Power supply system, power supply control method, and ultrasonic device

Abstract

The application discloses a power supply system, a power supply control method and an ultrasonic device, and belongs to the technical field of batteries. The power supply system comprises a control circuit, a first switch, a second switch, a first battery, a second battery, a first equalizing discharge circuit and a second equalizing discharge circuit; a first control end of the control circuit is connected with the first switch, a second control end is connected with the second switch, a first detection end is connected with the first battery, and a second detection end is connected with the second battery; the first switch is connected in series between the first battery and an output end of the power supply system, and the second switch is connected in series between the second battery and the output end of the power supply system; the first equalizing discharge circuit and the second equalizing discharge circuit are both connected in parallel between the two batteries, the first equalizing discharge circuit controls the first battery to discharge to the second battery at a constant current, and the second equalizing discharge circuit controls the second battery to discharge to the first battery at a constant current. The application reduces the voltage difference between the two batteries through mutual equalizing discharge of the two batteries in parallel connection.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a power supply system, a power control method, and an ultrasonic device. Background Technology

[0002] With the development of medical technology, the demand for batteries for desktop ultrasound equipment is increasing. Because desktop ultrasound equipment has relatively high operating power, and air transport has strict requirements on the capacity of individual batteries—if the capacity of a single battery is too large, many additional testing requirements will be needed, or it may even be prohibited from air transport—two or more batteries are usually connected in parallel to power desktop ultrasound equipment for ease of transport.

[0003] In related technologies, if two batteries are connected in parallel for power supply, and the voltage difference between them is too large, a reverse current will be generated when they are directly connected in parallel. When this current exceeds the charging protection current of the lower-voltage battery, the lower-voltage battery will enter a protection state, making it impossible to balance the voltage difference between the two batteries. Furthermore, because the load power is large, both batteries need to work together to supply the load. Therefore, when the voltage difference between the two batteries is large, the higher-voltage battery will supply power to the load independently. Its insufficient capacity will quickly trigger the discharge overcurrent protection, resulting in the inability to supply power to the load normally. Summary of the Invention

[0004] This application provides a power supply system, a power control method, and an ultrasonic device, which can solve the problem in related technologies where a large voltage difference between two batteries prevents normal power supply to the load. The technical solution is as follows:

[0005] On one hand, a power supply system is provided, the power supply system comprising: a control circuit, a first switch, a second switch, a first battery, a second battery, a first equalization discharge circuit, and a second equalization discharge circuit;

[0006] The first control terminal of the control circuit is connected to the first switch, the second control terminal of the control circuit is connected to the second switch, the first detection terminal of the control circuit is connected to the first battery, and the second detection terminal of the control circuit is connected to the second battery.

[0007] The first switch is connected in series between the first battery and the output terminal of the power system, and the second switch is connected in series between the second battery and the output terminal of the power system;

[0008] The first equalization discharge circuit and the second equalization discharge circuit are both connected in parallel between the first battery and the second battery. The first equalization discharge circuit is used to control the first battery to discharge to the second battery with a constant discharge current, and the discharge current of the first battery is less than the charging protection current of the second battery. The second equalization discharge circuit is used to control the second battery to discharge to the first battery with a constant discharge current, and the discharge current of the second battery is less than the charging protection current of the first battery.

[0009] Optionally, the first equalization discharge circuit includes: a first detection sub-circuit, a transistor, and a discharge circuit;

[0010] The input terminal of the first detection sub-circuit is connected to the first battery and the emitter of the transistor, respectively. The output terminal of the first detection sub-circuit is connected to the base of the transistor and the first input terminal of the discharge circuit, respectively. The collector of the transistor is connected to the second input terminal of the discharge circuit, and the output terminal of the discharge circuit is connected to the second battery.

[0011] The transistor is used to control the voltage drop between the input and output terminals of the first detection sub-circuit to be constant at the conduction voltage between the base and emitter of the transistor, so that the first battery discharges to the second battery with a constant discharge current.

[0012] Optionally, the first equalization discharge circuit includes: a first detection sub-circuit, a second detection sub-circuit, and a discharge circuit;

[0013] The input terminal of the first detection sub-circuit is connected to the first battery and the first input terminal of the second detection sub-circuit, respectively, and the output terminal of the first detection sub-circuit is connected to the second input terminal of the second detection sub-circuit and the input terminal of the discharge circuit, respectively.

[0014] The driving terminal of the second detection sub-circuit is connected to the first external power supply, and the detection terminal of the second detection sub-circuit is connected to the third detection terminal of the control circuit.

[0015] The output terminal of the discharge circuit is connected to the second battery, and the control terminal of the discharge circuit is connected to the third control terminal of the control circuit.

