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CN-122001183-A - High-side current indirect sampling method based on FSBB quasi-peak current control strategy

CN122001183ACN 122001183 ACN122001183 ACN 122001183ACN-122001183-A

Abstract

The invention provides a high-side current indirect sampling method based on FSBB quasi-peak current control strategy, and belongs to the technical field of current indirect sampling. The invention comprises the following steps of connecting an indirect current sampling circuit with a FSBB converter, enabling a current waveform reproduction circuit of the indirect current sampling circuit to form a voltage-controlled current source and a current mirror through an operational amplifier and a triode, carrying out controllable periodic constant-current charging on a capacitor, enabling the voltage of the capacitor to rise in a fixed slope in the charging process, reproducing the sampling waveform in a signal differential mode, realizing accurate reproduction of inductance current at megahertz frequency and providing adjustable gain, and secondly, enabling an amplifying circuit of the indirect current sampling circuit to convert a differential voltage signal output by the current waveform reproduction circuit into a single-ended signal to the ground, inputting the single-ended signal into a logic control module and providing additional gain. The invention can avoid extra loss generated on the sampling resistor and can realize accurate sampling of the inductance current in a wide frequency range.

Inventors

  • XU DIANGUO
  • Wen Zhaoliang
  • ZHENG JINGHAO

Assignees

  • 哈尔滨工业大学

Dates

Publication Date
20260508
Application Date
20260119

Claims (9)

  1. 1. A high-side current indirect sampling method based on FSBB quasi-peak current control strategy is characterized by comprising the following steps: The method comprises the steps that an input end of an indirect current sampling circuit is connected with midpoints of a front bridge arm and a rear bridge arm of a FSBB converter respectively, wherein the indirect current sampling circuit comprises a current waveform reproduction circuit and an amplifying circuit; The current waveform reproduction circuit forms a voltage-controlled current source and a current mirror through an operational amplifier and a triode, and is used for capacitance in the current waveform reproduction circuit And Controllable periodic constant current charging is carried out, and in the charging process, a capacitor is used for charging And Voltage of (2) And Respectively with slopes And Rising, reproducing the current waveform in a signal difference mode, and realizing accurate reproduction of the inductor current of the FSBB converter under the megahertz frequency, wherein the input signal of the current waveform reproduction circuit is the midpoint voltage between the front bridge arm and the rear bridge arm of the FSBB converter And The output signal is the capacitor And Differential voltage signal on The current waveform reproduction circuit provides an adjustable gain ; Step two, the amplifying circuit reproduces the differential voltage signal output by the circuit in step one Conversion to single-ended signals to ground Inputting it into logic control module in FSBB quasi-peak current control strategy, and providing additional gain by amplifying circuit And is outputting a single-ended signal to ground Providing a desired bias voltage 。
  2. 2. The method for indirectly sampling high-side current based on FSBB quasi-peak current control strategy according to claim 1, wherein the current waveform reproduction circuit comprises a resistor Operational amplifier NPN type triode PNP type triode Capacitance, capacitance Reset switch ; Resistor One end is connected with the midpoint of the front bridge arm of the FSBB converter, and the resistor The other end is respectively connected with the resistor One end and an operational amplifier The non-inverting input end is connected with the resistor The other end is respectively connected with the resistor One end and reset switch One end is connected with the ground, and the operational amplifier The inverting input ends are respectively connected with the resistor Another end and NPN triode Emitter connection, op-amp Output terminal and NPN triode Base electrode connection NPN triode Collector and PNP triode respectively Collector and PNP type triode Base and PNP type triode Base is connected, PNP type triode Emitter and PNP triode The emitter is connected with a power supply, and the PNP triode Collector electrodes and capacitors respectively One end and reset switch The other end is connected with a capacitor The other end and the capacitor One end of the capacitor is connected with the ground The other end is respectively connected with a reset switch One end and PNP type triode Collector connection, PNP triode Emitter and PNP triode The emitter is connected with a power supply, and the PNP triode Collector and PNP triode respectively Base and PNP type triode Base and NPN triode Collector connection NPN triode Emitter and resistor respectively One end and an operational amplifier The inverting input end is connected with NPN triode Base and operational amplifier The output end is connected with the operational amplifier The non-inverting input ends are respectively connected with the resistor One end and resistor One end is connected with the resistor The other end is connected with the midpoint of the back bridge arm of the FSBB converter, and the resistor The other end is respectively connected with the resistor Another end and reset switch The other end is connected with the ground.
  3. 3. The method for indirectly sampling high-side current based on FSBB quasi-peak current control strategy according to claim 2, wherein the amplifying circuit comprises a resistor Operational amplifier ; Capacitance device Another end and PNP triode Junction between collector electrodes and PNP type triode Collector and capacitor Differential voltage with current waveform reproduction circuit at the junction between one ends Signal output terminal, resistor One end and resistor One end is respectively connected with differential voltage The signal output end is connected with the resistor The other end is respectively connected with the resistor One end and an operational amplifier The inverting input terminal is connected with the resistor Another end and operational amplifier The output end is connected with the single-ended signal which is grounded at the connection part Output terminal, resistor The other end is respectively connected with the resistor One end and an operational amplifier The non-inverting input end is connected with the resistor The other end is biased with voltage And a signal output terminal.
  4. 4. A method for indirectly sampling a high-side current based on a FSBB quasi-peak current control strategy according to claim 3, wherein said voltage in step one And Slope of (2) And The formula of (2) is: Wherein, the And Respectively, capacitors And The charge current is applied to the battery by a voltage source, , For flowing through The current of the collector electrode is such that, , For flowing through Current of collector, and 。
  5. 5. A high side current indirect sampling method based on FSBB quasi-peak current control strategy according to claim 3, wherein in step one said current waveform reproduction circuit provides adjustable gain The formula of (2) is: Wherein, the For the FSBB transformer inductor current, Is a capacitor And Is a capacitance value of (2).
  6. 6. The method for indirect sampling of high-side current based on FSBB quasi-peak current control strategy as claimed in claim 5, wherein said amplifying circuit provides additional gain in step two The formula of (2) is: 。
  7. 7. the method for indirect sampling of high-side current based on FSBB quasi-peak current control strategy as set forth in claim 6, wherein said indirect current sampling circuit outputs a single-ended signal to ground And inductor current The relation of (2) is: Wherein, the Is FSBB the converter inductance value.
  8. 8. The method of claim 1, wherein the amplifying circuit can be configured as a voltage follower with differential input, an in-phase proportional amplifier, or a follower with bias voltage or an in-phase proportional amplifier, as required.
  9. 9. The method for indirectly sampling high-side current based on FSBB quasi-peak current control strategy according to claim 1, wherein the reset switch in the current waveform reproduction circuit Required reset signal And (3) with The falling edges of the waveforms remain synchronized, which corresponds to FSBB inverter switching devices The switch-off is performed and the switch-off is performed, The starting time is output by a logic control module in FSBB quasi-peak current control strategy The turn-on trigger signal serves as a reset signal.

