A high-side current indirect sampling method based on FSBB quasi-peak current control strategy

Abstract

The application provides a high-side current indirect sampling method based on a FSBB quasi-peak current control strategy, and belongs to the technical field of current indirect sampling. The application comprises the following steps: step one: connecting an indirect current sampling circuit with the FSBB converter; the current waveform reproduction circuit of the indirect current sampling circuit is composed of an operational amplifier and a triode to form a voltage-controlled current source and a current mirror, and the capacitor is controllably charged with a periodic constant current; during the charging process, the voltage of the capacitor rises at a fixed slope; then the sampling waveform is reproduced through signal difference, the accurate reproduction of the inductance current at a megahertz frequency is realized, and adjustable gain is provided; step two: the amplification circuit of the indirect current sampling circuit converts the differential voltage signal output by the current waveform reproduction circuit into a single-ended signal to ground, inputs the single-ended signal into a logic control module, and provides additional gain. The application can avoid the additional loss generated on the sampling resistor, and can realize the accurate sampling of the inductance current in a wide frequency range.

Description

Technical Field

[0001] This invention relates to a high-side current indirect sampling method based on the FSBB quasi-peak current control strategy, belonging to the field of current indirect sampling technology. Background Technology

[0002] The Four Switch Buck-Boost (FSBB) converter, as a power conversion topology with both boost and buck capabilities, can be used as a pre-regulator module in the power supply of high-performance computing chips such as GPUs and CPUs to cope with a wide range of input voltages and generate a 48V or 54V intermediate bus voltage.

[0003] The invention patent with patent application number 202211603927.5, entitled "Quasi-Peak Current Control Method for Four-Switch Buck-Boost Converter," discloses a quadrilateral current regulation method for an FSBB converter, such as... Figure 1 As shown, the method requires accurate sampling of the inductance in the FSBB converter. The current signal is input to the logic control module and finally modulated to produce the desired switching timing. Figure 1 The current sampling method using a ground wire series resistor is employed. Current and inductance flowing through Similarly, the voltage generated on it is amplified by the operational amplifier OA to produce a sampling signal in phase. However, this method has certain limitations. First, connecting a sampling resistor in series on the ground line changes the reference ground on the output side of the FSBB converter, increasing the design difficulty of the power switch drive circuit and auxiliary power supply of the rear bridge arm. Second, when multiple FSBB converters are connected in parallel, it is difficult to ensure that the current is shared across multiple ground lines, which will reduce the accuracy of current sampling for each phase. Finally, using resistor sampling introduces additional losses, and the power consumption limit of the sampling resistor itself will limit the improvement of FSBB power. In addition, existing high-potential side current sampling methods usually include: series sampling resistor combined with high-voltage operational amplifier and Hall current sensor. However, these two methods cannot simultaneously meet the requirements of chip voltage rating and sampling bandwidth. Operational amplifier chips with high bandwidth have low voltage ratings and are directly connected to inductors. The branch circuit may be damaged due to voltage spikes at the switching nodes. High-voltage operational amplifiers or Hall current sensors have low measurement bandwidth. Under the quasi-peak current control strategy, the switching frequency of the FSBB converter is usually in the megahertz range. Existing high-voltage operational amplifiers and Hall current sensors have bandwidths of only hundreds of kilohertz, so they cannot accurately reproduce the current waveform.