[0016] The control circuit is used to determine the voltage drop between the input and output terminals of the first detection sub-circuit by the voltage at the detection terminal of the second detection sub-circuit, and to apply a control voltage to the discharge circuit when the voltage drop between the input and output terminals of the first detection sub-circuit is greater than or equal to the circuit voltage drop threshold, so that the first battery discharges to the second battery with a constant discharge current.

[0017] Optionally, the second detection sub-circuit includes: a power supply branch and a detection branch;

[0018] The input terminal of the power supply branch and the first input terminal of the detection branch are respectively connected to the input terminals of the first battery and the first detection sub-circuit. The output terminal of the power supply branch is connected to the power supply terminal of the detection branch, and the driving terminal of the power supply branch is connected to the first external power supply.

[0019] The second input terminal of the detection branch is connected to the output terminal of the first detection sub-circuit, and the detection terminal of the detection branch is connected to the third detection terminal of the control circuit.

[0020] The power supply branch is used to provide operating power to the detection branch, and the detection branch is used to detect the voltage drop between the input and output terminals of the first detection sub-circuit.

[0021] Optionally, the first equalization discharge circuit further includes: a protection sub-circuit;

[0022] The protection sub-circuit is connected in series between the output terminal of the discharge circuit and the second battery. The protection sub-circuit is used to prevent the current from the second battery from flowing back into the first battery when the voltage of the second battery is greater than the voltage of the first battery.

[0023] Optionally, the power system further includes: a charging circuit, a third switch, a fourth switch, and a fifth switch;

[0024] The input terminal of the charging circuit is connected to the second external power supply, the third switch is connected in series between the second external power supply and the output terminal of the power system, and the third switch is also connected to the fourth control terminal of the control circuit.

[0025] The fourth switch is connected in series between the output terminal of the charging circuit and the first battery. The fourth switch is also connected to the fifth control terminal of the control circuit. The fifth switch is connected in series between the output terminal of the charging circuit and the second battery. The fifth switch is also connected to the sixth control terminal of the control circuit.

[0026] On the other hand, a power control method is provided, applied to the control circuit of the power system, the method comprising:

[0027] Detect the voltage of the first battery and the voltage of the second battery;

[0028] When the voltage of the first battery is greater than the voltage of the second battery, and the voltage difference between the first battery and the second battery is greater than or equal to the battery voltage difference threshold, the first switch and the second switch are controlled to be disconnected so that the first battery discharges to the second battery through the first equalization discharge circuit with a constant discharge current, and the discharge current of the first battery is less than the charging protection current of the second battery.

[0029] When the voltage of the second battery is greater than the voltage of the first battery, and the voltage difference between the second battery and the first battery is greater than or equal to the battery voltage difference threshold, the first switch and the second switch are controlled to open, so that the second battery discharges to the first battery through the second equalization discharge circuit with a constant discharge current, and the discharge current of the second battery is less than the charging protection current of the first battery.

[0030] Optionally, the first equalization discharge circuit includes the first detection sub-circuit, the second detection sub-circuit, and the discharge circuit;

[0031] The step of controlling the first switch and the second switch to be disconnected so that the first battery discharges to the second battery through the first equalization discharge circuit at a constant discharge current includes:

[0032] The first switch and the second switch are controlled to open, and the voltage at the detection terminal of the second detection sub-circuit is detected;

[0033] Based on the voltage at the detection terminal of the second detection sub-circuit, the voltage drop between the input and output terminals of the first detection sub-circuit is determined;

[0034] When the voltage drop between the input and output terminals of the first detection sub-circuit is greater than or equal to the circuit voltage drop threshold, a control voltage is applied to the discharge circuit so that the first battery discharges to the second battery with a constant discharge current.

[0035] Optionally, after the control of the first switch and the second switch is disconnected, the method further includes:

[0036] Detect the voltage of the first battery and the voltage of the second battery;

[0037] When the voltage difference between the first battery and the second battery is less than the battery voltage difference threshold, the first switch and the second switch are controlled to be turned on.

[0038] On the other hand, an ultrasonic device is provided, the ultrasonic device including any of the power supply systems described above.

[0039] On the other hand, a computer-readable storage medium is provided, wherein a computer program is stored therein, and when the computer program is executed by a processor, it implements the steps of the power control method described above.

[0040] On the other hand, a computer program product containing instructions is provided that, when the instructions are executed on a computer, causes the computer to perform the steps of the power control method described above.

