first control signal. One end of the bypass transistor is the positive output terminal of the switching power supply, and the other end is the negative output terminal of the switching power supply. The output current of the switching power supply is the pulse current by controlling the switching on and off of the bypass transistor. The power supply also includes the pulse current control device described in any of the second aspects above.

[0013] Optionally, the constant current output power supply is an isolated switching power supply, and the primary side of the isolated power supply is a full-bridge circuit.

[0014] The advantages of this invention compared to the prior art are as follows: (1) The embodiment of the present invention adopts loop control, and adjusts the control quantity of the first control signal according to the comparison result of the loop error signal and the triangular wave signal, and outputs the first control signal in real time, which can improve the transient performance of the switching power supply; (2) In the embodiment of the present invention, when the switching power supply is in the rising period of the pulse current output, the control quantity of the first control signal is a set value, which can effectively suppress the undershoot of the rising edge of the pulse current waveform caused by insufficient energy output by the constant current power supply, and improve the waveform quality of the pulse current. Attached Figure Description

[0015] Figure 1 For the present invention An embodiment of a switching power supply Structural diagram; Figure 2 This is a schematic diagram of an embodiment of the loop error signal acquisition unit of the present invention; Figure 3 This is a schematic diagram of an embodiment of the triangular wave signal generation unit of the present invention; Figure 4 for Figure 3 Waveform diagram generated by the triangular wave signal generation unit; Figure 5 This is a schematic diagram of an embodiment of the chopping signal generation unit of the present invention; Figure 6 for Figure 1 Flowchart of the MCU's internal driver chopping logic; Figure 7 for Figure 1 The second control signal generation logic flowchart; Figure 8 for Figure 1 Flowchart of the internal pulse circuit control logic of the MCU; Figure 9This is a schematic diagram of a steady-state waveform of the switching power supply of the present invention; Figure 10 This is a simulation waveform diagram of the pulse current output by the switching power supply of the present invention when it rises. Detailed Implementation

[0016] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0017] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0018] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be used interchangeably where appropriate for the purposes of describing embodiments of this application herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0019] It should be understood that in the specification, claims, and drawings, when a step is described as continuing into another step, the step may directly continue into that other step or be continued into that other step through a third step; when an element / unit is described as being "connected" to another element / unit, the element / unit may be "directly connected" to that other element / unit or be "connected" to that other element / unit through a third element / unit.

[0020] Furthermore, the accompanying drawings are merely illustrative of this disclosure and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and therefore repeated descriptions thereof will be omitted. Some block diagrams shown in the drawings are functional entities and do not necessarily correspond to physically or logically independent entities. These functional entities can be implemented in software, in one or more hardware modules or integrated circuits, or in different network and / or processor devices and / or microcontroller devices.

[0021] In some implementations, please refer to Figure 1 A pulse current control method is disclosed, which is applied to a switching power supply. The switching power supply includes a constant current output power supply, an inductor L, and a bypass transistor Q4 connected in series. Figure 1 In this diagram, diode LD represents the laser load. The control signal for the main power transistor of the constant current output power supply is the first control signal. One end of the bypass transistor Q4 is the positive output terminal of the switching power supply, and the other end is the negative output terminal. The third control signal controls the switching on and off of the bypass transistor to achieve a pulsed current output from the switching power supply. Pulse current control methods include: Adjust the control quantity of the first control signal according to the operating state of the switching power supply: When the switching power supply is in the stable period of pulse current output, a closed-loop control strategy is adopted. The control quantity is adjusted according to the comparison result of the loop error signal and the triangular wave signal so that the output current of the switching power supply tends to the target current. When the switching power supply is in the rising phase of the pulse current output, an open-loop control strategy is adopted, with the control quantity being the set value, to suppress undershoot caused by insufficient energy output from the switching power supply.

[0022] The above-mentioned pulse current control method adopts a loop control strategy, which adjusts the control quantity of the first control signal based on the comparison result of the loop error signal and the triangular wave signal, and outputs the first control signal in real time, which can improve the transient performance of the switching power supply. At the same time, when the switching power supply is in the rising period of the pulse current output, the control quantity of the first control signal is a set value, which can effectively suppress the undershoot of the rising edge of the pulse current waveform caused by insufficient energy output of the constant current power supply, and improve the waveform quality of the pulse current.

[0023] As an example, the control quantity of the first control signal is the duty cycle. When the switching power supply is in the rising period of the pulse current output, the control quantity is the maximum duty cycle, that is, the set value is set to the maximum duty cycle.

