WO2022110205A1 - 一种电压转换电路、电压转换器及电子设备 - Google Patents

一种电压转换电路、电压转换器及电子设备 Download PDF

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Publication number
WO2022110205A1
WO2022110205A1 PCT/CN2020/132919 CN2020132919W WO2022110205A1 WO 2022110205 A1 WO2022110205 A1 WO 2022110205A1 CN 2020132919 W CN2020132919 W CN 2020132919W WO 2022110205 A1 WO2022110205 A1 WO 2022110205A1
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Prior art keywords
circuit
voltage
buck
detection
detection resistor
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PCT/CN2020/132919
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English (en)
French (fr)
Inventor
李文广
吕泽杰
柯玉连
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华为数字能源技术有限公司
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Priority to PCT/CN2020/132919 priority Critical patent/WO2022110205A1/zh
Priority to CN202080018137.3A priority patent/CN114846338A/zh
Priority to EP20963093.8A priority patent/EP4220197A4/en
Publication of WO2022110205A1 publication Critical patent/WO2022110205A1/zh
Priority to US18/325,946 priority patent/US20230327560A1/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
    • G01R19/25—Arrangements for measuring currents or voltages or for indicating presence or sign thereof using digital measurement techniques
    • G01R19/2506—Arrangements for conditioning or analysing measured signals, e.g. for indicating peak values ; Details concerning sampling, digitizing or waveform capturing
    • G01R19/2509—Details concerning sampling, digitizing or waveform capturing
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
    • G01R19/04—Measuring peak values or amplitude or envelope of ac or of pulses
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/0003—Details of control, feedback or regulation circuits
    • H02M1/0009—Devices or circuits for detecting current in a converter
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/32—Means for protecting converters other than automatic disconnection
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
    • H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
    • H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
    • H02M3/158—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load
    • H02M3/1582—Buck-boost converters

Definitions

  • the present application relates to the technical field of voltage converters, and in particular, to a voltage conversion circuit, a voltage converter and an electronic device.
  • Buck-Boost (Buck-Boost) circuit is a common DC-DC voltage (current) conversion circuit, which is often used in voltage converters in various types of power systems.
  • voltage converters in power systems such as power management systems for electric/hybrid vehicles, photovoltaic power generation systems, and communication power supply systems all need to use Buck-Boost circuits to achieve voltage conversion.
  • a Buck-Boost circuit mainly includes multiple switches and inductors. By changing the on and off of each switch, the charge and discharge states of the inductors in the Buck-Boost circuit can be controlled, thereby realizing voltage conversion.
  • the voltage converter can monitor the working state of the Buck-Boost circuit according to the inductor current in the Buck-Boost circuit.
  • the voltage converter can also perform over current protection according to the inductor current in the Buck-Boost circuit. OCP), etc.
  • a current sensor in series with the inductor can be added to the Buck-Boost circuit.
  • the current sensor can detect the inductor current flowing through the inductor and output a current detection signal to indicate the current inductor. the magnitude of the current.
  • the high cost of current sensors is not conducive to cost savings.
  • the detection delay of the current sensor is relatively large, which limits the application range of the detection result.
  • the present application provides a voltage conversion circuit, a voltage converter and an electronic device, which can detect the inductor current in the voltage conversion circuit, and at the same time help to reduce the detection cost of the inductor current, and also help to reduce the detection delay of the inductor current.
  • an embodiment of the present application provides a voltage conversion circuit, which mainly includes a detection circuit having a first detection resistor and a second detection resistor, and a Buck-Boost circuit with an H-bridge structure.
  • the Buck-Boost circuit includes a first bridge arm, a second bridge arm, and an inductor, the inductor is located between the first bridge arm and the second bridge arm, and two ends of the first bridge arm are respectively connected to two ends of the second bridge arm.
  • the terminals are connected one by one.
  • One end of the first bridge arm is connected to one input end of the Buck-Boost circuit through the first detection resistor, and the other end of the first bridge arm is connected to the other input end of the Buck-Boost circuit.
  • One end of the second bridge arm is connected to one output end of the Buck-Boost circuit through the second detection resistor, and the other end of the second bridge arm is connected to the other output end of the Buck-Boost circuit.
  • the detection circuit can respectively perform voltage sampling on the first resistance voltage of the first detection resistance and the second resistance voltage of the second detection resistance, and then the detection circuit can output a current detection signal according to the maximum voltage of the first resistance voltage and the second resistance voltage , wherein the maximum voltage of the first resistor voltage and the second resistor voltage is the voltage of the detection resistor through which the inductor current of the inductor passes, and the current detection signal is used to indicate the magnitude of the inductor current.
  • the inductor current can flow through the first detection resistor and the second detection resistor, and at this time, the first resistor voltage and the second resistor voltage are both maximum voltages.
  • the inductor current In the inductor freewheeling stage of Buck-Boost circuit step-down conversion, the inductor current only flows through the second detection resistor, and does not flow through the first detection resistor, and the voltage of the second resistor is the maximum voltage at this time.
  • the inductor current can flow through the first detection resistor, but not through the second detection resistor, and the voltage of the first resistor is the maximum voltage at this time.
  • the inductor freewheeling stage of the boost conversion of the Buck-Boost circuit the inductor current can flow through the first detection resistor and the second detection resistor, and at this time, the first resistor voltage and the second resistor voltage are both maximum voltages.
  • the Buck-Boost circuit performs boost conversion or buck conversion, there is at least one detection resistor in the first detection resistor and the second detection resistor that can transmit the inductor current. Therefore, the detection circuit can transmit the inductor current according to the first resistor voltage and The maximum voltage among the second resistor voltages outputs the current detection signal, so that the current detection signal can indicate the magnitude of the inductor current.
  • one end of the first detection resistor may be connected to the high-potential input terminal of the Buck-Boost circuit, or may be connected to the low-potential input terminal of the Buck-Boost circuit.
  • One end of the second detection resistor may be connected to the high-potential output terminal of the Buck-Boost circuit, or may be connected to the low-potential output terminal of the Buck-Boost circuit. This embodiment of the present application does not limit this.
  • one end of the first detection resistor when one end of the first detection resistor is connected to the low potential input end of the Buck-Boost circuit, one end of the first bridge arm is connected to the low potential input end of the Buck-Boost circuit through the first detection resistor, and the first bridge arm is connected to the low potential input end of the Buck-Boost circuit through the first detection resistor. The other end is connected to the high potential input of the Buck-Boost circuit.
  • one end of the second bridge arm is connected to the low potential output end of the Buck-Boost circuit through the second detection resistor, the other end of the second bridge arm is connected to the high potential output end of the Buck-Boost circuit.
  • the potential across the first detection resistor and the potential across the second detection resistor are relatively low, and the common-mode voltage (voltage to ground) across the two detection resistors is relatively low, which is beneficial to improve the detection circuit's resistance to the resistor voltage. Sampling accuracy.
  • the Buck-Boost circuit may further include an input capacitor, and the input capacitor can filter the input voltage of the Buck-Boost circuit.
  • one end of the input capacitor is connected to the high-potential input end of the Buck-Boost circuit, the other end of the input capacitor is connected to the low-potential input end of the Buck-Boost circuit, and the first detection resistor is located between the input capacitor and the first between the bridge arms.
  • the input capacitor has the function of filtering, if the first detection resistor is located between the low potential input terminal of the Buck-Boost circuit and the input capacitor, that is, the input capacitor passes through the first detection resistor and the low potential of the Buck-Boost circuit. If the input terminal is connected, the current passing through the first detection resistor will be the average current of the inductor current, which is not conducive to detecting the real-time inductor current.
  • the filtering effect of the input capacitor does not affect the current through the first detection resistor, that is, the current through the first detection resistor can be real-time Inductor current, therefore, it is beneficial to detect the real-time inductor current through the resistance voltage of the first detection resistor.
  • the Buck-Boost circuit may further include an output capacitor, one end of the output capacitor is connected to the high-potential output end of the Buck-Boost circuit, the other end of the output capacitor is connected to the low-potential output end of the Buck-Boost circuit, and the second detection resistor. between the output capacitor and the second bridge leg.
  • the detection circuit is further exemplified.
  • the detection circuit may further include a first sampling circuit, a second sampling circuit, and a combining circuit, wherein the first sampling circuit is respectively connected to both ends of the first detection resistor and the combining circuit, and the second sampling circuit is respectively connected to Both ends of the second detection resistor are connected to the combining circuit.
  • the first sampling circuit can output a first sampling signal to the combining circuit according to the first resistance voltage of the first detection resistor, and the voltage of the first sampling signal and the first resistance voltage satisfy a positive correlation;
  • the second sampling circuit The second sampling signal can be output to the combining circuit according to the second resistance voltage of the second detection resistor, and the voltage of the second sampling signal and the second resistance voltage satisfy a positive correlation;
  • the combining circuit can be based on the first sampling signal and the maximum voltage in the second sampling signal to output the current detection signal.
  • the same positive correlation should be satisfied between the first sampling signal and the first resistor voltage, and between the second sampling signal and the second resistor voltage, so as to ensure that the first sampling signal and the second By sampling the signal, the relative magnitude relationship between the first resistor voltage and the second resistor voltage can be determined.
  • the first sampling circuit may include a first operational amplifier circuit, one input terminal of the first operational amplifier circuit is connected to one end of the first detection resistor, and the other input terminal of the first operational amplifier circuit is connected to the first detection resistor. is connected to the other end of the first operational amplifier circuit, and the output end of the first operational amplifier circuit is used to output the first sampling signal.
  • the voltage of the first sampled signal is positive. Therefore, the forward input terminal of the first operational amplifier circuit can be connected to the high potential terminal of the first detection resistor, and the reverse input terminal of the first operational amplifier circuit can be connected to the low potential terminal of the first detection resistor.
  • the second sampling circuit may include a second operational amplifier circuit, one input terminal of the second operational amplifier circuit is connected to one end of the second detection resistor, and the other input terminal of the second operational amplifier circuit is connected to the second detection resistor. is connected to the other end of the second operational amplifier circuit, and the output end of the second operational amplifier circuit is used to output the second sampling signal.
  • the voltage of the second sampling signal is positive. Therefore, the forward input terminal of the second operational amplifier circuit can be connected to the high potential terminal of the second detection resistor, and the reverse input terminal of the second operational amplifier circuit can be connected to the low potential terminal of the second detection resistor.
  • the combining circuit may include a first diode and a second diode, wherein the anode of the first diode is connected to the first sampling circuit, and the anode of the second diode is connected to the second sampling circuit , the cathode of the first diode and the cathode of the second diode are connected through a first connection point, and the first connection point can output a current detection signal.
  • the diode with the larger anode voltage will turn off the diode with the lower anode voltage.
  • the anode voltage of the first diode is the voltage of the first sampling signal
  • the anode voltage of the second diode is the voltage of the second sampling signal. Therefore, when the voltage of the first sampling signal is greater than the voltage of the second sampling signal, the first diode is turned on, so that the voltage of the first connection point is the voltage of the first sampling signal. Similarly, when the voltage of the second sampling signal is greater than the voltage of the first sampling signal, the second diode is turned on, so that the voltage of the first connection point is the voltage of the second sampling signal.
  • the voltage of the first sampling point is the larger voltage among the first sampling signal and the second sampling signal, and there is a relationship between the first sampling signal and the second sampling signal and the first resistance voltage and the second resistance voltage respectively Therefore, there is a positive correlation between the larger voltage in the first sampling signal and the second sampling signal and the inductor current, and the voltage at the first sampling point can be used as a current detection signal to indicate the magnitude of the inductor current.
  • the combining circuit may further include a third operational amplifier circuit and a fourth operational amplifier circuit.
  • One input terminal of the fourth operational amplifier circuit is connected to the second sampling circuit for receiving the second sampling signal
  • the other input terminal of the fourth operational amplifier circuit is connected to the cathode of the second diode
  • the fourth operational amplifier circuit is connected to the cathode of the second diode.
  • the output end of the circuit is connected to the anode of the second diode
  • one input end of the third operational amplifier circuit is connected to the first sampling circuit for receiving the first sampled signal
  • the other input end of the third operational amplifier circuit is connected to the first sampling circuit.
  • the cathode of the first diode is connected
  • the output end of the third operational amplifier circuit is connected with the anode of the first diode.
  • the voltages of the two input terminals of the third operational amplifier circuit are the voltage of the first sampling signal and the cathode voltage of the first diode, respectively.
  • the voltages of the two input terminals of the third operational amplifier circuit are equal, so the voltage of the first sampled signal and the cathode voltage of the first diode can be kept equal, thus achieving voltage follow-up. Effect.
  • the fourth operational amplifier circuit can keep the voltage of the second sampling signal equal to the cathode voltage of the second diode. Therefore, the voltage of the first connection point can be kept equal to the voltage of the first sampling signal or the second sampling signal, which further improves the current detection accuracy.
  • the combining circuit may further include a grounding resistor, one end of the grounding resistor is connected to the first connection point, and the other end of the grounding resistor is grounded.
  • a grounding resistor By setting the grounding resistance, the voltage of the first connection point can be prevented from being locked at 0V.
  • the Buck-Boost circuit may include a plurality of first bridge arms, a plurality of second bridge arms and a plurality of inductances, the plurality of first bridge arms are connected in parallel, the plurality of second bridge arms are connected in parallel, and the plurality of inductances are respectively connected with the plurality of first bridge arms
  • a bridge arm and a plurality of second bridge arms are connected in a one-to-one correspondence, wherein one end of each inductor is connected to the first bridge arm corresponding to each inductor, and the other end of each inductor is connected to the second bridge arm corresponding to each inductor connect.
  • the detection circuit may detect the sum of the inductor currents of the multiple inductors through the first detection resistor and the second detection resistor.
  • an embodiment of the present application provides a voltage converter, which mainly includes a controller and the voltage conversion circuit provided in any one of the first aspects.
  • the controller can control the voltage conversion circuit to perform voltage conversion.
  • an embodiment of the present application provides an electronic device, which mainly includes the voltage converter provided in the second aspect.
  • 1 is a schematic structural diagram of a voltage converter
  • Figure 2a is a schematic structural diagram of a Buck-Boost circuit
  • 2b to 2e are schematic diagrams of switching states of a Buck-Boost circuit
  • FIG. 3 is a schematic structural diagram of a voltage converter according to an embodiment of the present application.