[0004] Patent application number 202310330810.2, entitled "A Lossless Sampling Method and Circuit for Inductor Current of a Four-Switch Buck-Buck Converter," discloses a method for current sampling using a reverse current mirror. The patent uses a transistor... With output capacitor When connected in parallel, the voltage of the transistor fluctuates significantly in a quadrilateral shape, and during operation, the transistor... The voltage waveform fluctuates less, while the transistor... The voltage waveform fluctuates widely with the output sampling signal, for example, 0-1.2V (the upper limit depends on the set amplification factor). When the voltage is close to 0, for example, less than 0.4V (the specific value depends on the transistor model), the transistor... and of When the voltage difference is large enough, the mirrored current will show a significant deviation, leading to waveform distortion. This distortion is related to changes in the transistor's operating region and the Earliest effect, a phenomenon unavoidable with transistors, and it becomes more pronounced as the operating frequency increases. Furthermore, in this patent, the current sampling signal starts changing from 0. The comparison threshold is close to 0, requiring a precise small voltage reference signal, which increases the design difficulty of the reference signal. Moreover, according to the inventor's paper "A High-Efficiency Control Method With Lossless Current Sensing and Seamless Transition for Four-Switch Buck–Boost Converter", the method is actually only implemented in the 300kHz-500kHz frequency range. Combined with the aforementioned distortion problem, the patented method is difficult to accurately replicate the current waveform at higher frequencies. Summary of the Invention

[0005] The purpose of this invention is to solve the problems existing in the prior art and to provide a high-side current indirect sampling method based on the FSBB quasi-peak current control strategy.

[0006] The objective of this invention is achieved through the following technical solution:

[0007] A high-side current indirect sampling method based on the FSBB quasi-peak current control strategy includes the following steps:

[0008] Step 1: Connect the input terminal of the indirect current sampling circuit to the midpoint of the front and rear bridge arms of the FSBB converter, respectively. The indirect current sampling circuit includes a current waveform reproduction circuit and an amplification circuit.

[0009] The current waveform reproduction circuit uses an operational amplifier and a transistor to form a voltage-controlled current source and a current mirror, which are used to control the capacitors in the current waveform reproduction circuit. and Controlled periodic constant current charging is performed. During the charging process, the capacitor... and voltage and With slope respectively and The current waveform is then recovered by differential signal processing, enabling accurate reproduction of the FSBB converter inductor current at megahertz frequencies. The input signal of the current waveform recovery circuit is the midpoint voltage between the front and rear arms of the FSBB converter. and The output signal is the capacitor. and Differential voltage signal on The current waveform reproduction circuit provides adjustable gain. ;

[0010] Step 2: The amplifier circuit outputs the differential voltage signal from the current waveform reproduction circuit in Step 1. Converted to a single-ended signal to ground. The input is fed into the logic control module of the FSBB quasi-peak current control strategy, where the amplifier circuit provides additional gain. And it is a single-ended signal output to ground. Provide the desired bias voltage .

[0011] Preferably, the current waveform reproduction circuit includes: a resistor operational amplifier NPN transistor PNP transistor ,capacitance and reset switch ;

[0012] resistance One end is connected to the midpoint of the front bridge arm of the FSBB converter, and the resistor... The other end is connected to the resistor. One end and op-amp Connect the non-inverting input terminal and the resistor. The other end is connected to the resistor. One end and reset switch One end is connected to and grounded, operational amplifier The inverting input terminals are respectively connected to the resistors The other end and the NPN transistor Emitter connection, op-amp Output terminal and NPN transistor Base connection, NPN transistor The collectors are respectively connected to the PNP type transistor. Collector, PNP transistor Base and PNP transistors Base connection, PNP type transistor Emitter and PNP transistor The emitter is connected to the power supply; it is a PNP transistor. The collectors are respectively connected to the capacitor. One end and reset switch The other end is connected to a capacitor. The other end is connected to the capacitor. One end is connected to and grounded, capacitor The other end is connected to the reset switch. One end and a PNP type transistor Collector connection, PNP type transistor Emitter and PNP transistor The emitter is connected to the power supply; it is a PNP transistor. The collectors are respectively connected to the PNP type transistor. Base, PNP type transistor Base and NPN transistor Collector connection, NPN transistor The emitter is connected to the resistor respectively One end and op-amp The inverting input is connected to an NPN transistor. Base and op-amp Output connection, op-amp The non-inverting input terminals are respectively connected to resistors One end and resistor One end connected, resistor The other end is connected to the midpoint of the rear bridge arm of the FSBB converter, and the resistor... The other end is connected to the resistor. The other end and the reset switch The other end is connected and grounded.