[0024] As an example, the constant current output power supply is an isolated switching power supply. The primary side of the isolated power supply is a full-bridge circuit. Therefore, the main power switching transistors of the constant current output power supply include four switching transistors in the full-bridge circuit. The first control signal includes a first control signal A for controlling the first diagonal switching transistor and a first control signal B for controlling the second diagonal switching transistor. The first control signal A and the first control signal B need to maintain symmetrical duty cycles and have a phase difference of 180°.

[0025] As an example, adjusting the control quantity of the first control signal according to the operating state of the switching power supply includes: The first control signal comes from the first original control signal, which is a PWM square wave with a duty cycle of 50% and a dead time. Obtain the error signal characterizing the deviation between the inductor current and the target current, and use it as the loop error signal Vcomp; A triangular wave signal Vc is generated, and the triangular wave signal Vc is synchronized with the first control signal. The loop error signal Vcomp and the triangular wave signal Vc are compared to generate the chopping signal Chop: the chopping signal Chop is generated when the triangular wave signal Vc touches the loop error signal Vcomp during the rising process, but the chopping signal Chop is shielded when the switching power supply is in the rising period of the pulse current output. The first control signal is generated by processing the first original control signal based on the chop signal: when the chop signal is generated, the signal after the first original control signal is shielded and used as the first control signal; when the chop signal is not generated, the first original control signal is directly used as the first control signal.

[0026] In some embodiments, a pulse current control device is disclosed, applied to Figure 1 This type of switching power supply includes a constant current output power supply, an inductor L, and a bypass transistor Q4 connected in series. The control signal for the main power transistor of the constant current output power supply is the first control signal. One end of the bypass transistor Q4 is the positive output terminal of the switching power supply, and the other end is the negative output terminal. The switching on and off of the bypass transistor is controlled by a third control signal to achieve a pulsed output current for the switching power supply. The pulsed current control device is configured as follows: Adjust the control quantity of the first control signal according to the operating state of the switching power supply: When the switching power supply is in the stable period of pulse current output, a closed-loop control strategy is adopted. The control quantity is adjusted according to the comparison result of the loop error signal and the triangular wave signal, so that the output current of the switching power supply tends to the target current. When the switching power supply is in the rising phase of the pulse current output, an open-loop control strategy is adopted, with the control quantity being the set value, to suppress undershoot caused by insufficient energy output from the switching power supply.

[0027] As an example, the pulse current control device includes: The first original control signal generation unit is used to generate a first original control signal. The first control signal comes from the first original control signal, which is a PWM square wave with a duty cycle of 50% and including a dead time. The loop error signal acquisition unit is used to acquire the error signal characterizing the deviation between the inductor current and the target current, as the loop error signal Vcomp; The triangular wave signal generation unit is used to generate a triangular wave signal Vc, which is synchronized with the first control signal. The chopping signal generation unit is used to compare the loop error signal Vcomp and the triangular wave signal Vc to generate a chopping signal Chop: when the triangular wave signal Vc touches the loop error signal Vcomp during its rising process, the chopping signal Chop is generated, but when the switching power supply is in the rising period of the pulse current output, the chopping signal Chop is shielded. The first control signal generation unit is used to process the first original control signal based on the chop signal to generate the first control signal: when the chop signal is generated, the signal after the first original control signal is shielded and used as the first control signal when the chop signal is generated; when the chop signal is not generated, the first original control signal is directly used as the first control signal.

[0028] As an example, please see Figure 2 The loop error signal acquisition unit includes an error amplifier, resistors R3 and R4, and capacitors C2 and C3. One end of resistor R3 is connected to the current sampling signal IFB, which represents the magnitude of the inductor current. The other end of resistor R3 is connected to the inverting input of the error amplifier, one end of resistor R4, and one end of capacitor C3. The non-inverting input of the error amplifier is connected to the reference voltage IREF, which represents the magnitude of the target current. The other end of resistor R4 is connected to one end of capacitor C2. The other ends of capacitors C3 and C2 are connected together with the output of the error amplifier to output the loop error signal Vcomp. Resistor R4, capacitor C2, and capacitor C3 form a feedback network, which compensates for the current error through the error amplifier and outputs the Vcomp signal.

[0029] As an example, the error amplifier uses an operational amplifier with a high slew rate.