  • FIG. 4 is a schematic structural diagram of a Buck-Boost circuit provided by an embodiment of the present application.
  • 5a is a schematic diagram of a current change in a detection resistor provided by an embodiment of the present application.
  • FIG. 5b is a schematic diagram of a switch state of a Buck-Boost circuit provided by an embodiment of the present application.
  • FIG. 5c is a schematic diagram of a switch state of a Buck-Boost circuit provided by an embodiment of the present application.
  • 6a is a schematic diagram of a current change in a detection resistor provided by an embodiment of the present application.
  • FIG. 6b is a schematic diagram of a switch state of a Buck-Boost circuit provided by an embodiment of the present application.
  • FIG. 6c is a schematic diagram of a switch state of a Buck-Boost circuit provided by an embodiment of the present application.
  • FIG. 7 is a schematic structural diagram of a detection circuit provided by an embodiment of the present application.
  • FIG. 8 is a schematic structural diagram of a combining circuit according to an embodiment of the present application.
  • connection can be understood as an electrical connection, and the connection of two electrical elements can be a direct or indirect connection between two electrical elements.
  • the connection between A and B can be either a direct connection between A and B, or an indirect connection between A and B through one or more other electrical components, such as the connection between A and B, or the direct connection between A and C, C and B are directly connected, and A and B are connected through C.
  • connection can also be understood as coupling, such as electromagnetic coupling between two inductors. In short, the connection between A and B enables the transmission of electrical energy between A and B.
  • FIG. 1 exemplarily shows a voltage converter.
  • the voltage converter 10 mainly includes a Buck-Boost circuit 11 , a controller 12 and a detection circuit 13 .
  • the Buck-Boost circuit 11 is respectively connected to the controller 12 and the detection circuit 13 , and the controller 12 is connected to the detection circuit 13 .
  • the controller 12 is connected to the detection circuit 13 .
  • the Buck-Boost circuit 11 is also often referred to as a buck-boost conversion circuit. Specifically, when the Buck-Boost circuit 11 performs step-down conversion, the input voltage Vi of the Buck-Boost circuit 11 is greater than the output voltage Vo. When the Buck-Boost circuit 11 performs boost conversion, the input voltage Vi of the Buck-Boost circuit is smaller than the output voltage Vo.
  • the voltage converter 10 having the Buck-Boost circuit 11 is widely used in many power systems.
  • the voltage converter 10 may be a power electronic converter in a power management system of an electric/hybrid vehicle, a battery management system (BMS) in a photovoltaic power generation system, or a communication power supply
  • BMS battery management system
  • the DC power distribution units in the system, etc., are not listed one by one in this application.
  • FIG. 2a is a schematic structural diagram of a Buck-Boost circuit.
  • the Buck-Boost circuit 11 has an H-bridge structure.
  • the Buck-Boost circuit 11 mainly includes a bridge arm 111 , a bridge arm 112 and an inductor 113 , and the inductor 13 is located between the bridge arm 111 and the bridge arm 112 .
  • the bridge arm 111 and the bridge arm 112 are mainly composed of a plurality of switch tubes, and the charging or discharging of the inductor 113 can be adjusted by changing the on or off of each switch tube.
  • the bridge arm 111 includes a switch tube S1 and a switch tube S2, the second electrode of the switch tube S1 is connected to the first electrode of the switch tube S2, and the first electrode of the switch tube S1 and the switch tube S2 are connected.
  • the second electrode of can receive the input voltage V i .
  • the bridge arm 112 includes a switch S3 and a switch S4, the second electrode of the switch S3 is connected to the first electrode of the switch S4, and the first electrode of the switch S3 and the second electrode of the switch S4 can output the output voltage V o .
  • One end of the inductor 113 is connected to the second electrode of the switch S1, and the other end of the inductor 13 is connected to the second electrode of the switch S4.
  • the Buck-Boost circuit 11 may also include an input capacitor C i .
  • One end of the input capacitor C i is connected to the high potential input end of the Buck-Boost circuit 11 , and the other end of the input capacitor C i is connected to the low potential input end of the Buck-Boost circuit 11 .
  • the input capacitor C i can filter the input voltage V i to reduce the ripple of the input voltage V i .
  • the Buck-Boost circuit 11 may further include an output capacitor C o .
  • One end of the input capacitor C o is connected to the high-potential output end of the Buck-Boost circuit 11 , and the other end of the input capacitor C o is connected to the low-potential output end of the Buck-Boost circuit 11 .
  • the output capacitor C o can filter the output voltage V o , so that the Buck-Boost circuit 11 can also continuously output a stable output voltage V o .
  • the Buck-Boost circuit 11 can realize voltage conversion by controlling the switching transistors S1 to S4 to be periodically turned on and off.
  • each cycle mainly consists of the following phases:
  • the state of each switch in the Buck-Boost circuit 11 can be as shown in Figure 2b, wherein the switch S1 and the switch S3 are turned on, and the switch S2 and the switch S4 are turned off.
  • Fig. 2b show the direction of current transmission.
  • the current is input from the high-potential input terminal of the Buck-Boost circuit 11, flows through the switch S1, the inductor 113 and the switch S3 in sequence, and passes through the switch
  • the first electrode of the tube S3 is output from the high potential output terminal of the Buck-Boost circuit 11
  • the return current is input from the low potential output terminal of the Buck-Boost circuit 11 and output from the low potential input terminal of the Buck-Boost circuit 11 .
  • one end of the inductor 113 close to the switch tube S1 has a high potential, and its potential is equal to the potential of the high potential input terminal of the Buck-Boot circuit 11 .
  • the other end of the inductor 113 close to the switch tube S3 has a low potential, and its potential is equal to the potential of the high potential output terminal of the Buck-Boot circuit 11 . Since the low-potential input terminal and the low-potential output terminal of the Buck-Boot circuit 11 are equipotentially connected, the voltage of the inductor 113 is V i -V o .
  • the voltage of the inductor 113 can be understood as the potential difference obtained by subtracting the potential of the inductor 113 close to the other end of the switch S1 and the potential of the inductor 113 close to the other end of the switch S3.
  • the voltage of the inductor 113 in the subsequent embodiments is the same, and details are not repeated here.
  • the current flowing through the inductor 113 may also be referred to as the inductor current i L . Since the inductor current i L cannot increase instantaneously, the inductor current i L gradually increases after the switch S1 and the switch S3 are turned on, and since the input voltage V i is greater than the output voltage V o during the step-down conversion, so this process When the voltage V i -V o of the inductor 113 is greater than 0, the inductor 113 is charged.
  • Fig. 2c shows the direction of current transmission.
  • the current is output from the other end of the inductor 113 close to the switch S3, and passes through the first electrode of the switch S3 from the high potential of the Buck-Boost circuit 11. output terminal output.
  • the returned current is input from the low-potential output terminal of the Buck-Boost circuit 11, and returns to the end of the inductor 113 close to the switch S1 through the switch S2.
  • one end of the inductor 113 close to the switch tube S1 has a low potential, and its low potential is equal to the potential of the low-potential output terminal of the Buck-Boot circuit 11 .
  • the other end of the inductor 113 close to the switch tube S3 has a high potential, and its potential is equal to the potential of the high potential output terminal of the Buck-Boot circuit 11 . Further, it can be obtained that the voltage of the inductor 113 is -V o .
  • the inductor current i L cannot be reset to zero instantaneously, the inductor current i L gradually decreases after the switch S1 is turned off.
  • the inductor 113 will begin to discharge, and this process can also be referred to as the inductor 113 freewheeling.
  • the inductor current i L output by the inductor 113 is output through the switch S3.
  • the Buck-Boost circuit 11 can realize step-down conversion after the above-mentioned inductor charging stage and inductor discharging stage.
  • each cycle mainly consists of the following phases:
  • the arrow in Figure 2d shows the direction of current transmission.
  • the current is input from the first electrode of the switch S1, flows through the switch S1, the inductor 113 and the switch S4 in sequence, and flows from the Buck-Boost circuit. 11's low-potential input terminal output.
  • one end of the inductor 113 close to the switch tube S1 has a high potential, and its potential is equal to the potential of the high potential input terminal of the Buck-Boot circuit 11 .
  • the other end of the inductor 113 close to the switch tube S3 has a low potential, and its potential is equal to the potential of the low potential input terminal of the Buck-Boot circuit 11 . Therefore, the voltage of the inductor 113 is V i .
  • the inductor 113 is charged, the output capacitor C o is discharged, and the output voltage V o is equal to the voltage of the output capacitor C o .
  • Fig. 2e shows the direction of current transmission.
  • the current is input from the high potential input terminal of the Buck-Boot circuit 11. High potential output terminal output.
  • the returned current is input from the low-potential output terminal of the Buck-Boost circuit 11 and output from the low-potential input terminal of the Buck-Boost circuit 11 .
  • one end of the inductor 113 close to the switch tube S1 has a low potential, and the potential is equal to the potential of the high potential output terminal of the Buck-Boot circuit 11 .
  • One end of the inductor 113 close to the switch tube S3 has a high potential, and its potential is equal to the potential of the high potential output terminal of the Buck-Boot circuit 11 . Since the low-potential input terminal and the low-potential output terminal of the Buck-Boot circuit 11 are equipotentially connected, the voltage of the inductor 113 is V i -V o .
  • the inductor current i L cannot be reset to zero instantaneously, the inductor current i L gradually decreases after the switch S1 and the switch S3 are turned on, and since the input voltage V i is smaller than the output voltage V o during the boost conversion, so during this process When the voltage V i -V o of the inductor 113 is less than 0, the inductor 113 is discharged.
  • the Buck-Boost circuit 11 can realize boost conversion after the above-mentioned inductor charging stage and inductor discharging stage.
  • the controller 12 can provide the same or different control signals for the switches S1 to S4 respectively, so as to control the on and off of the switches S1 to S4 respectively, so that the Buck-Boost circuit 11 can realize the above voltage conversion.
  • the controller 12 may be a logic circuit capable of generating control signals, for example, the controller 12 may be a general-purpose central processing unit (CPU), a general-purpose processor, a digital signal processing (DSP), Application specific integrated circuits (ASIC), field programmable gate array (FPGA), microcontroller (MCU), or other programmable logic devices, transistor logic devices, hardware components or any combination thereof.
  • the detection circuit 13 can detect the working state of the Buck-Boost circuit 11, and feed back the detected working state information to the controller 12, so that the controller 12 can adjust the information provided to the switch tubes S1 to 12 according to the working state information of the Buck-Boost circuit 11.
  • the control signal of the switch S4 that is to say, the controller 12 can realize the closed-loop control of the Buck-Boost circuit 11 through the detection circuit 13 .
  • the detection circuit 13 is often required to detect the inductor current i L in the Buck-Boost circuit 11 .
  • the inductor current i L detected by the detection circuit 13 can be used for closed-loop control.
  • the controller 12 can adjust the control signals provided to the switches S1 to S4 according to the inductor current i L detected by the detection circuit 13 , thereby realizing closed-loop control.
  • the inductor current detected by the detection circuit 13 can also be used for over current protection (OCP).
  • OCP over current protection
  • the controller 12 may control the Buck-Boost circuit 11 to stop the voltage conversion of the input voltage V i when the inductor current i L detected by the detection circuit 13 exceeds the current threshold.
  • the detection circuit 13 mainly includes a current sensor, and the current sensor is a Hall element connected in series with the inductor 113 .
  • the current sensor is a Hall element connected in series with the inductor 113 .
  • the controller 12 can then determine the magnitude of the current inductor current i L according to the output signal of the current sensor.
  • the current cost of most current sensors is relatively high, which is not conducive to saving the cost of the voltage converter 10 .
  • the current sensor detects the inductor current i L based on the Hall effect, the detection delay of the current sensor is relatively large, which limits the application of the inductor current i L in some scenarios.
  • the controller 12 may not be able to immediately control the Buck-Boost circuit 11 to stop working when the inductor current i L is too large, and the Buck-Boost circuit 11 is increased. risk of damage.
  • an embodiment of the present application provides a detection circuit, which includes a first detection resistor and a second detection resistor.
  • the first detection resistor and the second detection resistor can be connected to the Buck-Boost circuit.
  • the inductor current i L can flow through the first detection resistor and the second detection resistor. at least one of the sense resistors. Therefore, the detection circuit can detect the inductor current i L on the basis of the first detection resistor and the second detection resistor.
  • FIG. 3 exemplarily shows a schematic structural diagram of a voltage converter provided by an embodiment of the present application.
  • the voltage converter 30 mainly includes a Buck-Boost circuit 31 and a detection circuit 33 .
  • the voltage converter 30 may further include a controller 32, and the controller 32 may control the Buck-Boost circuit 31 to perform voltage conversion.
  • the controller 32 can also receive the current detection signal provided by the detection circuit 33 , and the specific implementation of the controller 32 is similar to that of the aforementioned controller 12 , which is not repeated here.
  • the Buck-Boost circuit 31 has an H-bridge structure, including a bridge arm 311 , a bridge arm 312 , and an inductor 313 , and the inductor 313 is located between the bridge arm 311 and the bridge arm 312 .
  • the H-bridge structure in the Buck-Boost circuit 31 is mainly composed of the inductor 313, the bridge arm 311 and the bridge arm 312, and the H-bridge structure is the same as the H-bridge structure in the Buck-Boost circuit 11 (mainly composed of the inductor 113).
  • the bridge arm 111 and the bridge arm 112 are similar, and the repeated places will not be repeated.
  • the switching transistors S1 to S4 may be relays, metal oxide semiconductor field effect transistors (metal oxide semiconductor field effect transistors, MOSFETs), bipolar junction transistors (bipolar junction transistors, BJT), insulating One or more of various types of switching transistors such as a gate bipolar transistor (insulated gate bipolar transistor, IGBT), which are not listed one by one in this embodiment of the present application.
  • metal oxide semiconductor field effect transistors metal oxide semiconductor field effect transistors, MOSFETs
  • bipolar junction transistors bipolar junction transistors
  • IGBT insulated gate bipolar transistor
  • the H-bridge structure in the Buck-Boost circuit 31 in FIG. 3 is only an example, and in a specific implementation structure, the Buck-Boost circuit 31 may also have other types of implementations.
  • the bridge arm 311 may include N first bridge arms 311 and N second bridge arms 312, and N inductors 113 (inductor 113-1 to inductor 113-N), where N is greater than or equal to An integer of 1.