[0013] Preferably, the amplification circuit includes: a resistor and op-amps ;

[0014] capacitance The other end and the PNP transistor The connection between collectors and PNP transistors collector and capacitor The connection point between the two ends is the differential voltage of the current waveform reproduction circuit. Signal output terminal, resistor One end and resistor One end is connected to the differential voltage. Signal output connection, resistor The other end is connected to the resistor. One end and op-amp Inverting input terminal connected, resistor The other end and the op-amp The output terminal is connected, and the connection point is a single-ended signal to ground. Output terminal, resistor The other end is connected to the resistor. One end and op-amp Connect the non-inverting input terminal and the resistor. The other end is the bias voltage. Signal output terminal.

[0015] Preferably, the voltage mentioned in step one and slope and The formula is:

[0016]

[0017]

[0018] in, and Capacitors and Charging current, , For flow collector current, , For flow The collector current, and .

[0019] Preferably, the current waveform reproduction circuit described in step one provides adjustable gain. The formula is:

[0020]

[0021] in, For the inductor current of the FSBB converter, For capacitor and The capacitance value.

[0022] Preferably, the amplifier circuit described in step two provides additional gain. The formula is:

[0023] .

[0024] Preferably, the indirect current sampling circuit outputs a single-ended signal to ground. With inductor current The relation is:

[0025]

[0026] in, This represents the inductance value of the FSBB converter.

[0027] Preferably, the amplifier circuit can be configured as a voltage follower with differential input, a non-inverting amplifier, or a follower or non-inverting amplifier with bias voltage, as needed.

[0028] Preferably, the current waveform reproduction circuit includes a reset switch. Required reset signal and The falling edge of the waveform remains synchronized, corresponding to the switching device of the FSBB converter. Turn off, At the turn-on time, the output from the logic control module in the FSBB quasi-peak current control strategy is... The activation trigger signal serves as a reset signal.

[0029] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0030] This invention proposes a low-loss, high-precision, and high-bandwidth high-side current indirect sampling method based on the quasi-peak current control strategy of the FSBB converter. This method reconstructs the inductance by introducing the midpoint voltage of the two half-bridges of the FSBB converter. The current waveform can convert a large current signal into a small voltage signal, which is then input to the logic control module in the quasi-peak current control strategy to control the switch. Turn on / off according to the desired timing. Under the quasi-peak current control strategy based on the FSBB converter, the operating frequency of the FSBB converter varies widely, and the highest frequency is very high, reaching 400kHz-1400kHz. The method of this invention can achieve accurate sampling of inductor current over a wide frequency range.

[0031] Existing sampling methods using ground-connected series resistors introduce losses into the resistor. Typically, the sampling resistor has its own power consumption limit, which in turn limits the maximum current that can be transmitted through the inductor, thus limiting the maximum power that the FSBB converter can handle. Compared to the sampling method using ground-connected series resistors, the proposed indirect current sampling method eliminates the need for a sampling resistor. This avoids the additional losses generated by the sampling resistor and ensures that the maximum power that the FSBB converter can handle is not limited by the sampling resistor.

[0032] Existing high-potential-side current sampling methods typically include: a series sampling resistor combined with a high-voltage operational amplifier and a Hall current sensor. However, neither of these methods can simultaneously achieve both chip voltage withstand capability and sampling bandwidth. Operational amplifier chips with high bandwidth have lower voltage withstand capability and are directly connected to an inductor. The branch circuit may be damaged due to voltage spikes at the switching nodes. Operational amplifiers or Hall current sensors with high voltage withstand capability have low measurement bandwidths; high-voltage operational amplifiers and Hall current sensors have bandwidths of only a few hundred kilohertz, which cannot support accurate sampling over a wide range of 400kHz-1400kHz, especially above 500kHz. Compared to existing high-side current sampling chips, the method proposed in this invention has better voltage withstand characteristics and can reproduce inductor current waveforms at megahertz frequencies well.