[0030] As an example, please see Figure 3 The triangular wave signal generation unit includes resistors R1 and R2, switching transistors Q1 and Q2, and capacitor C1. One end of resistor R1 and one end of resistor R2 are connected together to input the supply voltage Vdd. The other end of resistor R1 is connected to one end of switching transistor Q1 and the control terminal of switching transistor Q2. The control terminal of switching transistor Q1 is connected to the first control signal. The other end of resistor R2, one end of switching transistor Q2, and one end of capacitor C1 are connected together to output the triangular wave signal. The other ends of switching transistors Q1, Q2, and C1 are used for grounding. Switch Q1 is connected in series with resistor R1 to drive switching transistor Q2. Resistor R2 and capacitor C1 are connected in series to form an RC charging circuit. Switch Q2 is connected in parallel across capacitor C1. By turning on switching transistor Q2, capacitor C1 is short-circuited, and the potential of capacitor C1 is rapidly pulled low. Please refer to the waveform diagram generated by the triangular wave signal generation unit. Figure 4When the first control signal A is low, switch Q1 is turned off. At this time, switch Q2 is turned on through the supply voltage Vdd and resistor R1 circuit, capacitor C1 is short-circuited, and Vcomp output is low. When the first control signal A is high, switch Q1 is turned on and switch Q2 is turned off. Capacitor C1 is charged through the supply voltage Vdd and resistor R2 circuit, forming a triangular wave.

[0031] As an example, please see Figure 5 The chop signal generation unit includes a comparator and a switch Q3. The inverting input of the comparator receives the loop error signal Vcomp, and the non-inverting input of the comparator receives the triangular wave signal Vc. The output of the comparator is connected to one end of the switch Q3 to output the chop signal Chop. The control terminal of the switch Q3 receives the second control signal, and the other end of the switch Q3 is grounded. Specifically: when the inductor current is greater than the set threshold, it indicates that the switching power supply is in the stable period of pulse current output, and the second control signal controls the switch Q3 to turn off. The second control signal has no effect on the chopping signal Chop. When the inductor current is less than or equal to the set threshold, it indicates that the switching power supply is in the rising period of pulse current output, and the second control signal controls the switch Q3 to turn on, which has a pull-down effect on the chopping signal Chop.

[0032] As an example, please see Figure 1 The second and third control signals are generated by the MCU. The MCU has a pulse current control logic unit, a drive chopping logic unit, and a second control signal generation logic unit.

[0033] As an example, an MCU that can select PWM waves that can follow master and slave signals, and whose output duty cycles of master and slave PWM waves are the same, such as the Hi3071.

[0034] Based on the above MCU structure Figure 1The circuit operates as follows: The loop calculation unit calculates the loop error signal Vcomp in real time. Simultaneously, the chopping signal generation unit compares the loop error signal Vcomp with the triangular wave signal Vc generated by the triangular wave generation unit in real time and outputs a chopping signal Chop. The chopping signal Chop is also affected by the second control signal. The chopping signal chops the original PWM signal of the MCU, outputting two first control signals with the same duty cycle and 180° phase shift. The chopping signal determines the actual duty cycle. The triangular wave generation unit generates a triangular wave based on the first control signal A, and the amplitude of the triangular wave is controlled by the duty cycle of the first control signal A. When no pulse current is output, the pulse current control logic unit outputs a third control signal to turn on the switch Q4, bypassing the inductor current. At this time, the loop error signal Vcomp will be very small, and the duty cycle of the first control signal only needs to be very small to maintain the inductor current at the target current. When a pulsed current output is required, the third control signal turns off the switch Q4, and the inductor current flows through the load LD. At the instant Q4 turns off, the loop error signal Vcomp rises to its steady-state value. The second control signal generation logic unit outputs a second control signal to pull down the chopping signal Chop. At this time, the original control signal of the first control signal is not chopped, resulting in a large duty cycle output to compensate for the undershoot caused by insufficient energy at the moment of pulse output. During the stable pulsed current output period, the loop operates normally.

[0035] As an example, for Figure 1 The primary side of the constant current output power supply is a full-bridge switching power supply; please refer to [link / reference]. Figure 6 The specific working steps of driving the chopping logic unit are as follows: Step 1: The MCU generates the first raw control signal. Specifically, the internal PWM module generates a set of PWM signals with a 50% duty cycle and a dead zone, and a phase shift of 180°. Step 2: The MCU chops the first original signal according to the input chop signal Chop, generating two PWM waves with 180° phase shift and symmetrical duty cycles. Step 3: Generate the first control signal output.