  • the switch tube S11 and the switch tube S12 belong to the same first bridge arm
  • the switch tube S21 and the switch tube S22 belong to the same first bridge arm
  • the switch tube SN1 and the switch tube SN2 belong to the same first bridge arm arm
  • the switch tube S13 and the switch tube S14 belong to the same second bridge arm
  • the switch tube S23 and the switch tube S24 belong to the same second bridge arm
  • the switch tube SN3 and the switch tube SN4 belong to the same second bridge arm.
  • N first bridge arms are connected in parallel, and N second bridge arms are connected in parallel.
  • the first electrode of the switch S11 to the first electrode of the switch SN1 are all connected to the high potential input terminal of the Buck-Boost circuit 31
  • the first electrode of the switch S12 to the second electrode of the switch SN2 are all connected to The low-potential input end of the Buck-Boost circuit 31
  • the first electrode of the switch S13 to the first electrode of the switch SN3 are all connected to the high-potential output end of the Buck-Boost circuit 31
  • the first electrode of the switch S14 is connected to the switch
  • the second electrodes of the tube SN4 are all connected to the low-potential output terminals of the Buck-Boost circuit 31 .
  • the N inductors in the Buck-Boost circuit 31 are respectively connected to the N first bridge arms and the N second bridge arms in a one-to-one correspondence.
  • One end of each inductor is connected to the corresponding first bridge arm, and the other end of each inductor is connected to the corresponding first bridge arm. connected with the corresponding second bridge arm.
  • one end of the inductor 313-1 is connected to the first bridge arm where the switch S11 and the switch S12 are located, and the other end of the inductor 313-1 is connected to the second bridge arm where the switch S13 and the switch S14 are located.
  • One end of the inductor 313-2 is connected to the first bridge arm where the switch S21 and the switch S22 are located, and the other end of the inductor 313-2 is connected to the second bridge arm where the switch S23 and the switch S24 are located.
  • One end of the inductor 313-N is connected to the first bridge arm where the switch transistors SN1 and SN2 are located, and the other end of the inductor 313-N is connected to the second bridge arm where the switch transistors SN3 and SN4 are located.
  • the following embodiments of the present application take the Buck-Boost circuit 31 shown in FIG. 3 as an example for description. It should be pointed out that the embodiments of the present application are also applicable to a scenario in which the Buck-Boost circuit 31 includes two or more inductors 313 .
  • the detection circuit 33 includes a detection resistor R1 and a detection resistor R2.
  • One end of the detection resistor R1 is connected to one input end of the Buck-Boost circuit 31
  • the other end of the detection resistor R1 is connected to one end of the bridge arm 311
  • the other end of the bridge arm 311 is connected to the other input end of the Buck-Boost circuit 31 connect.
  • One end of the detection resistor R2 is connected to one output end of the Buck-Boost circuit 31
  • the other end of the detection resistor R2 is connected to one end of the bridge arm 312
  • the other end of the bridge arm 312 is connected to the other output end of the Buck-Boost circuit 31 .
  • one is a high-potential input terminal and the other is a low-potential input terminal, and the potential difference after subtracting the low-potential input terminal from the high-potential input terminal is the input voltage V i .
  • the two output terminals of the Buck-Boost circuit 31 one is a high potential output terminal and the other is a low potential output terminal. The potential difference after subtracting the low potential output terminal from the high potential output terminal is the output voltage V o .
  • one end of the detection resistor R1 is connected to one input end of the Buck-Boost circuit 31, and the other end of the detection resistor R1 is connected to one end of the bridge arm 311", which can be understood as the switch tube S1 in the bridge arm 311
  • the first electrode of is connected to the high potential input terminal of the Buck-Boost circuit 31 through the detection resistor R1.
  • the second electrode of the switch S2 is connected to the low-potential input terminal of the Buck-Boost circuit 31 .
  • One end of the detection resistor R1 is connected to one input end of the Buck-Boost circuit 31, and the other end of the detection resistor R1 is connected to one end of the bridge arm 311", which can also be understood as the second electrode of the switch tube S2 in the bridge arm 311 passing the detection
  • the resistor R1 is connected to the low potential input terminal of the Buck-Boost circuit 31 .
  • the first electrode of the switch S1 in the bridge arm 311 is connected to the high-potential input terminal of the Buck-Boost circuit 31 .
  • connection relationship between the detection resistor R2 and one output end of the Buck-Boost circuit 31 and one end of the bridge arm 312 is the same, and will not be repeated here.
  • the detection resistor R1 when one end of the detection resistor R1 is connected to the low-potential input end of the Buck-Boost circuit 31, and one end of the detection resistor R2 is connected to the low-potential output end of the Buck-Boost circuit 31, the potential at both ends of the detection resistor R1 and the detection The potentials at both ends of the resistor R2 are relatively low, and the common-mode voltage (voltage to ground) at both ends of the two detection resistors is relatively low, which is beneficial to improve the sampling accuracy of the resistance voltage by the detection circuit 33 .
  • the Buck-Boost circuit 31 may further include an input capacitor C i , one end of the input capacitor C i is connected to the high-potential input end of the Buck-Boost circuit 31 , and the input capacitor C i The other end is connected to the low potential input end of the Buck-Boost circuit 31 .
  • the detection resistor R1 may be located between the input capacitor Ci and the bridge arm 311 .
  • one end of the detection resistor R1 is also connected to the other end of the input capacitor Ci, and the other end of the detection resistor R1 is connected to the second electrode of the switch tube S2 in the bridge arm 311.
  • the input capacitor C i has the function of filtering, if the detection resistor R1 is located between the low-potential input terminal of the Buck-Boost circuit 31 and the input capacitor C i , that is, the input capacitor C i passes through the detection resistor R1 and the Buck- If the low-potential input terminal of the boost circuit 31 is connected, the current passing through the detection resistor R1 will be the average current of the inductor current i L. Although the average current of the inductor current i L can be detected by detecting the resistance voltage of the resistor R1 in this case, this implementation is not conducive to detecting the real-time inductor current i L .
  • the filtering effect of the input capacitor C i does not affect the current through the detection resistor R1, that is, the current through the detection resistor R1 can be real-time
  • the inductor current i L is therefore beneficial to detect the real-time inductor current i L by detecting the resistance voltage of the resistor R1 .
  • the Buck-Boost circuit 31 may further include an output capacitor C o , one end of the output capacitor C o is connected to the high-potential output end of the Buck-Boost circuit 31 , and the other end of the output capacitor C o is connected to the low-potential output end of the Buck-Boost circuit 31 .
  • Potential output connection one end of the output capacitor C o is connected to the high-potential output end of the Buck-Boost circuit 31 , and the other end of the output capacitor C o is connected to the low-potential output end of the Buck-Boost circuit 31 .
  • the detection resistor R2 may be located between the bridge arm 312 and the output capacitor C o .
  • one end of the detection resistor R2 is also connected to the other end of the output capacitor C o
  • the other end of the detection resistor R1 is connected to the second electrode of the switch S4 in the bridge arm 312 .
  • This implementation is beneficial to detect the real-time inductor current i L by detecting the resistance voltage of the resistor R2 , and details are not repeated here.
  • the inductor current i L can pass through at least one of the detection resistor R1 and the detection resistor R2, so that the detection circuit 33 can pass through at least one of the detection resistor R1 and the detection resistor R2.
  • the resistance voltages of the detection resistor R1 and the detection resistor R2 detect the magnitude of the inductor current i L.
  • the detection circuit 33 is connected to the detection resistor R1 and the detection resistor R2, respectively. Specifically, the detection circuit 33 is connected to both ends of the detection resistor R1 and both ends of the detection resistor R2, respectively. The detection circuit 33 can detect the resistance voltage VR1 of the detection resistor R1 and the resistance voltage VR2 of the detection resistor R2 , respectively.
  • the detection circuit 33 can further output the current detection signal Va according to the maximum voltage among the resistance voltage VR1 and the resistance voltage VR2 .
  • the maximum voltage among the resistance voltage VR1 and the resistance voltage VR2 may be the voltage of the detection resistance through which the inductor current i L passes in the detection resistance R1 and the detection resistance R2. Therefore, the current detection signal Va outputted according to the maximum voltage of the resistance voltage VR1 and the resistance voltage VR2 can indicate the magnitude of the inductor current i L passing through the detection resistance R1 and/or the detection resistance R2.
  • the resistance values of the detection resistor R1 and the detection resistor R2 are equal. Based on the positions of the detection resistor R1 and the detection resistor R2 in the Buck-Boost circuit 31, the maximum voltage in the resistor voltage V R1 and the resistor voltage V R2 is related to the inductance. The current i L always maintains a proportional relationship, and the ratio is the resistance value of the detection resistor R1 and the detection resistor R2.
  • FIG. 5a it is a schematic diagram of current changes of the detection resistor R1 and the detection resistor R2 during the step-down conversion process.
  • the period of the step-down conversion is T1, that is, the Buck-Boost circuit 31 can complete one step-down conversion every time T1.
  • each T1 includes two time periods t1 and t2, where t1 represents the inductor charging phase in the buck conversion, and t2 represents the inductor freewheeling phase in the buck conversion.
  • i R2 represents the current flowing through the detection resistor R2, and i R1 represents the current flowing through the detection resistor R1.
  • Inductor charging stage in the inductive charging stage of the step-down conversion, the switch S1 and the switch S3 are turned on, the switch S2 and the switch S4 are turned off, and the current flows from the Buck-Boost circuit 31
  • the high-potential input end of flows through the switch S1 , the inductor 113 and the switch S3 in sequence, and is output from the high-potential end of the Buck-Boost circuit 31 through the first electrode of the switch S3 .
  • the returning current is input from the low-potential output terminal of the Buck-Boost circuit 31 , flows through the detection resistor R2 and the detection resistor R1 in sequence, and is output from the low-potential input terminal of the Buck-Boost circuit 31 .
  • the inductor 313, the detection resistor R2 and the detection resistor R1 are connected in series in sequence, so the current i R1 flowing through the detection resistor R1 and the current i R2 flowing through the detection resistor R2 are equal to the inductor current i L .
  • the inductor current i L increases gradually, so as shown in Figure 5a, in the time period t1, the current i R1 flowing through the detection resistor R1 and the current i R2 flowing through the detection resistor R2 are also gradually increase.
  • the resistance values of the detection resistor R1 and the detection resistor R2 are equal, so in the inductor charging stage of the step-down conversion, the resistance The voltage VR1 and the resistance voltage VR2 are equal, the maximum voltage among the resistance voltage VR1 and the resistance voltage VR2 is the resistance voltage VR1 and the resistance voltage VR2 , and the resistance voltage VR1 and the resistance voltage VR2 and the inductor current iL The ratio between them is the resistance value of the detection resistor R1 and the detection resistor R2.
  • Inductance freewheeling stage As mentioned above, please refer to Figure 5c, in the inductance freewheeling stage of step-down conversion, switch S1 is turned off, switch S2 is turned on, switch S3 is kept on, and switch S4 is kept off .
  • the current is output from one end of the inductor 313 close to the switch S3, and is output through the high-potential output end of the Buck-Boost circuit 31 after being transmitted through the switch S3.
  • the returning current is input from the low-potential output terminal of the Buck-Boost circuit 31 , and the current flows through the detection resistor R2 and the switch S2 in sequence, so as to return to the end of the inductor 313 close to the switch S1 .
  • the inductor 313 is connected in series with the sense resistor R2, so the current i R2 flowing through the sense resistor R2 is equal to the inductor current i L .
  • the inductor current i L decreases gradually, so as shown in FIG. 5a, in the time period t2, the current i R2 flowing through the detection resistor R2 also decreases gradually. Since no current flows through the detection resistor R1 during the inductance freewheeling phase of the step-down conversion, as shown in FIG. 5a, the current i R1 of the detection resistor R1 is zero in the time period t2.
  • the resistor voltage VR 2 is greater than the resistor voltage VR 1 , that is, the maximum value of the resistor voltage VR 1 and the resistor voltage VR 2
  • the voltage is the resistor voltage VR2
  • the ratio between the resistor voltage VR2 and the inductor current i L is the resistance value of the detection resistor R2 .
  • FIG. 6a it is a schematic diagram of current changes of the detection resistor R1 and the detection resistor R2 during the boost conversion process.
  • the period of the boost conversion is T2, that is, every time T2, the Buck-Boost circuit 31 can complete a boost conversion.
  • each T2 includes two time periods t3 and t4, wherein t3 represents the inductor charging phase in the boost conversion, and t4 represents the inductor freewheeling phase in the boost conversion.
  • i R2 represents the current flowing through the detection resistor R2
  • i R1 represents the current flowing through the detection resistor R1.
  • Inductor charging stage As mentioned above, please refer to Figure 6b, in the inductive charging stage of boost conversion, switch S1 and switch S4 are turned on, switch S2 and switch S3 are disconnected, and the current flows from Buck-Boost circuit 31
  • the high-potential input terminal of 113 flows through the switch S1, the inductor 113, the switch S4 and the detection resistor R1 in sequence, and then outputs from the low-potential input terminal of the Buck-Boost circuit 11.
  • the inductor 313 is connected in series with the sense resistor R1, so the current i R1 flowing through the sense resistor R1 is equal to the inductor current i L .
  • the inductor current i L increases gradually, so as shown in FIG. 6a, in the time period t3, the current i R1 flowing through the detection resistor R1 also increases gradually. Since no current flows through the detection resistor R2 during the inductor charging phase of the boost conversion, as shown in FIG. 6a, the current i R2 of the detection resistor R2 is zero in the time period t3.
  • the resistor voltage VR 1 is greater than the resistor voltage VR 2
  • the maximum voltage among the resistor voltage VR 1 and the resistor voltage VR 2 is the resistor voltage VR1
  • the ratio between the resistor voltage VR1 and the inductor current i L is the resistance value of the detection resistor R1 .
  • Inductance freewheeling stage As mentioned above, please refer to Figure 6c, in the inductance freewheeling stage of boost conversion, the switch S3 is turned on, the switch S4 is turned off, the switch S1 is kept on, and the switch S2 is kept off .
  • the current is input from the high-potential input terminal of the Buck-Boost circuit 31 , flows through the switch S1 , the inductor 313 and the switch S3 in sequence, and the switch S3 is output from the high-potential output terminal of the Buck-Boost circuit 31 .