[0033] Existing methods for current sampling using a reverse current mirror require a transistor in the pump current mirror. The voltage is a quadrilateral wave with a wide range of fluctuations, and the mirrored current will show significant deviations, leading to waveform distortion in the sampled waveform. However, the current mirror circuit in the current waveform reproduction circuit of this invention has smaller operating voltage fluctuations and is less affected by capacitor... and Controlled periodic constant current charging is performed; during the charging process, the capacitor... and voltage and With slope respectively and The waveform rises, and then the reproducible waveform is obtained through signal differential, avoiding capacitance. and Connected directly in parallel across the transistor on the output side of the current mirror, thus reducing capacitance. and Large voltage changes and For transistors , The impact of the work area can be avoided. The problem of transistor amplification factor mismatch caused by large voltage fluctuations in the current mirror circuit is solved by reducing the asymmetry of the current mirror circuit, thereby reducing the distortion of the sampled waveform, making the sampled waveform clearer at the inflection point and closer to the target current signal, and can be applied to higher operating frequencies.

[0034] This invention converts differential signals into single-ended signals through an amplifier circuit, providing the possibility of increasing the sampling bias voltage. Furthermore, the amplifier circuit can be configured as either a follower or a proportional amplifier, offering greater flexibility in the gain configuration of the indirect current sampling circuit. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of a circuit for current sampling using a ground wire series resistor.

[0036] Figure 2 This is a circuit diagram of high-side current indirect sampling based on the FSBB quasi-peak current control strategy of the present invention.

[0037] Figure 3 This is a schematic diagram of a circuit for reproducing current waveforms.

[0038] Figure 4 This is a schematic diagram of the key waveforms in the current waveform reproduction circuit.

[0039] Figure 5 A schematic diagram of the quasi-peak current logic control module.

[0040] Figure 6 This is a schematic diagram of a typical operational amplifier (OA) configuration.

[0041] Figure 7 This is a schematic diagram of the SPICE simulation model; where:

[0042] Figure 7 (a) is a schematic diagram of the current waveform reproduction circuit;

[0043] Figure 7 (b) is a schematic diagram of the bias voltage generation circuit;

[0044] Figure 7 (c) is a schematic diagram of a follower with bias;

[0045] Figure 7 (d) is a schematic diagram of the reset switch drive circuit.

[0046] Figure 8 This is a schematic diagram of the test waveform under light load and reduced voltage conditions.

[0047] Figure 9 This is a schematic diagram of the test waveform under heavy load and boost voltage conditions. Detailed Implementation

[0048] The present invention will be further described in detail below with reference to the accompanying drawings: This embodiment is implemented under the premise of the technical solution of the present invention, and detailed implementation methods are given, but the protection scope of the present invention is not limited to the following embodiments.

[0049] like Figure 2 As shown, the indirect current sampling method for high-side current based on the FSBB quasi-peak current control strategy in this embodiment includes: a current waveform reconstruction circuit and an amplification circuit. The two inputs of the current waveform reconstruction circuit are the voltage signal at the midpoint A of the front bridge arm. and the voltage signal at the midpoint B of the rear axle arm It outputs a differential voltage signal. This signal is related to the inductor current signal. They are in phase and have a proportional relationship, that is... .

[0050] Operational amplifiers (OAs) mainly have the following three functions:

[0051] 1) Convert the differential voltage signal Converted to a single-ended signal to ground. And input it to the logic control module;

[0052] 2) Provides additional gain ,Right now ;

[0053] 3) Single-ended signal as needed. Provides bias voltage.