[0036] For example, please refer to the waveform diagram of the first control signal generation. Figure 9At the rising edge of the first original control signal, capacitor C1 begins charging. When the triangular wave signal Vc touches the loop error signal Vcomp, a chopping signal Chop is generated. When the MCU detects the rising edge of the chopping signal Chop, it chops the first original control signal and outputs the first control signal. The first control signal A is pulled low at the rising edge of Chop, and switch Q1 is turned off. At this time, switch Q2 is turned on through the supply voltage Vdd and resistor R1. Therefore, at the moment the first control signal A is pulled low, the voltage across capacitor C1 is pulled to ground, and the chopping signal Chop will output a low level, forming a small pulse. At the same time, the first control signal B is also chopped by the same pulse width as the first control signal A, thus making the duty cycles of the first control signal A and the first control signal B symmetrical. The logic of the next switching cycle is the same. When the second control signal pulls Chop low, the first original control signal is not chopped, and the first control signal will output a large duty cycle.

[0037] As an example, for Figure 1 The primary side of the constant current output power supply is a full-bridge switching power supply; please refer to [link / reference]. Figure 7 The specific working steps of the second control signal generation logic unit are as follows: Step 1: The MCU's internal comparator compares the sampled inductor current with the set threshold. Step two: Generate a second control signal based on the comparison result.

[0038] Specifically, when the inductor current is greater than the set threshold, it indicates that the switching power supply is in the stable period of pulse current output. The generated second control signal will control the switch Q3 to turn off, which has no effect on the chopping signal Chop. When the inductor current is less than or equal to the set threshold, it indicates that the switching power supply is in the rising period of pulse current output. The generated second control signal will control the switch Q3 to turn on, which will have a pull-down effect on the chopping signal Chop.

[0039] As an example, for Figure 1 The primary side of the constant current output power supply is a full-bridge switching power supply; please refer to [link / reference]. Figure 8 The specific working steps of the pulse current control logic unit are as follows: Step 1: Obtain the pulse current output command; Step two: Generate a third control signal based on the output command to control the output of the pulse current.

[0040] As an example, please refer to Figure 10The horizontal axis represents time, and the vertical axis represents the current in inductor L (IL) and the pulse current output by the switching power supply (Io). When the pulse output current is 35A, without the second control signal (dashed line), the inductor current is at its lowest at 31.8A, with an undershoot of around 3.2A. After the second control signal is applied (solid line), the inductor current is at its lowest at 33.4A, with an undershoot of around 1.6A, and the undershoot recovery time is also shortened. Simulation results show that the proposed control method can accelerate transient response, reduce undershoot, and shorten recovery time.

[0041] In summary, the above embodiments employ hardware loop and software waveform generation. The hardware loop controls the real-time output duty cycle, overcoming the inherent periodic delay of PWM control and improving transient response. At the same time, it also employs drive chopping logic to pull down the chopping signal on the rising edge of the pulse current output and output a large duty cycle first control signal to suppress undershoot on the rising edge of the pulse current. This has a significant advantage in applications requiring current rise and fall in the microsecond range.

[0042] The above content only illustrates the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept of the present invention shall fall within the scope of protection of the claims of the present invention.

Claims

1. A pulse current control method applied to a switching power supply, the switching power supply comprising a constant current output power supply, an inductor, and a bypass transistor connected in series, wherein the control signal of the main power transistor of the constant current output power supply is a first control signal, one end of the bypass transistor is the positive output terminal of the switching power supply, and the other end is the negative output terminal of the switching power supply, wherein the output current of the switching power supply is the pulse current by controlling the switching on and off of the bypass transistor, characterized in that... The pulse current control method includes: Adjust the control quantity of the first control signal according to the operating state of the switching power supply: When the switching power supply is in the stable period of pulse current output, a closed-loop control strategy is adopted to adjust the control quantity according to the comparison result of the loop error signal and the triangular wave signal, so that the output current of the switching power supply tends to the target current. When the switching power supply is in the rising phase of the pulse current output, an open-loop control strategy is adopted, and the control quantity is a set value to suppress undershoot caused by insufficient energy output from the switching power supply.

2. The pulse current control method according to claim 1, characterized in that, The control quantity of adjusting the first control signal according to the operating state of the switching power supply includes: The first control signal comes from the first original control signal, which is a PWM square wave with a duty cycle of 50% and including dead time. Obtain the error signal characterizing the deviation between the inductor current and the target current, and use it as the loop error signal; A triangular wave signal is generated, and the triangular wave signal is synchronized with the first control signal; The loop error signal and the triangular wave signal are compared to generate a chopping signal: the chopping signal is generated when the triangular wave signal touches the loop error signal during its rising process, but the chopping signal is shielded when the switching power supply is in the rising period of the pulse current output. The first control signal is generated by processing the first original control signal based on the chopping signal: when the chopping signal is generated, the signal after the first original control signal is shielded and used as the first control signal; when the chopping signal is not generated, the first original control signal is directly used as the first control signal.