  • the returning current is input from the low-potential output terminal of the Buck-Boost circuit 31 , flows through the detection resistor R2 and the detection resistor R1 in sequence, and is output through the low-potential input terminal of the Buck-Boost circuit 31 .
  • the inductor 313, the detection resistor R2 and the detection resistor R1 are connected in series in sequence, so the current i R1 flowing through the detection resistor R1 and the current i R2 flowing through the detection resistor R2 are equal to the inductor current i L .
  • the inductor current i L decreases gradually, so as shown in Figure 6a, in the time period t4, the current i R1 flowing through the detection resistor R1 and the current i R2 flowing through the detection resistor R2 are also Gradually decreases.
  • the resistance values of the detection resistor R1 and the detection resistor R2 are equal, so in the inductor charging stage of the step-down conversion, the resistance The voltage VR1 and the resistance voltage VR2 are equal, the maximum voltage among the resistance voltage VR1 and the resistance voltage VR2 is the resistance voltage VR1 and the resistance voltage VR2 , and the resistance voltage VR1 and the resistance voltage VR2 and the inductor current iL The ratio between them is the resistance value of the detection resistor R1 and the detection resistor R2.
  • the maximum voltage in the resistor voltage V R1 and the resistor voltage V R2 always maintains an equal proportional relationship with the inductor current i L , and the correlation
  • the coefficient is the resistance value of the detection resistor R1 and the detection resistor R2.
  • the detection circuit 33 can further output the current detection signal Va according to the maximum voltage among the resistance voltage VR1 and the resistance voltage VR2 , so that the current detection signal Va can indicate the inductor current i passing through the detection resistance R1 and/or the detection resistance R2 L.
  • the detection delay of the detection circuit 33 is short.
  • the cost of the detection resistor R1 and the detection resistor R2 is lower, so the embodiment of the present application is also beneficial to reduce the cost of the voltage converter 30 .
  • the detection circuit 33 can output the current detection signal Va according to the maximum voltage of the resistance voltage VR1 and the resistance voltage VR2 .
  • the current detection signal Va may be a voltage signal, and there is a one-to-one correspondence between the voltage of the current detection signal Va and the maximum voltage of the resistor voltage VR1 and the resistor voltage VR2 .
  • the magnitude of the voltage of the current detection signal Va can indicate the magnitude of the inductor current i L.
  • the one-to-one correspondence between the voltage of the current detection signal Va and the inductor current i L may be known or known, so that the current detection
  • the receiving end of the signal Va can determine the magnitude of the inductor current i L according to the magnitude of the voltage of the received voltage detection signal Va and the correlation between the magnitude of the voltage of the current detection signal Va and the inductor current i L.
  • V max i L *R (Formula 1)
  • R represents the resistance value of the detection resistor R1 and the detection resistor R2.
  • V a a i L *R+b (Formula 3)
  • the one-to-one correspondence shown in Formula 3 may be known, and the values of a, R, and b may also be known.
  • the receiving end can obtain the magnitude of the inductor current i L according to the voltage of the current detection signal Va and the one-to-one correspondence shown in Formula 3.
  • the following embodiments of the present application take the one-to-one correspondence between the voltage of the current detection signal Va and the maximum voltage in the resistance voltage VR1 and the resistance voltage VR2 as the positive correlation shown in formula 3 as Example to illustrate, where a is greater than 0.
  • Application scenarios under other relevant relationships can be obtained after adaptive adjustment on the basis of the subsequent description of the embodiments of the present application, and should also be included in the embodiments of the present application.
  • the above examples are all described by taking a scenario where there is only one inductor 313 in the Buck-Boost31 circuit as an example.
  • the magnitude of the inductor current i L indicated by the current detection signal Va should be one of the charging and discharging processes in the Buck-Boost circuit 31 . or the sum of the inductor currents of multiple inductors 313 .
  • FIG. 3 exemplarily shows a schematic structural diagram of a detection circuit provided by an embodiment of the present application.
  • the detection circuit 33 further includes a sampling circuit 331 , a sampling circuit 332 and a combining circuit 333 .
  • the sampling circuit 331 is respectively connected to both ends of the detection resistor R1 and the combining circuit 333
  • the sampling circuit 332 is respectively connected to both ends of the detection resistor R2 and the combining circuit 333 .
  • the sampling circuit 331 can sample the resistance voltage VR1 of the detection resistance R1 . Specifically, the sampling circuit 331 can output the sampling signal V b1 to the combining circuit 333 according to the resistance voltage V R1 of the detection resistor R1 .
  • the sampling signal V b1 may be a voltage signal, and the magnitude of the voltage of the sampling signal V b1 may have a positive correlation with the magnitude of the resistor voltage V R1 , that is, the voltage of the sampling signal V b1 may vary with the resistor voltage V R1 . increases with the increase of , and decreases with the decrease of the resistor voltage V R1 .
  • the sampling circuit 331 may include an operational amplifier circuit U1, one input terminal of the operational amplifier circuit U1 is connected to one end of the detection resistor R1, and the other input terminal of the operational amplifier circuit U1 is connected to the detection resistor R1. The other end is connected, and the output end of the operational amplifier circuit U1 is connected to the combining circuit 333 .
  • the operational amplifier circuit U1 can differentially sample and amplify the resistance voltage VR1 of the detection resistor R1 , so that the above-mentioned sampling signal V b1 can be output from the output end of the operational amplifier circuit U1 .
  • the sampling circuit 332 can sample the resistance voltage VR2 of the detection resistance R2 . Specifically, the sampling circuit 332 can output the sampling signal V b2 to the combining circuit 333 according to the resistance voltage V R2 of the detection resistor R2 .
  • the sampling signal V b2 may be a voltage signal
  • the magnitude of the voltage of the sampling signal V b2 and the magnitude of the resistor voltage V R2 may have a positive correlation
  • the voltage of the sampling signal V b2 may increase as the resistor voltage V R2 increases. increases and decreases as the resistor voltage VR2 decreases.
  • the sampling circuit 332 may include an operational amplifier circuit U2, one input end of the operational amplifier circuit U2 is connected to the other end of the detection resistor R2, and the other input end of the operational amplifier circuit U2 is connected to the detection resistor R2. One end of the operational amplifier circuit U2 is connected to the output end of the operational amplifier circuit U2 and the combining circuit 333 is connected.
  • the operational amplifier circuit U2 can differentially sample and amplify the resistance voltage VR2 of the detection resistor R2 , so that the above sampling signal V b2 can be output from the output end of the operational amplifier circuit U2.
  • the positive correlation between the sampling signal V b1 and the resistance voltage VR1 and the correlation between the sampling signal V b2 and the resistance voltage VR2 can be the same positive correlation, so as to ensure that the sampling circuit 331 and the sampling The sampling result of the circuit 332 does not change the relative magnitude relationship between the resistor voltage VR1 and the resistor voltage VR2 . That is to say, the above-mentioned operational amplifier circuit U1 and operational amplifier circuit U2 may have the same circuit structure.
  • the voltage of the sampling signal V b1 is equal to the resistance voltage VR1
  • the voltage of the sampling signal V b2 is equal to the resistance voltage VR2
  • the voltage of the sampling signal V b1 is equal to c V R1 +d
  • the voltage of the sampling signal V b2 is equal to c V R2 +d, where c is a constant greater than 0, and d is an arbitrary constant.
  • the non-inverting input terminal (+) of the operational amplifier circuit U1 can be connected to the high potential terminal of the detection resistor R1, and the inverting input terminal (-) of the operational amplifier circuit U1 can be connected to the low potential terminal of the detection resistor R1.
  • the non-inverting input terminal (+) of the operational amplifier circuit U2 can be connected to the high potential terminal of the detection resistor R2, and the reverse input terminal (-) of the operational amplifier circuit U1 can be connected to the low potential terminal of the detection resistor R2.
  • one end of the detection resistor R1 connected to the low potential input end of the Buck-Boost circuit 11 is a low potential end, and the other end connected to the detection resistor R1 and the detection resistor R2 is a high potential end.
  • One end of the detection resistor R2 connected to the low-potential output end of the Buck-Boost circuit 11 is a high-potential end, and the other end of the detection resistor R2 connected to the detection resistor R1 is a low-potential end.
  • the inverting input terminal of the operational amplifier circuit U1 can be connected to the end of the detection resistor R1 close to the low potential input terminal of the Buck-Boost circuit 11, and the non-inverting input terminal of the operational amplifier circuit U1 can be connected to the detection resistor R1.
  • Resistor R1 is connected close to one end of sense resistor R2.
  • the inverting input end of the operational amplifier circuit U2 can be connected to the end of the detection resistor R2 close to the detection resistor R1, and the non-inverting input end of the operational amplifier circuit U2 can be connected to the end of the detection resistor R2 close to the low potential output end of the Buck-Boost circuit 11.
  • the combining circuit 333 can receive the sampling signal V b1 and the sampling signal V b2 provided by the detection circuit 331 , and then can output the current detection signal Va according to the maximum voltage of the sampling signal V b1 and the sampling signal V b2 .
  • the positive correlation between the sampling signal V b1 and the resistance voltage VR1 and the correlation between the sampling signal V b2 and the resistance voltage VR2 can be the same positive correlation, so the sampling signal V b1 and the sampling The above positive correlation is also satisfied between the maximum voltage in the signal V b2 and the maximum voltage in the resistance voltage VR1 and the resistance voltage VR2 .
  • the combining circuit 332 can output the current detection signal Va according to the maximum voltage in the sampling signal V b1 and the sampling signal V b2 , so that the current detection signal Va can indicate the inductor current i L passing through the detection resistor R1 and/or the detection resistor R2. size.
  • the combining circuit 333 mainly includes a diode D1 and a diode D2 .
  • the anode of the diode D1 is connected to the sampling circuit 331 and can receive the sampling signal V b1 provided by the sampling circuit 331 .
  • the anode of the diode D2 is connected to the sampling circuit 332 and can receive the sampling signal V b2 provided by the sampling circuit 332 .
  • the cathode of the diode D1 and the cathode of the diode D2 are connected through a connection point P, and the voltage of the connection point P can be used as the current detection signal Va.
  • diode D1 since the cathodes of diodes D1 and D2 are connected, a diode with a larger anode voltage will turn off a diode with a lower anode voltage. For example, if the anode voltage of diode D1 is greater than the anode voltage of diode D2, diode D2 will be turned off. Likewise, if the anode voltage of diode D2 is greater than the anode voltage of diode D1, diode D1 will be turned off.
  • the anode voltage of the diode D1 is the voltage of the sampling signal V b1
  • the anode voltage of the diode D2 is the voltage of the sampling signal V b2 . Therefore, when the voltage of the sampling signal V b1 is greater than the voltage of the sampling signal V b2 , the diode D1 is turned on, and the voltage of the connection point P is the voltage of the sampling signal V b1 .
  • the diode D2 is turned on, and the voltage of the connection point P is the voltage of the sampling signal V b2 .
  • both the diode D1 and the diode D2 can be turned on, and the voltage of the connection point P is the voltage of the sampling signal V b1 and the sampling signal V b2 .
  • the voltage of the connection point P is the maximum voltage between the voltage of the sampling signal V b1 and the voltage of the sampling signal V b2 , so the voltage of the connection point P can be used as the above current Detection signal Va .
  • the combining circuit 333 may further include an operational amplifier circuit U3 and an operational amplifier circuit U4.
  • One input end of the operational amplifier circuit U3 is connected to the sampling circuit 331, and can receive the above-mentioned sampling signal V b1 .
  • the other input terminal of the operational amplifier circuit U3 is connected to the cathode of the diode D1, and the output terminal of the operational amplifier circuit U3 is connected to the anode of the diode D1.
  • One input terminal of the operational amplifier circuit U4 is connected to the sampling circuit 332, and can receive the sampling signal V b2 .
  • the other input terminal of the operational amplifier circuit U4 is connected to the cathode of the diode D2, and the output terminal of the operational amplifier circuit U4 is connected to the anode of the diode D2.
  • the input terminal connected to the operational amplifier circuit U1 in the operational amplifier circuit U3 may be a non-inverting input terminal, and the input terminal connected to the diode D1 may be an inverting input terminal.
  • the input terminal connected to the operational amplifier circuit U2 may be a non-inverting input terminal, and the input terminal connected to the diode D2 may be an inverting input terminal.
  • the voltages of the two input terminals of the operational amplifier circuit U3 are the voltage of the sampling signal V b1 and the cathode voltage of the diode D1 respectively.
  • the voltages of the two input terminals of the operational amplifier circuit U3 are equal, so the voltage of the sampling signal V b1 and the cathode voltage of the diode D1 can be kept equal, thus achieving the effect of voltage following.
  • the operational amplifier circuit U4 which will not be repeated here.
  • the combining circuit 333 may further include a grounding resistor R3.
  • One end of the grounding resistor R3 is connected to the connection point P, and the other end of the grounding resistor R3 is grounded.
  • the detection circuit 33 can generate the current detection signal Va based on the detection resistor R1 and the detection resistor R2, so as to realize the detection of the inductor current i L. Compared with the current detection scheme based on the current sensor, the embodiment of the present application performs sampling through the detection resistor, and the sampling result is more accurate and rapid. It is worth noting that the detection circuit 33 in the embodiment of the present application can automatically adapt to different voltage conversion processes of the Buck-Boost circuit 31, without additional control, and is also beneficial to save control resources.
  • an embodiment of the present application further provides an electronic device, which mainly includes the voltage converter provided by any of the above-mentioned embodiments of the present application.
  • the electronic device may be an electric vehicle, a photovoltaic power station, a communication power supply device, and the like.