[0054] Current waveform reproduction circuit, such as Figure 3 As shown, it mainly includes: resistors operational amplifier NPN transistor PNP transistor ,capacitance and reset switch The circuit structure is symmetrical from left to right. Taking the side as an example, the resistor and The voltage at the midpoint of the front axle arm can be increased. Voltage divider to operational amplifier Within the required operating voltage range. Operational amplifier. NPN transistor and resistance This forms a voltage-controlled current source, flowing through collector current It can be expressed by equation (1) when Once the resistance value is determined, its current amplitude is only affected by... Regulation, PNP transistor and The current mirror structure can be constructed to reflect current. Replicate and generate current , to capacitor Controlled constant current charging is performed to generate voltage. And there are . Similarly, resistance and The voltage at the midpoint of the front axle arm can be increased. Voltage divider to operational amplifier Within the required operating voltage range. Operational amplifier. NPN transistor and resistance This forms a voltage-controlled current source, flowing through collector current It can be expressed by equation (2) when Once the resistance value is determined, its current amplitude is only affected by... Regulation, PNP transistor and The current mirror structure can be constructed to reflect current. Replicate and generate current , to capacitor Controlled constant current charging is performed to generate voltage. And there are Differential output voltage It is given by equation (3).

[0055] (1)

[0056] (2)

[0057] (3)

[0058] Under the quasi-peak current control strategy, the midpoint voltage of the two arms of the FSBB and For square waves with variable amplitude, pulse width, and period, such as Figure 4 As shown in the figure, the FSBB inductor current is given, representing two operating conditions: light load & boost and heavy load & buck. Midpoint voltage of the two bridge arms and Charging current and ,capacitance , Voltage and Differential output voltage and reset signal A waveform diagram.

[0059] When under light load and boost conditions, the inductor current It is in an intermittent state, and has Amplitude greater than When taking , , and Then, according to (1) and (2), we have (4), correspondingly ,exist Figure 2 switch Open, When shut down, High level, current To capacitor Constant current charging, the latter voltage With slope Rise, among which Represented by (5). When the switch... Turn off, When it is activated, Low level, current Stop feeding the capacitor Constant current charging, Hold until the reset signal arrives, switch Open, Reset to 0. (At the switch) Open, When shut down, High level, current To capacitor Constant current charging, the latter voltage With slope Rise, among which (6) indicates that when the switch... Turn off, When it is activated, When it goes low, the current Stop feeding the capacitor Constant current charging, reset signal arrives, switch Open, Reset to 0. After reset, and All remain at 0 until the next time. and Once it goes high, the cycle repeats.

[0060] (4)

[0061] (5)

[0062] (6)

[0063] When under heavy load and step-down conditions, the inductor current It is in a continuous state and has Amplitude less than Accordingly ,exist When it is high level, the current To capacitor Constant current charging, the latter voltage With slope Rise, when When it is low level, the current Stop feeding the capacitor Constant current charging, Hold until the reset signal arrives, switch Open, Reset to 0. When it is high level, the current To capacitor Constant current charging, the latter voltage With slope Rise, when When it goes low, the current Stop feeding the capacitor Constant current charging, reset signal arrives, switch Open, Reset to 0. After reset, and All remain at 0 until the next time. and Once it goes high, the cycle repeats.

[0064] From the above analysis, it can be seen that, according to the relationships in equations (4) to (6), in and During the stage where the voltage is not zero, Inductor current can be reproduced proportionally. The changing waveform, in and The stage where the voltage is 0. Keeping it at 0 allows the inductor current to be reproduced. Discontinuous waveform. When the inductor current... When continuous, , and It can also reset and start the next cycle in a short time, where the reset signal and... The falling edges of the waveform remain synchronized. In summary, this can be achieved using equation... Give With inductor current The relationship, i.e., the gain provided by the current waveform reproduction circuit. ,in For FSBB inductance value, For capacitor and The capacitance value. When the FSBB design is completed... The resistance remains constant, therefore it can be adjusted by changing the resistance. and Adjust the value to control the gain .

[0065] (7)

[0066] Furthermore, based on the above analysis, the reset signal and The falling edges of the waveform remain synchronized, and their corresponding Turn off, Opening time, therefore, as Figure 5 As shown, the output from the quasi-peak current logic control module is... The activation trigger signal serves as a reset signal.