3. A pulse current control device, applied to a switching power supply, wherein the switching power supply includes a constant current output power supply, an inductor, and a bypass transistor connected in series, wherein the control signal of the main power transistor of the constant current output power supply is a first control signal, one end of the bypass transistor is the positive output terminal of the switching power supply, and the other end is the negative output terminal of the switching power supply, wherein the output current of the switching power supply is the pulse current by controlling the switching on and off of the bypass transistor, characterized in that... The pulse current control device is configured to include: An execution circuit is used to adjust the control amount of the first control signal according to the operating state of the switching power supply. When the switching power supply is in the stable period of pulse current output, a closed-loop control strategy is adopted to adjust the control quantity according to the comparison result of the loop error signal and the triangular wave signal, so that the output current of the switching power supply tends to the target current. When the switching power supply is in the rising phase of the pulse current output, an open-loop control strategy is adopted, and the control quantity is a set value to suppress undershoot caused by insufficient energy output from the switching power supply.

4. The pulse current control device according to claim 3, characterized in that, The pulse current control device execution circuit includes: The first original control signal generation unit is used to generate a first original control signal. The first control signal comes from the first original control signal. The first original control signal is a PWM square wave with a duty cycle of 50% and including a dead time. The loop error signal acquisition unit is used to acquire an error signal characterizing the deviation between the inductor current and the target current, as the loop error signal; A triangular wave signal generation unit is used to generate a triangular wave signal, which is synchronized with the first control signal; The chopping signal generation unit is used to compare the loop error signal and the triangular wave signal to generate a chopping signal: the chopping signal is generated when the triangular wave signal touches the loop error signal during its rising process, but the chopping signal is shielded when the switching power supply is in the rising period of the pulse current output. The first control signal generation unit is used to process the first original control signal according to the chopping signal to generate the first control signal: when the chopping signal is generated, the signal after the first original control signal is shielded and used as the first control signal when the chopping signal is generated; when the chopping signal is not generated, the first original control signal is directly used as the first control signal.

5. The pulse current control device according to claim 4, characterized in that: The loop error signal acquisition unit includes an error amplifier, resistors R3 and R4, capacitors C2 and C3. One end of resistor R3 is connected to the current sampling signal IFB, which represents the magnitude of the inductor current. The other end of resistor R3 is connected to the inverting input of the error amplifier, one end of resistor R4, and one end of capacitor C3. The non-inverting input of the error amplifier is connected to the reference voltage IREF, which represents the magnitude of the target current. The other end of resistor R4 is connected to one end of capacitor C2. The other ends of capacitor C3, the other ends of capacitor C2, and the output of the error amplifier are connected together to output the loop error signal.

6. The pulse current control device according to claim 4, characterized in that: The triangular wave signal generating unit includes resistors R1 and R2, switching transistors Q1 and Q2, and capacitor C1. One end of resistor R1 and one end of resistor R2 are connected together to input the supply voltage Vdd. The other end of resistor R1 is connected to one end of switching transistor Q1 and the control terminal of switching transistor Q2. The control terminal of switching transistor Q1 is connected to the first control signal. The other end of resistor R2, one end of switching transistor Q2, and one end of capacitor C1 are connected together to output the triangular wave signal. The other ends of switching transistor Q1, the other end of switching transistor Q2, and the other end of capacitor C1 are used for grounding.

7. The pulse current control device according to claim 4, characterized in that: The chopping signal generation unit includes a comparator and a switching transistor Q3. The loop error signal is input to the inverting input terminal of the comparator, and the triangular wave signal is input to the non-inverting input terminal of the comparator. The output terminal of the comparator is connected to one end of the switching transistor Q3 to output the chopping signal. The control terminal of the switching transistor Q3 is input to the second control signal, and the other end of the switching transistor Q3 is grounded. Wherein: when the inductor current is greater than the set threshold, the second control signal controls the switch Q3 to turn off; when the inductor current is less than or equal to the set threshold, the second control signal controls the switch Q3 to turn on.

8. A switching power supply, comprising a constant current output power supply, an inductor, and a bypass transistor connected in series, wherein the control signal for the main power transistor of the constant current output power supply is a first control signal, one end of the bypass transistor is the positive output terminal of the switching power supply, and the other end is the negative output terminal of the switching power supply, wherein the output current of the switching power supply is the pulse current by controlling the switching on and off of the bypass transistor, characterized in that: It also includes the pulse current control device according to any one of claims 3 to 7.

9. The switching power supply according to claim 8, characterized in that: The constant current output power supply is an isolated switching power supply, and the primary side of the isolated power supply is a full-bridge circuit.

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