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Abstract

一种电压转换电路、电压转换器及电子设备，该电压转换电路主要包括具有第一检测电阻和第二检测电阻的检测电路（33），以及H桥结构的Buck-Boost电路（31）。第一检测电阻连接于Buck-Boost电路（31）的一个输入端和H桥结构的一个桥臂（311）之间，第二检测电阻连接于Buck-Boost电路（31）的一个输出端和H桥结构的另一个桥臂（312）之间，检测电路（33）可以根据第一检测电阻和第二检测电阻的电阻电压输出电流检测信号。不仅实现了对电感（313）电流的检测，还有利于降低电感（313）电流的检测成本，以及缩小电感（313）电流的检测时延。

Description

一种电压转换电路、电压转换器及电子设备 技术领域
本申请涉及电压转换器技术领域，尤其涉及一种电压转换电路、电压转换器及电子设备。
背景技术
降压-升压(Buck-Boost)电路是一种常见的直流-直流电压(电流)转换电路，常被用于多种类型的电力系统内的电压转换器中。例如，电动/混合动力汽车的电源管理系统、光伏发电系统、通信电源供电系统等电力系统内的电压转换器，皆需要使用Buck-Boost电路实现电压转换。
一般来说，Buck-Boost电路中主要包括多个开关管和电感，通过改变各个开关管的导通和断开，可以控制Buck-Boost电路中电感的充放电状态，从而实现电压转换。在Buck-Boost电路的一些应用场景中，往往需要检测Buck-Boost电路中的电感电流。例如，电压转换器可以根据Buck-Boost电路中的电感电流监控Buck-Boost电路的工作状态，再例如，电压转换器还可以根据Buck-Boost电路中的电感电流进行过流保护(over current protection，OCP)，等等。
在目前的一些检测方案中，可以在Buck-Boost电路中增加与电感串联的电流传感器(一种霍尔元件)，电流传感器可以检测流经电感的电感电流并输出电流检测信号，以指示当前电感电流的大小。然而，电流传感器的成本较高，不利于节省成本。而且，电流传感器的检测时延较大，使得检测结果的应用范围存在一定局限。
发明内容
本申请提供一种电压转换电路、电压转换器及电子设备，可以对电压转换电路中的电感电流进行检测的同时，有利于降低电感电流的检测成本，还有利于缩小电感电流的检测时延。
第一方面，本申请实施例提供一种电压转换电路，主要包括具有第一检测电阻和第二检测电阻的检测电路，以及H桥结构的Buck-Boost电路。具体来说，Buck-Boost电路包括第一桥臂、第二桥臂和电感，电感位于第一桥臂和第二桥臂之间，第一桥臂的两端分别和第二桥臂的两端一一对应连接。其中，第一桥臂的一端通过第一检测电阻与Buck-Boost电路的一个输入端连接，第一桥臂的另一端与Buck-Boost电路的另一个输入端连接。第二桥臂的一端通过第二检测电阻与Buck-Boost电路的一个输出端连接，第二桥臂的另一端与Buck-Boost电路的另一个输出端连接。
检测电路可以分别对第一检测电阻的第一电阻电压和第二检测电阻的第二电阻电压进行电压采样，检测电路进而可以根据第一电阻电压和第二电阻电压中的最大电压输出电流检测信号，其中，第一电阻电压和第二电阻电压中的最大电压为电感的电感电流经过的检测电阻的电压，电流检测信号用于指示电感电流的大小。
具体来说，在Buck-Boost电路降压转换的电感充电阶段，电感电流可以流经第一检测电阻和第二检测电阻，此时第一电阻电压和第二电阻电压皆为最大电压。在Buck-Boost 电路降压转换的电感续流阶段，电感电流只流经第二检测电阻，并不流经第一检测电阻，此时第二电阻电压为最大电压。在Buck-Boost电路升压转换的电感充电阶段，电感电流可以流经第一检测电阻，但不流经第二检测电阻，此时第一电阻电压为最大电压。在Buck-Boost电路升压转换的电感续流阶段，电感电流可以流经第一检测电阻和第二检测电阻，此时第一电阻电压和第二电阻电压皆为最大电压。
由此可见，无论Buck-Boost电路进行升压转换还是降压转换，第一检测电阻和第二检测电阻中都存在至少一个检测电阻可以传输电感电流，因此，检测电路可以根据第一电阻电压和第二电阻电压中的最大电压输出电流检测信号，以使该电流检测信号能够指示电感电流的大小。
在本申请实施例中，第一检测电阻的一端可以与Buck-Boost电路的高电势输入端连接，也可以与Buck-Boost电路的低电势输入端连接。第二检测电阻的一端可以与Buck-Boost电路的高电势输出端连接，也可以与Buck-Boost电路的低电势输出端连接。本申请实施例对此并不多作限制。
其中，在第一检测电阻的一端与Buck-Boost电路的低电势输入端连接时，第一桥臂的一端通过第一检测电阻与Buck-Boost电路的低电势输入端连接，第一桥臂的另一端与Buck-Boost电路的高电势输入端连接。第二桥臂的一端通过第二检测电阻与Buck-Boost电路的低电势输出端连接时，第二桥臂的另一端与Buck-Boost电路的高电势输出端连接。
在此情况下，第一检测电阻两端的电势和第二检测电阻两端的电势都比较低，两个检测电阻两端的共模电压(对地电压)较低，有利于提高检测电路对电阻电压的采样精度。
一般来说，Buck-Boost电路还可以包括输入电容，输入电容可以对Buck-Boost电路的输入电压进行滤波。在本申请实施例中，输入电容的一端与Buck-Boost电路的高电势输入端连接，输入电容的另一端与Buck-Boost电路的低电势输入端连接，第一检测电阻位于输入电容和第一桥臂之间。
具体来说，由于输入电容具有滤波的作用，若第一检测电阻位于Buck-Boost电路的低电势输入端和输入电容之间，也就是输入电容通过第一检测电阻与Buck-Boost电路的低电势输入端连接，则经过第一检测电阻的电流将会是电感电流的均值电流，该实现方式不利于检测实时的电感电流。而在第一检测电阻位于第一桥臂和输入电容之间时，输入电容的滤波作用并不会影响经过第一检测电阻的电流，也就是说，经过第一检测电阻的电流可以是实时的电感电流，因此有利于通过第一检测电阻的电阻电压检测到实时的电感电流。
类似的，Buck-Boost电路还可以包括输出电容，输出电容的一端与Buck-Boost电路的高电势输出端连接，输出电容的另一端与Buck-Boost电路的低电势输出端连接，第二检测电阻位于输出电容和第二桥臂之间。采用该实现方式，有利于通过第二检测电阻的电阻电压检测到实时的电感电流。
接下来，对检测电路作进一步的示例性说明。本申请实施例中，检测电路还可以包括第一采样电路、第二采样电路和合路电路，其中，第一采样电路分别与第一检测电阻的两端和合路电路连接，第二采样电路分别与第二检测电阻的两端和合路电路连接。第一采样电路，可以根据第一检测电阻的第一电阻电压，向合路电路输出第一采样信号，第一采样信号的电压与第一电阻电压之间满足正相关关系；第二采样电路，可以根据第二检测电阻的第二电阻电压，向合路电路输出第二采样信号，第二采样信号的电压与第二电阻电压之间满足正相关关系；合路电路，可以根据第一采样信号和第二采样信号中的最大电压输出 电流检测信号。
在本申请实施例中，第一采样信号和第一电阻电压之间，以及第二采样信号和第二电阻电压之间应满足相同的正相关关系，以确保通过对比第一采样信号和第二采样信号，可以确定第一电阻电压和第二电阻电压之间的相对大小关系。
示例性的，第一采样电路可以包括第一运放电路，该第一运放电路的一个输入端与第一检测电阻的一端连接，第一运放电路的另一个输入端与第一检测电阻的另一端连接，第一运放电路的输出端用于输出第一采样信号。一般来说，第一采样信号的电压为正。因此，第一运放电路的正向输入端可以与第一检测电阻的高电势端连接，第一运放电路的反向输入端可以与第一检测电阻的低电势端连接。
示例性的，第二采样电路可以包括第二运放电路，该第二运放电路的一个输入端与第二检测电阻的一端连接，第二运放电路的另一个输入端与第二检测电阻的另一端连接，第二运放电路的输出端用于输出第二采样信号。一般来说，第二采样信号的电压为正。因此，第二运放电路的正向输入端可以与第二检测电阻的高电势端连接，第二运放电路的反向输入端可以与第二检测电阻的低电势端连接。
示例性的，合路电路可以包括第一二极管和第二二极管，其中，第一二极管的阳极与第一采样电路连接，第二二极管的阳极与第二采样电路连接，第一二极管的阴极和第二二极管的阴极通过第一连接点连接，该第一连接点可以输出电流检测信号。
具体来说，由于第一二极管的阴极和第二二极管的阴极连接，因此阳极电压较大的二极管将会将阳极电压较低的二极管截止。而本申请实施例中，第一二极管的阳极电压即为第一采样信号的电压，第二二极管的阳极电压即为第二采样信号的电压。因此，在第一采样信号的电压大于第二采样信号的电压时，第一二极管导通，使得第一连接点的电压为第一采样信号的电压。同理，在第二采样信号的电压大于第一采样信号的电压时，第二二极管导通，使得第一连接点的电压为第二采样信号的电压。
由此可见，第一采样点的电压为第一采样信号和第二采样信号中的较大电压，而第一采样信号和第二采样信号分别与第一电阻电压和第二电阻电压之间存在正相关关系，因此，第一采样信号和第二采样信号中的较大电压便与电感电流之间存在着正相关关系，第一采样点的电压便可以作为电流检测信号指示电感电流的大小。
为了进一步提高电感电流的检测精度，在一种可能的实现方式中，合路电路还可以包括第三运放电路和第四运放电路。其中，第四运放电路的一个输入端与第二采样电路连接，用于接收第二采样信号，第四运放电路的另一个输入端与第二二极管的阴极连接，第四运放电路的输出端与第二二极管的阳极连接，第三运放电路的一个输入端与第一采样电路连接，用于接收所第一采样信号，第三运放电路的另一个输入端与第一二极管的阴极连接，第三运放电路的输出端与第一二极管的阳极连接。
以第三运放电路为例，第三运放电路的两个输入端的电压分别为第一采样信号的电压和第一二极管的阴极电压。根据运算放大电路的“虚短”特性，即第三运放电路的两个输入端的电压相等，因此可以保持第一采样信号的电压和第一二极管的阴极电压相等，从而起到了电压跟随的效果。同理，第四运放电路可以保持第二采样信号的电压和第二二极管的阴极电压相等。从而使得第一连接点的电压可以与第一采样信号或第二采样信号的电压保持相等，由于进一步提高电流检测精度。
在一种可能的实现方式中，合路电路还可以包括接地电阻，接地电阻的一端与第一连 接点连接，接地电阻的另一端接地。通过设置接地电阻，可以防止第一连接点的电压被锁死在0V。
应理解，本申请实施例可以适用于多种类型的Buck-Boost电路。例如，Buck-Boost电路可以包括多个第一桥臂、多个第二桥臂和多个电感，多个第一桥臂并联，多个第二桥臂并联，多个电感分别与多个第一桥臂和多个第二桥臂一一对应连接，其中，每个电感的一端与每个电感对应的第一桥臂连接，每个电感的另一端与每个电感对应的第二桥臂连接。在此情况下，检测电路可以通过第一检测电阻和第二检测电阻检测多个电感的电感电流之和。
第二方面，本申请实施例提供一种电压转换器，主要包括控制器和如第一方面中任一项所提供的电压转换电路。其中，控制器可以控制电压转换电路进行电压转换。
第三方面，本申请实施例提供一种电子设备，主要包括如第二方面所提供的电压转换器。
附图说明
图1为一种电压转换器的结构示意图；
图2a为一种Buck-Boost电路的结构示意图；
图2b至2e为一种Buck-Boost电路的开关状态示意图；
图3为本申请实施例提供的一种电压转换器的结构示意图；
图4为本申请实施例提供的一种Buck-Boost电路的结构示意图；
图5a为本申请实施例提供的检测电阻中的电流变化示意图；
图5b为本申请实施例提供的Buck-Boost电路的开关状态示意图；
图5c为本申请实施例提供的Buck-Boost电路的开关状态示意图；
图6a为本申请实施例提供的检测电阻中的电流变化示意图；
图6b为本申请实施例提供的Buck-Boost电路的开关状态示意图；
图6c为本申请实施例提供的Buck-Boost电路的开关状态示意图；
图7为本申请实施例提供的一种检测电路的结构示意图；
图8为本申请实施例提供的一种合路电路的结构示意图。
具体实施方式
为了使本申请的目的、技术方案和优点更加清楚，下面将结合附图对本申请作进一步地详细描述。需要说明的是，在本申请的描述中“至少一个”是指一个或多个，其中，多个是指两个或两个以上。鉴于此，本发明实施例中也可以将“多个”理解为“至少两个”。“和/或”，描述关联对象的关联关系，表示可以存在三种关系，例如，A和/或B，可以表示：单独存在A，同时存在A和B，单独存在B这三种情况。另外，字符“/”，如无特殊说明，一般表示前后关联对象是一种“或”的关系。另外，需要理解的是，在本申请的描述中，“第一”、“第二”等词汇，仅用于区分描述的目的，而不能理解为指示或暗示相对重要性，也不能理解为指示或暗示顺序。
需要指出的是，本申请实施例中“连接”可以理解为电连接，两个电学元件连接可以 是两个电学元件之间的直接或间接连接。例如，A与B连接，既可以是A与B直接连接，也可以是A与B之间通过一个或多个其它电学元件间接连接，例如A与B连接，也可以是A与C直接连接，C与B直接连接，A与B之间通过C实现了连接。在一些场景下，“连接”也可以理解为耦合，如两个电感之间的电磁耦合。总之，A与B之间连接，可以使A与B之间能够传输电能。
下面对本申请作进一步地详细描述。
Buck-Boost电路是一种常见的电压(电流)转换电路，既可以实现降压转换，也可以实现升压转换，因此可以应用在诸多电力系统内的电压转换器中。图1示例性示出了一种电压转换器，如图1所示，电压转换器10主要包括Buck-Boost电路11、控制器12和检测电路13。其中，Buck-Boost电路11分别与控制器12和检测电路13连接，控制器12与检测电路13连接。具体来说：
Buck-Boost电路11
Buck-Boost电路11也常被称为升降压转换电路。具体来说，在Buck-Boost电路11进行降压转换时，Buck-Boost电路11的输入电压Vi大于输出电压Vo。在Buck-Boost电路11进行升压转换时，Buck-Boost电路的输入电压Vi小于输出电压Vo。