Description

High-side current indirect sampling method based on FSBB quasi-peak current control strategy Technical Field The invention relates to a high-side current indirect sampling method based on FSBB quasi-peak current control strategy, and belongs to the technical field of current indirect sampling. Background The four-switch Buck-Boost converter (Four Switch Buck-Boost, FSBB) is used as an electric energy conversion topology with boosting and reducing capabilities, can be used as a pre-voltage stabilizing module to cope with wider input voltage in power supply of high-performance computing chips such as a GPU (graphic processing unit), a CPU (Central processing Unit) and the like, and can generate 48V or 54V middle bus voltage. Patent application number 202211603927.5, entitled "quasi-peak current control method for four-switch Buck-Boost converter", discloses a quadrilateral current regulation method for FSBB converter, which requires accurate sampling of the inductance in FSBB converter, as shown in FIG. 1The current signal is input to a logic control module, and finally the expected switching time sequence is modulated. In FIG. 1, a current sampling method of a ground wire series resistor is adopted, and the resistorCurrent and inductance flowing upwardsThe same voltage is amplified by the operational amplifier OA to generate the same phase sampling signal. However, the method has certain limitations, firstly, a sampling resistor is connected in series with the ground wire to change the reference ground of the output side of the FSBB converter, the design difficulty of a rear bridge arm power switch driving circuit and an auxiliary power supply is increased, secondly, when a plurality of FSBB converters are connected in parallel, the current sharing of the ground wires is difficult to ensure, the accuracy of current sampling of each phase is reduced, finally, extra loss is introduced by using the resistor sampling, and the upper limit of the power consumption of the sampling resistor can limit the improvement of FSBB power. In addition, the existing high-potential side current sampling method generally comprises the steps of connecting a sampling resistor in series and combining a high-voltage-resistant operational amplifier and a Hall current sensor, wherein the two methods cannot be compatible with chip voltage resistance and sampling bandwidth, an operational amplifier chip with higher bandwidth is low in voltage resistance and directly connected into an inductorThe high withstand voltage operational amplifier or the Hall current sensor has low measurement bandwidth, and under the quasi-peak current control strategy, the switching frequency of the FSBB converter is usually megahertz, and the bandwidth of the existing high withstand voltage operational amplifier and the bandwidth of the Hall current sensor are only hundred kilohertz, so that the current waveform cannot be accurately re-carved. The patent application number 202310330810.2 is a non-destructive sampling method and circuit for inductor current of four-switch buck-boost converter, in which a method for sampling current by adopting reverse current mirror mode is disclosed, and the patent name is a triodeAnd output capacitanceIn parallel, the voltage is a quadrilateral wave with large fluctuation, and in operation, the triodeIs small in voltage waveform fluctuation, and triodeThe voltage waveform of (a) fluctuates widely with the output sampling signal, such as 0-1.2V (upper limit is related to the set amplification), and when the voltage approaches 0, such as less than 0.4V (specific value is related to the triode model), the triodeAnd (3) withA kind of electronic deviceThe voltage difference is large enough, the mirror current can have obvious deviation, so that the sampling waveform is distorted, the distortion is related to the change of the triode working area and the early effect, the phenomenon cannot be avoided by the triode, and the phenomenon is more prominent with the increase of the working frequency. In addition, the current sampling signal in this patent varies from 0,The comparison threshold is close to 0, an accurate small voltage reference signal needs to be provided, the design difficulty of the reference signal is increased, and the paper "A High-Efficiency Control Method With Lossless Current Sensing and Seamless Transition for Four-Switch Buck–Boost Converter", of the patent inventor shows that the method is actually only implemented in the frequency range of 300kHz-500kHz, and the method is difficult to accurately copy the current waveform at higher frequency in combination with the distortion problem. Disclosure of Invention The invention aims to solve the problems in the prior art, and further provides a high-side current indirect sampling method based on FSBB quasi-peak current control strategy. The invention aims at realizing the following technical scheme: A high-side current indirect sampling method based on FSBB quasi-