[0067] In the proposed indirect current sampling method, the operational amplifier OA can be constructed as a voltage follower with differential input, a non-inverting amplifier, or a follower / non-inverting amplifier with bias voltage, as needed. For example... Figure 6 As shown, the input of op-amp A3 is a differential voltage. The output is a ground signal. , This is the bias voltage, which typically includes a resistor. , The gain it can provide Therefore, the FSBB indirect current sampling method proposed in this invention ultimately outputs... The signal is derived from the formula Give

[0068] (8)

[0069] Example 1

[0070] A high-side current indirect sampling method based on a quasi-peak current control strategy of FSBB was proposed. Circuit simulation based on the SPICE model was performed to verify the effectiveness of the invention. Figure 7 As shown, the simulation circuit includes Figure 7 (a) Current waveform reproduction circuit Figure 7 (b) Bias voltage generating circuit Figure 7 (c) Differential-to-single-ended voltage follower with bias and Figure 7 (d) Reset switch drive circuit; key component selection is given in Table 1. Additionally, resistors... , , , ,capacitance FSBB inductor Bias voltage Therefore, the gain provided by the current waveform reproduction circuit... The gain provided by the differential to single-ended voltage follower The total gain is approximately 0.033.

[0071] Figure 8 The test results of key waveforms under light load and buck operating conditions are shown. Under these conditions, the FSBB converter has an input voltage of 60V, an output voltage of 54V, a load current of 0.86A, and an operating frequency of 1.4MHz. The waveforms show... The inductor current was reproduced well. The shape, and according to the measurement The peak-to-peak value is 9.65A. The peak-to-peak value is 0.31V, with a 1V bias and a gain of 0.032, which is close to the theoretical design value mentioned above. Furthermore, , , , , and The waveforms are all the same as Figure 4 The theoretical analysis is consistent.

[0072] Table 1 Key Component Selection Table

[0073]

[0074] like Figure 9 The image shows the test results of key waveforms under heavy load and boost conditions. At this time, the FSBB converter has an input voltage of 40V, an output voltage of 54V, a load current of 8.6A, and an operating frequency of 1.0MHz. The waveforms show... The inductor current was reproduced well. The shape. According to measurements, The peak-to-peak value is 27.16A. The peak-to-peak value is 0.99V, with a 1V bias and a gain of 0.036, which is close to the theoretical design value mentioned above. Furthermore, , , , , and The waveforms are all the same as Figure 4 The theoretical analysis is consistent.

[0075] In summary, this invention proposes an indirect current sampling method based on the FSBB quasi-peak current control strategy, which can accurately reproduce the inductor current waveform of the FSBB converter in boost, buck, continuous current and discontinuous current operating modes at a megahertz operating frequency.