由于Buck-Boost电路11既可以实现降压转换，又可以实现升压转换，使得具有Buck-Boost电路11的电压转换器10在诸多电力系统中存在着广泛的应用。例如，电压转换器10可以是电动/混合动力汽车的电源管理系统中的电力电子变流器，也可以是光伏发电系统中的电池管理系统(battery management system，BMS)，还可以是通信电源供电系统中的直流配电单元等，本申请对此不再一一列举。
示例性的，图2a为一种Buck-Boost电路结构示意图。如图2a所示，该Buck-Boost电路11具有H桥结构。Buck-Boost电路11主要包括桥臂111、桥臂112和电感113，且电感13位于桥臂111和桥臂112之间。
在Buck-Boost电路11中，桥臂111和桥臂112主要由多个开关管构成，通过改变各个开关管的导通或断开，可以调节电感113的充电或放电。示例性的，如图2a所示，桥臂111包括开关管S1和开关管S2，开关管S1的第二电极与开关管S2的第一电极连接，开关管S1的第一电极和开关管S2的第二电极可以接收输入电压V i。桥臂112包括开关管S3和开关管S4，开关管S3的第二电极与开关管S4的第一电极连接，开关管S3的第一电极和开关管S4的第二电极可以输出输出电压V o。电感113的一端与开关管S1的第二电极连接，电感13的另一端与开关管S4的第二电极连接。
通常，Buck-Boost电路11还可以包括输入电容C i。其中，输入电容C i的一端与Buck-Boost的电路11的高电势输入端连接，输入电容C i的另一端与Buck-Boost的电路11的低电势输入端连接。输入电容C i可以对输入电压V i进行滤波，降低输入电压V i的纹波。
此外，Buck-Boost电路11还可以包括输出电容C o。输入电容C o的一端与Buck-Boost的电路11的高电势输出端连接，输入电容C o的另一端与Buck-Boost的电路11的低电势输出端连接。输出电容C o可以对输出电压V o进行滤波，使Buck-Boost电路11还可以连续输出稳定的输出电压V o。
基于图2a所示的Buck-Boost电路11，可以通过控制开关管S1至开关管S4周期性的导通与断开，使Buck-Boost电路11实现电压转换。
在进行降压转换时，每个周期主要包括以下阶段：
电感充电阶段，Buck-Boost电路11中各个开关管的状态可以如图2b所示，其中开关管S1和开关管S3导通，开关管S2和开关管S4断开。
图2b中的箭头示出了电流的传输方向，如图2b所示，电流从Buck-Boost电路11的高电势输入端输入，依次流经开关管S1、电感113和开关管S3，并通过开关管S3的第一电极从Buck-Boost电路11的高电势输出端输出，回流的电流从Buck-Boost电路11的低电势输出端输入，并从Buck-Boost电路11的低电势输入端输出。
此时，电感113靠近开关管S1的一端为高电势，其电势等于Buck-Boot电路11的高电势输入端的电势。电感113靠近开关管S3的另一端为低电势，其电势等于Buck-Boot电路11的高电势输出端的电势。由于Buck-Boot电路11的低电势输入端和低电势输出端等电势连接，因此电感113的电压为V i-V o。
其中，电感113电压可以理解为电感113靠近开关管S1的一端的电势，减去电感113靠近开关管S3的另一端的电势后得到的电势差。为了便于表述，后续实施例中电感113电压同理，对此不再赘述。
流经电感113的电流也可以称为电感电流i L。由于电感电流i L无法瞬间增大，因此在开关管S1和开关管S3导通后电感电流i L逐渐增大，又由于在降压转换时输入电压V i大于输出电压V o，因此该过程中电感113电压V i-V o大于0，电感113充电。
电感续流阶段，Buck-Boost电路11中各个开关管的状态可以如图2c所示，其中开关管S1断开，开关管S2导通，开关管S3保持导通，开关管S4保持断开。
图2c中的箭头示出了电流的传输方向，如图2c所示，电流从电感113靠近开关管S3的另一端输出，并经开关管S3的第一电极从Buck-Boost电路11的高电势输出端输出。回流的电流从Buck-Boost电路11的低电势输出端输入，并经开关管S2回流至电感113靠近开关管S1的一端。
此时，电感113靠近开关管S1的一端为低电势，其低电势等于Buck-Boot电路11的低电势输出端的电势。电感113靠近开关管S3的另一端为高电势，其电势等于Buck-Boot电路11的高电势输出端的电势。进而可以得到，电感113的电压为-V o。
由于电感电流i L无法瞬间归零，因此在开关管S1断开后电感电流i L逐渐降低。又由于此时电感113的电压为-Vo，因此电感113将开始放电，该过程也可以称为电感113续流。电感113输出的电感电流i L通过开关管S3输出。
假设电感充电阶段时长和电感放电阶段的时长相等，皆为t，则根据伏秒平衡原则可知：(V i-V o)t-V ot＝0，进而可得V o＝V i/2。因此，经过上述电感充电阶段和电感放电阶段，可以使Buck-Boost电路11实现降压转换。
在进行升压转换时，每个周期主要包括以下阶段：
电感充电阶段，Buck-Boost电路11中各个开关管的状态可以如图2d所示，其中开关管S1和开关管S4导通，开关管S2和开关管S3断开。
图2d中的箭头示出了电流的传输方向，如图2d所示，电流从开关管S1的第一电极输入，依次流经开关管S1、电感113和开关管S4，并从Buck-Boost电路11的低电势输入端输出。
此时，电感113靠近开关管S1的一端为高电势，其电势等于Buck-Boot电路11的高电势输入端的电势。电感113靠近开关管S3的另一端为低电势，其电势等于Buck-Boot 电路11的低电势输入端的电势。因此，电感113的电压为V i。
在此阶段内，电感113充电，输出电容C o放电，输出电压V o等于输出电容C o的电压。
电感放电阶段，Buck-Boost电路11中各个开关管的状态可以如图2e所示，其中开关管S3导通，开关管S4断开，开关管S1保持导通，开关管S2保持断开。
图2e中的箭头示出了电流的传输方向，如图2e所示，电流从Buck-Boot电路11的高电势输入端输入，经电感113传输后，通过开关管S3从Buck-Boot电路11的高电势输出端输出。回流的电流从Buck-Boost电路11的低电势输出端输入，并从Buck-Boost电路11的低电势输入端输出。
此时，电感113靠近开关管S1的一端为低电势，电势等于Buck-Boot电路11的高电势输出端的电势。电感113靠近开关管S3的一端为高电势，其电势等于Buck-Boot电路11的高电势输出端的电势。由于Buck-Boot电路11的低电势输入端和低电势输出端等电势连接，因此电感113的电压为V i-V o。
由于电感电流i L无法瞬间归零，因此在开关管S1和开关管S3导通后电感电流i L逐渐降低，又由于在升压转换时输入电压V i小于输出电压V o，因此该过程中电感113电压V i-V o小于0，电感113放电。
假设电感充电阶段时长和电感放电阶段的时长相等，皆为t，则根据伏秒平衡原则可知：V it+(V i-V o)t＝0，进而可得V o＝2V i。因此，经过上述电感充电阶段和电感放电阶段，可以使Buck-Boost电路11实现升压转换。
控制器12
控制器12可以分别为开关管S1至S4提供相同或不同的控制信号，从而可以分别控制开关管S1至S4的导通与断开，进而使Buck-Boost电路11可以实现上述电压转换。示例性的，控制器12可以是能够生成控制信号的逻辑电路，例如控制器12可以是通用中央处理器(central processing unit，CPU)，通用处理器，数字信号处理(digital signal processing，DSP)，专用集成电路(application specific integrated circuits，ASIC)，现场可编程门阵列(field programmable gate array，FPGA)、微控制器(microcontroller unit，MCU)，或者其它可编程逻辑器件、晶体管逻辑器件、硬件部件或者其任意组合。
检测电路13
检测电路13可以检测Buck-Boost电路11的工作状态，并将检测到的工作状态信息反馈给控制器12，使控制器12可以根据Buck-Boost电路11的工作状态信息调节提供给开关管S1至开关管S4的控制信号，也就是说，控制器12可以通过检测电路13实现对Buck-Boost电路11的闭环控制。
在Buck-Boost电路11的一些应用场景中，往往需要检测电路13检测Buck-Boost电路11中的电感电流i L。例如，检测电路13检测到的电感电流i L可以用于闭环控制。控制器12可以根据检测电路13检测到的电感电流i L调节提供给开关管S1至S4的控制信号，从而实现闭环控制。
此外，检测电路13检测到的电感电流还可以用于过流保护(over current protection，OCP)。例如，控制器12可以在检测电路13检测到的电感电流i L超过电流阈值时，控制Buck-Boost电路11停止对输入电压V i进行电压转换。
可以理解，以上仅为两种常见的电感电流i L的应用场景，本申请对其它可能的应用场景不再一一列举。
在目前的一些检测方案中，检测电路13主要包括电流传感器，该电流传感器为一种与电感113串联的霍尔元件。当电感113充电或放电时，便会引起电流传感器的输出信号变化。控制器12便可以根据电流传感器的输出信号确定当前的电感电流i L的大小。
然而，目前多数电流传感器的成本较高，不利于节省电压转换器10的成本。而且，由于电流传感器基于霍尔效应对电感电流i L进行检测，使得电流传感器的检测时延较大，限制了电感电流i L在部分场景中的应用。例如，在OCP场景中，由于电流传感器的检测时延较大，有可能使控制器12无法在电感电流i L过大时立即控制Buck-Boost电路11停止工作，增大了Buck-Boost电路11损坏的风险。
有鉴于此，本申请实施例提供一种检测电路，该检测电路中包括第一检测电阻和第二检测电阻。第一检测电阻和第二检测电阻可以接入Buck-Boost电路，无论Buck-Boost电路处于图2b至图2e所示的任一状态，电感电流i L皆可以流过第一检测电阻和第二检测电阻中的至少一个。因此，检测电路可以在第一检测电阻和第二检测电阻的基础上实现对电感电流i L的检测。
图3示例性示出了本申请实施例所提供的一种电压转换器结构示意图，如图3所示，电压转换器30主要包括Buck-Boost电路31和检测电路33。在一种可能的实现方式中，电压转换器30还可以包括控制器32，控制器32可以控制Buck-Boost电路31进行电压转换。此外，控制器32也可以接收检测电路33提供的电流检测信号，控制器32的具体实现方式与前述控制器12类似，对此不赘述。
如图3所示，Buck-Boost电路31具有H桥结构，包括桥臂311、桥臂312、电感313，电感313位于桥臂311和桥臂312之间。由图3可见，Buck-Boost电路31中的H桥结构主要由电感313、桥臂311和桥臂312构成，且该H桥结构与Buck-Boost电路11中的H桥结构(主要由电感113、桥臂111和桥臂112构成)类似，重复之处不再赘述。
在本申请实施例中，开关管S1至开关管S4可以是继电器、金属氧化物半导体场效应晶体管(metal oxide semiconductor field effect transistor，MOSFET)，双极结型管(bipolar junction transistor，BJT)，绝缘栅双极型晶体管(insulated gate bipolar transistor，IGBT)等多种类型的开关管中的一种或多种，本申请实施例对此不再一一列举。
需要指出的是，图3中Buck-Boost电路31内的H桥结构仅为示例，在具体实现结构中，Buck-Boost电路31还可以具有其它类型的实现方式。例如，图4所示，桥臂311可以包括N个第一桥臂311和N个第二桥臂312，以及N个电感113(电感113-1至电感113-N)，N为大于或等于1的整数。
具体来说，开关管S11和开关管S12属于同一个第一桥臂，开关管S21和开关管S22属于同一个第一桥臂，……，开关管SN1和开关管SN2属于同一个第一桥臂。开关管S13和开关管S14属于同一个第二桥臂，开关管S23和开关管S24属于同一个第二桥臂，……，开关管SN3和开关管SN4属于同一个第二桥臂。
如图4所示，N个第一桥臂并联，N个第二桥臂并联。具体来说，开关管S11的第一电极至开关管SN1的第一电极皆与Buck-Boost电路31的高电势输入端连接，开关管S12的第一电极至开关管SN2的第二电极皆与Buck-Boost电路31的低电势输入端连接，开关 管S13的第一电极至开关管SN3的第一电极皆与Buck-Boost电路31的高电势输出端连接，开关管S14的第一电极至开关管SN4的第二电极皆与Buck-Boost电路31的低电势输出端连接。
Buck-Boost电路31中的N个电感分别与N个第一桥臂和N个第二桥臂一一对应连接，每个电感的一端与对应的第一桥臂连接，每个电感的另一端与对应的第二桥臂连接。例如图4中，电感313-1的一端与开关管S11和开关管S12所在的第一桥臂连接，电感313-1的另一端与开关管S13和开关管S14所在的第二桥臂连接。电感313-2的一端与开关管S21和开关管S22所在的第一桥臂连接，电感313-2的另一端与开关管S23和开关管S24所在的第二桥臂连接。电感313-N的一端与开关管SN1和开关管SN2所在的第一桥臂连接，电感313-N的另一端与开关管SN3和开关管SN4所在的第二桥臂连接。
为了便于理解，本申请实施例接下来以图3所示的Buck-Boost电路31为例进行说明。需要指出的是，本申请实施例同样可以适用于Buck-Boost电路31包括两个及两个以上数量的电感313的场景。
如图3所示，检测电路33包括检测电阻R1和检测电阻R2。其中，检测电阻R1的一端与Buck-Boost电路31的一个输入端连接，检测电阻R1的另一端与桥臂311的一端连接，桥臂311的另一端与Buck-Boost电路31的另一个输入端连接。检测电阻R2的一端与Buck-Boost电路31的一个输出端连接，检测电阻R2的另一端与桥臂312的一端连接，桥臂312的另一端与Buck-Boost电路31的另一个输出端连接。
其中，Buck-Boost电路31的两个输入端中，一个为高电势输入端，另一个为低电势输入端，高电势输入端减去低电势输入端之后的电势差即为输入电压V i。Buck-Boost电路31的两个输出端中，一个为高电势输出端，另一个为低电势输出端，高电势输出端减去低电势输出端之后的电势差即为输出电压V o。
在本申请实施例中，“检测电阻R1的一端与Buck-Boost电路31的一个输入端连接，检测电阻R1的另一端与桥臂311的一端连接”，可以理解为桥臂311中开关管S1的第一电极通过检测电阻R1与Buck-Boost电路31的高电势输入端连接。在此情况下开关管S2的第二电极与Buck-Boost电路31的低电势输入端连接。
“检测电阻R1的一端与Buck-Boost电路31的一个输入端连接，检测电阻R1的另一端与桥臂311的一端连接”，也可以理解为桥臂311中开关管S2的第二电极通过检测电阻R1与Buck-Boost电路31的低电势输入端连接。在此情况下，桥臂311中开关管S1的第一电极与Buck-Boost电路31的高电势输入端连接。
检测电阻R2分别与Buck-Boost电路31的一个输出端和桥臂312的一端之间的连接关系与之同理，对此不再赘述。
其中，在检测电阻R1的一端与Buck-Boost电路31的低电势输入端连接，检测电阻R2的一端与Buck-Boost电路31的低电势输出端连接的情况下，检测电阻R1两端的电势和检测电阻R2两端的电势都比较低，两个检测电阻两端的共模电压(对地电压)较低，有利于提高检测电路33对电阻电压的采样精度。
在本申请实施例中，如图3所示，Buck-Boost电路31还可以包括输入电容C i，输入电容C i的一端与Buck-Boost电路31的高电势输入端连接，输入电容C i的另一端与Buck-Boost电路31的低电势输入端连接。
在此情况下，检测电阻R1可以位于输入电容Ci和桥臂311之间。例如图3中，检测 电阻R1的一端还与输入电容Ci的另一端连接，检测电阻R1的另一端与桥臂311中开关管S2的第二电极连接。
具体来说，由于输入电容C i具有滤波的作用，若检测电阻R1位于Buck-Boost电路31的低电势输入端和输入电容C i之间，也就是输入电容C i通过检测电阻R1与Buck-Boost电路31的低电势输入端连接，则经过检测电阻R1的电流将会是电感电流i L的均值电流。虽然在此情况下可以通过检测电阻R1的电阻电压检测到电感电流i L的均值电流，但该实现方式不利于检测实时的电感电流i L。
而在检测电阻R1位于桥臂311和输入电容C i之间时，输入电容C i的滤波作用并不会影响经过检测电阻R1的电流，也就是说，经过检测电阻R1的电流可以是实时的电感电流i L，因此有利于通过检测电阻R1的电阻电压检测到实时的电感电流i L。
类似的，Buck-Boost电路31还可以包括输出电容C o，输出电容C o的一端与Buck-Boost电路31的高电势输出端连接，输出电容C o的另一端与Buck-Boost电路31的低电势输出端连接。
在此情况下，检测电阻R2可以位于桥臂312和输出电容C o之间。例如图3中，和检测电阻R2的一端还与输出电容C o的另一端连接，检测电阻R1的另一端与桥臂312中开关管S4的第二电极连接。采用该实现方式，有利于通过检测电阻R2的电阻电压检测到实时的电感电流i L，具体不再赘述。
基于上述检测电阻R1和检测电阻R2，不论Buck-Boost电路31进行升压转换还是降压转换，电感电流i L都可以经过检测电阻R1和检测电阻R2中的至少一个，使得检测电路33可以通过检测电阻R1和检测电阻R2的电阻电压检测电感电流i L的大小。
如图3所示，检测电路33分别与检测电阻R1和检测电阻R2连接。具体来说，检测电路33分别与检测电阻R1的两端和检测电阻R2的两端连接。检测电路33可以分别检测检测电阻R1的电阻电压V R1和检测电阻R2的电阻电压V R2。
检测电路33进而可以根据电阻电压V R1和电阻电压V R2中的最大电压，输出电流检测信号V a。其中，电阻电压V R1和电阻电压V R2中的最大电压可以是检测电阻R1和检测电阻R2中有电感电流i L经过的检测电阻的电压。因此，根据电阻电压V R1和电阻电压V R2中的最大电压输出的电流检测信号V a可以指示经过检测电阻R1和/或检测电阻R2的电感电流i L的大小。
需要指出的是，检测电阻R1和检测电阻R2的阻值相等，基于检测电阻R1和检测电阻R2在Buck-Boost电路31中的位置，电阻电压V R1和电阻电压V R2中的最大电压与电感电流i L之间始终保持着等比例关系，且比值即为检测电阻R1和检测电阻R2的阻值。
接下来，对Buck-Boost电路31进行电压转换时电感电流i L分别与检测电阻R1和检测电阻R2之间的关系作进一步的示例性说明。
降压转换
示例性的，如图5a所示，为降压转换过程中检测电阻R1和检测电阻R2的电流变化示意图。其中，降压转换的周期为T1，即每隔T1时间，Buck-Boost电路31可以完成一次降压转换。图5a中，每个T1包括t1和t2两个时间段，其中，t1表示降压转换中的电感充电阶段，t2表示降压转换中的电感续流阶段。i R2表示流经检测电阻R2的电流，i R1表示流经检测电阻R1的电流。
电感充电阶段：如前所述，请参考图5b，在降压转换的电感充电阶段，开关管S1和开关管S3导通，开关管S2和开关管S4断开，电流从Buck-Boost电路31的高电势输入端输入，依次流经开关管S1、电感113和开关管S3，并通过开关管S3的第一电极从Buck-Boost电路31的高电势输出端。回流的电流从Buck-Boost电路31的低电势输出端输入，依次流经检测电阻R2和检测电阻R1，并从Buck-Boost电路31的低电势输入端输出。
在此阶段内，电感313、检测电阻R2和检测电阻R1依次串联，因此流经检测电阻R1的电流i R1和流经检测电阻R2的电流i R2等于电感电流i L。在降压转换的电感充电阶段，电感电流i L逐渐增大，因此如图5a所示，在时间段t1内，流经检测电阻R1的电流i R1和流经检测电阻R2的电流i R2也逐渐增大。
由于流经检测电阻R1的电流i R1和流经检测电阻R2的电流i R2等于电感电流i L，且检测电阻R1和检测电阻R2的阻值相等，因此在降压转换的电感充电阶段内电阻电压V R1和电阻电压V R2相等，电阻电压V R1和电阻电压V R2中的最大电压即为电阻电压V R1和电阻电压V R2，且电阻电压V R1和电阻电压V R2与电感电流i L之间的比值即为检测电阻R1和检测电阻R2的阻值。
电感续流阶段：如前所述，请参考图5c，在降压转换的电感续流阶段，开关管S1断开，开关管S2导通，开关管S3保持导通，开关管S4保持断开。电流从电感313靠近开关管S3的一端输出，经开关管S3传输后通过Buck-Boost电路31的高电势输出端输出。回流的电流从Buck-Boost电路31的低电势输出端输入，电流依次流经检测电阻R2和开关管S2，从而回流至电感313靠近开关管S1的一端。
在此阶段内，电感313和检测电阻R2串联，因此流经检测电阻R2的电流i R2等于电感电流i L。在电感续流阶段，电感电流i L逐渐降低，因此如图5a所示，在时间段t2内，流经检测电阻R2的电流i R2也逐渐降低。由于在降压转换的电感续流阶段内，检测电阻R1中并无电流经过，因此如图5a所示，在时间段t2内检测电阻R1的电流i R1为零。
由于流经检测电阻R2的电流i R2等于电感电流i L，检测电阻R1的电流i R1为零，因此电阻电压V R2大于电阻电压V R1，即电阻电压V R1和电阻电压V R2中的最大电压为电阻电压V R2，且电阻电压V R2与电感电流i L之间的比值为检测电阻R2的阻值。
由此可见，在降压转换的电感充电阶段和电感续流阶段，电阻电压V R1和电阻电压V R2中的最大电压始终与电感电流i L之间保持着等比例关系，且比值即为检测电阻R2的阻值。
升压转换
示例性的，如图6a所示，为升压转换过程中检测电阻R1和检测电阻R2的电流变化示意图。其中，升压转换的周期为T2，即每隔T2时间，Buck-Boost电路31可以完成一次升压转换。图6a中，每个T2包括t3和t4两个时间段，其中，t3表示升压转换的中的电感充电阶段，t4表示升压转换中的电感续流阶段。i R2表示流经检测电阻R2的电流，i R1表示流经检测电阻R1的电流。
电感充电阶段：如前所述，请参考图6b，在升压转换的电感充电阶段，开关管S1和开关管S4导通，开关管S2和开关管S3断开，电流从Buck-Boost电路31的高电势输入端输入，依次流经开关管S1、电感113、开关管S4和检测电阻R1后，从Buck-Boost电路11的低电势输入端输出。
在此阶段内，电感313和检测电阻R1串联，因此流经检测电阻R1的电流i R1等于电 感电流i L。在升压转换的电感充电阶段，电感电流i L逐渐增大，因此如图6a所示，在时间段t3内，流经检测电阻R1的电流i R1也逐渐增大。由于在升压转换的电感充电阶段内，检测电阻R2中并无电流经过，因此如图6a所示，在时间段t3内检测电阻R2的电流i R2为零。
由于流经检测电阻R1的电流i R1等于电感电流i L，检测电阻R2的电流i R2为零，因此电阻电压V R1大于电阻电压V R2，电阻电压V R1和电阻电压V R2中的最大电压为电阻电压V R1，且电阻电压V R1与电感电流i L之间的比值为检测电阻R1的阻值。
电感续流阶段：如前所述，请参考图6c，在升压转换的电感续流阶段，开关管S3导通，开关管S4断开，开关管S1保持导通，开关管S2保持断开。电流从Buck-Boost电路31的高电势输入端输入，依次流经开关管S1、电感313和开关管S3，并开关管S3从Buck-Boost电路31的高电势输出端输出。回流的电流从Buck-Boost电路31的低电势输出端输入，依次流经检测电阻R2和检测电阻R1，并通过Buck-Boost电路31的低电势输入端输出。
在此阶段内，电感313、检测电阻R2和检测电阻R1依次串联，因此流经检测电阻R1的电流i R1和流经检测电阻R2的电流i R2等于电感电流i L。在升压转换的电感续流阶段，电感电流i L逐渐降低，因此如图6a所示，在时间段t4内，流经检测电阻R1的电流i R1和流经检测电阻R2的电流i R2也逐渐降低。
由于流经检测电阻R1的电流i R1和流经检测电阻R2的电流i R2等于电感电流i L，且检测电阻R1和检测电阻R2的阻值相等，因此在降压转换的电感充电阶段内电阻电压V R1和电阻电压V R2相等，电阻电压V R1和电阻电压V R2中的最大电压即为电阻电压V R1和电阻电压V R2，且电阻电压V R1和电阻电压V R2与电感电流i L之间的比值即为检测电阻R1和检测电阻R2的阻值。
由此可见，在升压转换的电感充电阶段和电感续流阶段，电阻电压V R1和电阻电压V R2中的最大电压始终与电感电流i L之间保持着等比例关系，且相关系数即为检测电阻R1的阻值。
综上，无论是在降压转换过程中，还是在升压转换过程中，电阻电压V R1和电阻电压V R2中的最大电压始终保持与电感电流i L之间的等比例关系，且该相关系数为检测电阻R1和检测电阻R2的阻值。
因此，检测电路33进而可以根据电阻电压V R1和电阻电压V R2中的最大电压输出电流检测信号V a，使电流检测信号V a可以指示经过检测电阻R1和/或检测电阻R2的电感电流i L。
在本申请实施例中，由于检测电阻R1和/或检测电阻R2的电阻电压可以随电感电流i L实时变化，因此检测电路33的检测时延较短。而且，相较于电流传感器，检测电阻R1和检测电阻R2的成本更低，因此本申请实施例还有利于降低电压转换器30的成本。
如前所述，检测电路33可以根据电阻电压V R1和电阻电压V R2中的最大电压输出电流检测信号V a。示例性的，电流检测信号V a可以是一种电压信号，电流检测信号V a的电压大小与电阻电压V R1和电阻电压V R2中的最大电压之间存在一一对应关系。由于电阻电压V R1和电阻电压V R2中的最大电压与电感电流i L之间存在着固定的等比例关系，因此也可以认为电流检测信号V a的电压大小与电感电流i L的大小之间存在一一对应关系，进而， 为电流检测信号V a的电压大小可以指示电感电流i L的大小。
对于电流检测信号V a的接收端(如控制器32)而言，电流检测信号V a的电压大小与电感电流i L之间的一一对应关系可以是已知的或可知的，使得电流检测信号V a的接收端可以根据接收到的电压检测信号V a的电压大小，和电流检测信号V a的电压大小与电感电流i L之间的相关关系确定电感电流i L的大小。
例如，电感电流i L与电阻电压V R1和电阻电压V R2中的最大电压V max之间满足以下关系：
V max＝i L*R  (公式一)
其中，R表示检测电阻R1和检测电阻R2的阻值。
电流检测信号V a与最大电压V max之间的一一对应关系满足以下公式：
V a＝aV max+b  (公式二)
其中，a和b为任意常数。
综合公式一和公式二可见，电流检测信号V a与电感电流i L之间的一一对应关系满足以下公式：
V a＝a i L*R+b  (公式三)
对于电流检测信号V a的接收端(如控制器32)而言，公式三所示的一一对应关系可以是已知的，且a、R和b的取值也可以是已知的。接收端在接收到电流检测信号V a后，便可以根据电流检测信号V a的电压大小，以及公式三所示的一一对应关系得到电感电流i L的大小。
为了便于理解，本申请实施例接下来以电流检测信号V a的电压大小与电阻电压V R1和电阻电压V R2中的最大电压之间一一对应关系为如公式三所示的正相关关系为例进行说明，其中a大于0。其它相关关系下的应用场景，可以在本申请实施例后续说明的基础上，经适应性调整后得到，也应包含于本申请实施例之中。
可以理解，以上示例皆是以Buck-Boost31电路中仅存在一个电感313的场景为例进行说明的。在Buck-Boost电路31中存在多个电感313(如图4所示)时，电流检测信号V a所指示的电感电流i L的大小，应为Buck-Boost电路31中存在充放电过程的一个或多个电感313的电感电流之和。
接下来，本申请实施例通过以下示例对检测电路33作进一步的示例性说明。
图3示例性示出了本申请实施例提供的一种检测电路结构示意图。如图3所示，检测电路33还包括采样电路331、采样电路332和合路电路333。其中，采样电路331分别与检测电阻R1的两端和合路电路333连接，采样电路332分别与检测电阻R2的两端和合路电路333连接。