[0076] The above description is merely a preferred embodiment of the present invention. These specific embodiments are different implementations based on the overall concept of the present invention, and the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A high-side current indirect sampling method based on FSBB quasi-peak current control strategy, characterized in that, Includes the following steps: Step 1: Connect the input terminal of the indirect current sampling circuit to the midpoint of the front and rear bridge arms of the FSBB converter, respectively. The indirect current sampling circuit includes a current waveform reproduction circuit and an amplification circuit. The current waveform reproduction circuit includes: a resistor , an operational amplifier , an NPN-type transistor , a PNP-type transistor , a capacitor , and a reset switch ; resistance One end is connected to the midpoint of the front bridge arm of the FSBB converter, and the resistor... The other end is connected to the resistor. One end and op-amp Connect the non-inverting input terminal and the resistor. The other end is connected to the resistor. One end and reset switch One end is connected to and grounded, operational amplifier The inverting input terminals are respectively connected to the resistors The other end and the NPN transistor Emitter connection, op-amp Output terminal and NPN transistor Base connection, NPN transistor The collectors are respectively connected to the PNP type transistor. Collector, PNP transistor Base and PNP transistors Base connection, PNP type transistor Emitter and PNP transistor The emitter is connected to the power supply; it is a PNP transistor. The collectors are respectively connected to the capacitor. One end and reset switch The other end is connected to a capacitor. The other end is connected to the capacitor. One end is connected to and grounded, capacitor The other end is connected to the reset switch. One end and a PNP type transistor Collector connection, PNP type transistor Emitter and PNP transistor The emitter is connected to the power supply; it is a PNP transistor. The collectors are respectively connected to the PNP type transistor. Base, PNP type transistor Base and NPN transistor Collector connection, NPN transistor The emitter and resistor are respectively One end and op-amp The inverting input is connected to an NPN transistor. Base and op-amp Output connection, op-amp The non-inverting input terminals are respectively connected to resistors One end and resistor One end connected, resistor The other end is connected to the midpoint of the rear bridge arm of the FSBB converter, and the resistor... The other end is connected to the resistor. The other end and the reset switch The other end is connected and grounded; The amplifier circuit includes: a resistor and op-amps ; capacitance The other end and the PNP transistor The connection between collectors and PNP transistors collector and capacitor The connection point between the two ends is the differential voltage of the current waveform reproduction circuit. Signal output terminal, resistor One end and resistor One end is connected to the differential voltage. Signal output connection, resistor The other end is connected to the resistor. One end and op-amp Inverting input terminal connected, resistor The other end and the op-amp The output terminal is connected, and the connection point is a single-ended signal to ground. Output terminal, resistor The other end is connected to the resistor. One end and op-amp Connect the non-inverting input terminal and the resistor. The other end is the bias voltage. Signal output terminal; the current waveform reproduction circuit uses operational amplifiers and transistors to form a voltage-controlled current source and a current mirror, which affects the capacitors in the current waveform reproduction circuit. and Controlled periodic constant current charging is performed. During the charging process, the capacitor... and voltage and With slope respectively and The current waveform is then recovered by differential signal processing, enabling accurate reproduction of the FSBB converter inductor current at megahertz frequencies. The input signal of the current waveform recovery circuit is the midpoint voltage between the front and rear arms of the FSBB converter. and The output signal is the capacitor. and Differential voltage signal on The current waveform reproduction circuit provides adjustable gain. ; Step 2: The amplifier circuit outputs the differential voltage signal from the current waveform reproduction circuit in Step 1. Converted to a single-ended signal to ground. The input is fed into the logic control module of the FSBB quasi-peak current control strategy, where the amplifier circuit provides additional gain. And it is a single-ended signal output to ground. Provide the desired bias voltage .

2. The high-side current indirect sampling method based on the FSBB quasi-peak current control strategy according to claim 1, characterized in that, The voltage mentioned in step one and slope and The formula is: in, and Capacitors and Charging current, , For flow collector current, , For flow The collector current, and .

3. The high-side current indirect sampling method based on the FSBB quasi-peak current control strategy according to claim 2, characterized in that, The current waveform reproduction circuit described in step one provides adjustable gain. The formula is: in, For the inductor current of the FSBB converter, For capacitor and The capacitance value.

4. The high-side current indirect sampling method based on the FSBB quasi-peak current control strategy according to claim 3, characterized in that, The amplifier circuit described in step two provides additional gain. The formula is: 。 5. The high-side current indirect sampling method based on the FSBB quasi-peak current control strategy according to claim 4, characterized in that, The single-ended signal to ground output by the indirect current sampling circuit With inductor current The relation is: in, This represents the inductance value of the FSBB converter.

6. The high-side current indirect sampling method based on the FSBB quasi-peak current control strategy according to claim 1, characterized in that, The amplifier circuit can be configured as a voltage follower with differential input, a non-inverting amplifier, or a follower or non-inverting amplifier with bias voltage, as needed.

7. The high-side current indirect sampling method based on the FSBB quasi-peak current control strategy according to claim 1, characterized in that, The reset switch in the current waveform reproduction circuit Required reset signal and The falling edge of the waveform remains synchronized, corresponding to the switching device of the FSBB converter. Turn off, Opening time, , These are the upper and lower switches of the rear bridge arm of the FSBB converter, respectively, and are output from the logic control module in the FSBB quasi-peak current control strategy. The activation trigger signal serves as a reset signal.

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