采样电路331可以对检测电阻R1的电阻电压V R1进行采样。具体来说，采样电路331可以根据检测电阻R1的电阻电压V R1向合路电路333输出采样信号V b1。示例性的，采样信号V b1可以是电压信号，采样信号V b1的电压大小与电阻电压V R1的大小之间可以是正相关关系，也就是说，采样信号V b1的电压可以随电阻电压V R1的增大而增大，随电阻电压V R1的减小而减小。
示例性的，如图7所示，采样电路331可以包括运放电路U1，运放电路U1的一个输入端与检测电阻R1的一端连接，运放电路U1的另一个输入端与检测电阻R1的另一端连 接，运放电路U1的输出端与合路电路333连接。运放电路U1可以对检测电阻R1的电阻电压V R1进行差分采样并放大，从而可以从运放电路U1的输出端输出上述采样信号V b1。
运放电路U1的具体实现结构可以参考常见的各种运算放大电路，本申请实施例对此并不多作限制。
采样电路332可以对检测电阻R2的电阻电压V R2进行采样。具体来说，采样电路332可以根据检测电阻R2的电阻电压V R2向合路电路333输出采样信号V b2。示例性的，采样信号V b2可以是电压信号，采样信号V b2的电压大小与电阻电压V R2的大小之间可以是正相关关系，采样信号V b2的电压可以随电阻电压V R2的增大而增大，随电阻电压V R2的减小而减小。
示例性的，如图7所示，采样电路332可以包括运放电路U2，运放电路U2的一个输入端与检测电阻R2的另一端连接，运放电路U2的另一个输入端与检测电阻R2的一端连接，运放电路U2的输出端与合路电路333连接。运放电路U2可以对检测电阻R2的电阻电压V R2进行差分采样并放大，从而可以从运放电路U2的输出端输出上述采样信号V b2。
运放电路U2的具体实现结构可以参考常见的各种运算放大电路，本申请实施例对此并不多作限制。
需要指出的是，采样信号V b1与电阻电压V R1之间的正相关关系和采样信号V b2与电阻电压V R2之间的相关关系可以是同一种正相关关系，以确保采样电路331和采样电路332的采样结果不会改变电阻电压V R1与电阻电压V R2之间的相对大小关系。也就是说，上述运放电路U1和运放电路U2可以具有相同的电路结构。
例如，采样信号V b1的电压等于电阻电压V R1，采样信号V b2的电压等于电阻电压V R2。又例如，采样信号V b1的电压等于c V R1+d，采样信号V b2的电压等于c V R2+d，其中，c为大于0的常数，d为任意常数。
示例性的，运放电路U1的同向输入端(+)可以与检测电阻R1的高电势端连接，运放电路U1的反向输入端(-)可以与检测电阻R1的低电势端连接。运放电路U2的同向输入端(+)可以与检测电阻R2的高电势端连接，运放电路U1的反向输入端(-)可以与检测电阻R2的低电势端连接。
例如图3中，在检测电阻R1与Buck-Boost电路11的低电势输入端连接，检测电阻R2与Buck-Boost电路11的低电势输出端连接时，电流总是由检测电阻R1和/或检测电阻R2的靠近Buck-Boost电路11的低电势输出端的一侧，流向靠近Buck-Boost电路11的低电势输入端的一侧。
也就是说，检测电阻R1与Buck-Boost电路11的低电势输入端连接的一端为低电势端，检测电阻R1与检测电阻R2连接的另一端为高电势端。检测电阻R2与Buck-Boost电路11的低电势输出端连接的一端为高电势端，检测电阻R2与检测电阻R1连接的另一端为低电势端。
有鉴于此，如图7所示，运放电路U1的反向输入端可以与检测电阻R1靠近Buck-Boost电路11的低电势输入端的一端连接，运放电路U1的同向输入端可以与检测电阻R1靠近检测电阻R2的一端连接。运放电路U2的反向输入端可以与检测电阻R2靠近检测电阻R1的一端连接，运放电路U2的同向输入端可以与检测电阻R2靠近Buck-Boost电路11的低电势输出端的一端连接。
合路电路333可以接收检测电路331提供的采样信号V b1和采样信号V b2，进而可以根 据采样信号V b1和采样信号V b2中的最大电压输出电流检测信号V a。如前所述，采样信号V b1与电阻电压V R1之间的正相关关系和采样信号V b2与电阻电压V R2之间的相关关系可以是同一种正相关关系，因此采样信号V b1和采样信号V b2中的最大电压，与电阻电压V R1和电阻电压V R2中的最大电压之间也满足上述正相关关系。合路电路332可以根据采样信号V b1和采样信号V b2中的最大电压输出电流检测信号V a，使电流检测信号V a能够指示经过检测电阻R1和/或检测电阻R2的电感电流i L的大小。
示例性的，如图8所示，合路电路333主要包括二极管D1和二极管D2，二极管D1的阳极与采样电路331连接，可以接收采样电路331提供的采样信号V b1。二极管D2的阳极与采样电路332连接，可以接收采样电路332提供的采样信号V b2。二极管D1的阴极和二极管D2的阴极通过连接点P连接，该连接点P的电压可以作为电流检测信号V a。
具体来说，由于二极管D1和二极管D2的阴极连接，因此阳极电压较大的二极管将会将阳极电压较低的二极管截止。例如，若二极管D1的阳极电压大于二极管D2的阳极电压，则会使二极管D2截止。同样的，若二极管D2的阳极电压大于二极管D1的阳极电压，则会使二极管D1截止。
而本申请实施例中，二极管D1的阳极电压即为采样信号V b1的电压，二极管D2的阳极电压即为采样信号V b2的电压。因此，在采样信号V b1的电压大于采样信号V b2的电压时，二极管D1导通，连接点P的电压为采样信号V b1的电压。在采样信号V b2的电压大于采样信号V b1的电压时，二极管D2导通，连接点P的电压为采样信号V b2的电压。在采样信号V b1的电压等于采样信号V b2的电压时，二极管D1和二极管D2皆可以导通，连接点P的电压为采样信号V b1和采样信号V b2的电压。
由此可见，采用图8所示的合路电路333，连接点P的电压为采样信号V b1的电压和采样信号V b2的电压中的最大电压，因此连接点P的电压便可以作为上述电流检测信号V a。
在具体实现时，由于二极管本身具有一定的导通压降，有可能使连接点P的电压略低于采样信号V b1的电压和采样信号V b2的电压中的最大电压，不利于提高电流检测的准确性。有鉴于此，在一种可能的实现方式中，如图8所示，合路电路333还可以包括运放电路U3和运放电路U4。
其中，运放电路U3的一个输入端与采样电路331连接，可以接收上述采样信号V b1。运放电路U3的另一个输入端与二极管D1的阴极连接，运放电路U3的输出端与二极管D1的阳极连接。
运放电路U4的一个输入端与采样电路332连接，可以接收采样信号V b2。运放电路U4的另一个输入端与二极管D2的阴极连接，运放电路U4的输出端与二极管D2的阳极连接。
其中，运放电路U3中与运放电路U1连接的输入端可以是同向输入端，与二极管D1连接的输入端可以是反向输入端。运放电路U4中与运放电路U2连接的输入端可以是同向输入端，与二极管D2连接的输入端可以是反向输入端。采用该连接方式，有利于保持二极管D1和/或二极管D2输出的电压可以保持与采样信号V b1和/或采样信号V b1的电压同向。
以运放电路U3为例，运放电路U3的两个输入端的电压分别为采样信号V b1的电压和二极管D1的阴极电压。根据运算放大电路的“虚短”特性，即运放电路U3的两个输入端的电压相等，因此可以保持采样信号V b1的电压和二极管D1的阴极电压相等，从而起到 了电压跟随的效果。运放电路U4同理，对此不再赘述。
运放电路U3和运放电路U4的具体实现方式可以参考常见的运算放大电路，本申请实施例对此并不多作限制。
在一种可能的实现方式中，如图7所示，合路电路333还可以包括接地电阻R3。接地电阻R3的一端与连接点P连接，接地电阻R3的另一端接地。通过增设接地电阻R3，可以防止二极管D1和二极管D2与地短接，进而防止连接点P的电压被锁死在0V。
综上所述，本申请实施例中检测电路33可以基于检测电阻R1和检测电阻R2生成电流检测信号V a，从而实现对电感电流i L的检测。相较于目前基于电流传感器的检测方案，本申请实施例通过检测电阻进行采样，采样结果更加准确、迅速。值得注意的是，本申请实施例中的检测电路33可以自动适应Buck-Boost电路31的不同的电压转换过程，无需额外控制，还有利于节省控制资源。
基于相同的技术构思，本申请实施例还提供一种电子设备，主要包括本申请上述任一实施例所提供的电压转换器。示例性的，该电子设备可以是电动汽车、光伏电站、通信电源供电设备等等。
显然，本领域的技术人员可以对本申请进行各种改动和变型而不脱离本申请的保护范围。这样，倘若本申请的这些修改和变型属于本申请权利要求及其等同技术的范围之内，则本申请也意图包含这些改动和变型在内。

Claims (13)

  1. 一种电压转换电路，其特征在于，包括具有第一检测电阻和第二检测电阻的检测电路，以及H桥结构的Buck-Boost电路；
    所述Buck-Boost电路包括第一桥臂、第二桥臂和电感，所述电感位于所述第一桥臂和所述第二桥臂之间，所述第一桥臂的两端分别和所述第二桥臂的两端一一对应连接，其中，所述第一桥臂的一端通过所述第一检测电阻与所述Buck-Boost电路的一个输入端连接，所述第一桥臂的另一端与所述Buck-Boost电路的另一个输入端连接，所述第二桥臂的一端通过所述第二检测电阻与所述Buck-Boost电路的一个输出端连接，所述第二桥臂的另一端与所述Buck-Boost电路的另一个输出端连接；
    所述检测电路用于：
    分别对所述第一检测电阻的第一电阻电压和所述第二检测电阻的第二电阻电压进行电压采样；
    根据所述第一电阻电压和所述第二电阻电压中的最大电压输出电流检测信号，其中，所述第一电阻电压和所述第二电阻电压中的最大电压为所述电感的电感电流经过的检测电阻的电压，所述电流检测信号用于指示所述电感电流的大小。
  2. 根据权利要求1所述的电压转换电路，其特征在于，所述第一桥臂的一端通过所述第一检测电阻与所述Buck-Boost电路的低电势输入端连接；所述第一桥臂的另一端与所述Buck-Boost电路的高电势输入端连接；
    所述第二桥臂的一端通过所述第二检测电阻与所述Buck-Boost电路的低电势输出端连接，所述第二桥臂的另一端与所述Buck-Boost电路的高电势输出端连接。
  3. 根据权利要求1或2所述的电压转换电路，其特征在于，所述Buck-Boost电路还包括输入电容，所述输入电容的一端与所述Buck-Boost电路的高电势输入端连接，所述输入电容的另一端与所述Buck-Boost电路的低电势输入端连接，所述第一检测电阻位于所述输入电容和所述第一桥臂之间。
  4. 根据权利要求1至3中任一项所述的电压转换电路，其特征在于，所述Buck-Boost电路还包括输出电容，所述输出电容的一端与所述Buck-Boost电路的高电势输出端连接，所述输出电容的另一端与所述Buck-Boost电路的低电势输出端连接，所述第二检测电阻位于所述输出电容和所述第二桥臂之间。
  5. 根据权利要求1至4中任一项所述的电压转换电路，其特征在于，所述检测电路还包括第一采样电路、第二采样电路和合路电路，其中：
    所述第一采样电路分别与所述第一检测电阻的两端和所述合路电路连接，所述第二采样电路分别与所述第二检测电阻的两端和所述合路电路连接；
    所述第一采样电路，用于根据所述第一检测电阻的第一电阻电压，向所述合路电路输出第一采样信号，所述第一采样信号的电压与所述第一电阻电压之间满足正相关关系；
    所述第二采样电路，用于根据所述第二检测电阻的第二电阻电压，向所述合路电路输出第二采样信号，所述第二采样信号的电压与所述第二电阻电压之间满足所述正相关关系；
    所述合路电路，用于根据所述第一采样信号和所述第二采样信号中的最大电压输出所述电流检测信号。
  6. 根据权利要求5所述的电压转换电路，其特征在于，所述第一采样电路包括第一 运放电路，所述第一运放电路的一个输入端与所述第一检测电阻的一端连接，所述第一运放电路的另一个输入端与所述第一检测电阻的另一端连接，所述第一运放电路的输出端用于输出所述第一采样信号。
  7. 根据权利要求5或6所述的电压转换电路，其特征在于，所述第二采样电路包括第二运放电路，所述第二运放电路的一个输入端与所述第二检测电阻的一端连接，所述第二运放电路的另一个输入端与所述第二检测电阻的另一端连接，所述第二运放电路的输出端用于输出所述第二采样信号。
  8. 根据权利要求5至7中任一项所述的电压转换电路，其特征在于，所述合路电路包括第一二极管和第二二极管，所述第一二极管的阳极与所述第一采样电路连接，所述第二二极管的阳极与所述第二采样电路连接，所述第一二极管的阴极和所述第二二极管的阴极通过第一连接点连接，所述第一连接点用于输出所述电流检测信号。
  9. 根据权利要求8所述的电压转换电路，其特征在于，所述合路电路还包括第三运放电路和第四运放电路；
    所述第四运放电路的一个输入端与所述第二采样电路连接，用于接收所述第二采样信号；
    所述第四运放电路的另一个输入端与所述第二二极管的阴极连接，所述第四运放电路的输出端与所述第二二极管的阳极连接；
    所述第三运放电路的一个输入端与所述第一采样电路连接，用于接收所第一采样信号；
    所述第三运放电路的另一个输入端与所述第一二极管的阴极连接，所述第三运放电路的输出端与所述第一二极管的阳极连接。
  10. 根据权利要求8或9所述的电压转换电路，其特征在于，所述合路电路还包括接地电阻，所述接地电阻的一端与所述第一连接点连接，所述接地电阻的另一端接地。
  11. 根据权利要求1至10中任一项所述的电压转换电路，其特征在于，所述Buck-Boost电路包括多个第一桥臂、多个第二桥臂和多个电感；
    所述多个第一桥臂并联，所述多个第二桥臂并联，所述多个电感分别与所述多个第一桥臂和所述多个第二桥臂一一对应连接，其中，每个电感的一端与所述每个电感对应的第一桥臂连接，所述每个电感的另一端与所述每个电感对应的第二桥臂连接。
  12. 一种电压转换器，其特征在于，包括控制器和如权利要求1至11中任一项所述的电压转换电路；
    所述控制器，用于控制所述电压转换电路进行电压转换。
  13. 一种电子设备，其特征在于，包括如权利要求12所述的电压转换器。
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