[0041] The technical solution provided in this application can bring at least the following beneficial effects:

[0042] This application uses a parallel equalization discharge circuit connected between the first and second batteries to ensure that the two batteries discharge in a balanced manner when connected in parallel. This ensures constant current discharge between the two batteries, and the discharge current will not exceed the charging protection current of the battery with lower piezoelectricity, thereby reducing the voltage difference between the two batteries and achieving a basic balance of the charge of the two batteries, thus protecting the dual batteries from normally supplying power to the load. Attached Figure Description

[0043] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0044] Figure 1 This is a schematic diagram of the structure of a power supply system provided in an embodiment of this application;

[0045] Figure 2 This is a schematic diagram of the structure of a first equalization discharge circuit provided in an embodiment of this application;

[0046] Figure 3 This is a schematic diagram of another first equalization discharge circuit provided in the embodiments of this application;

[0047] Figure 4 This is a schematic diagram of another power supply system provided in an embodiment of this application;

[0048] Figure 5 This is a flowchart of a power control method provided in an embodiment of this application;

[0049] Figure 6 This is a flowchart of another power control method provided in an embodiment of this application. Detailed Implementation

[0050] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the implementation methods of this application will be further described in detail below with reference to the accompanying drawings.

[0051] Please refer to Figure 1 , Figure 1 This is a schematic diagram of a power supply system provided in an embodiment of this application. The power supply system includes: a control circuit 1, a first switch 2, a second switch 3, a first battery 4, a second battery 5, a first equalizing discharge circuit 6, and a second equalizing discharge circuit 7. The first control terminal of the control circuit 1 is connected to the first switch 2, the second control terminal of the control circuit 1 is connected to the second switch 3, the first detection terminal of the control circuit 1 is connected to the first battery 4, and the second detection terminal of the control circuit 1 is connected to the second battery 5. The first switch 2 is connected in series between the first battery 4 and the output terminal of the power supply system, and the second switch 3 is connected in series between the second battery 5 and the output terminal of the power supply system. The first equalizing discharge circuit 6 and the second equalizing discharge circuit 7 are both connected in parallel between the first battery 4 and the second battery 5. The first equalizing discharge circuit 6 controls the first battery 4 to discharge to the second battery 5 with a constant discharge current, and the discharge current of the first battery 4 is less than the charging protection current of the second battery 5. The second equalizing discharge circuit 7 controls the second battery 5 to discharge to the first battery 4 with a constant discharge current, and the discharge current of the second battery 5 is less than the charging protection current of the first battery 4.

[0052] The first control terminal of control circuit 1 is connected to the first switch 2 and is used to control the opening and closing of the first switch 2; the second control terminal of control circuit 1 is connected to the second switch 3 and is used to control the opening and closing of the second switch 3. The first detection terminal of control circuit 1 is connected to the first battery 4 and is used to detect the voltage of the first battery 4; the second detection terminal of control circuit 1 is connected to the second battery 5 and is used to detect the voltage of the second battery 5.

[0053] The first switch 2 is connected in series between the first battery 4 and the output terminal of the power system to control the on / off state of the discharge path of the first battery 4. When the first switch 2 is on, the first battery 4 discharges through the output terminal of the power system to supply power to the load. When the first switch 2 is off, the first battery 4 does not supply power to the load. The second switch 3 is connected in series between the second battery 5 and the output terminal of the power system to control the on / off state of the discharge path of the second battery 5. When the second switch 3 is on, the second battery 5 discharges through the output terminal of the power system to supply power to the load. When the second switch 3 is off, the second battery 5 does not supply power to the load.

[0054] The first equalizing discharge circuit 6 and the second equalizing discharge circuit 7 are both connected in parallel between the first battery 4 and the second battery 5. The internal circuits of the first equalizing discharge circuit 6 and the second equalizing discharge circuit 7 are identical, differing only in their connection direction. The first equalizing discharge circuit 6 controls the first battery 4 to discharge to the second battery 5 with a constant discharge current, and the second equalizing discharge circuit 7 controls the second battery 5 to discharge to the first battery 4 with a constant discharge current. Furthermore, the constant discharge current from the first battery 4 to the second battery 5 and the constant discharge current from the second battery 5 to the first battery 4 may be equal or unequal; this embodiment does not limit this.

[0055] Specifically, when the first battery 4 discharges to the second battery 5, the discharge current of the first battery 4 needs to be less than the charging protection current of the second battery 5 to prevent the second battery 5 from entering a charging protection state, thereby avoiding the problem that the first battery 4 cannot continue to discharge to the second battery 5. Similarly, when the second battery 5 discharges to the first battery 4, the discharge current of the second battery 5 also needs to be less than the charging protection current of the first battery 4 to prevent the first battery 4 from entering a charging protection state, thereby avoiding the problem that the second battery 5 cannot continue to discharge to the first battery 4. In this way, it can be ensured that the two batteries discharge in a balanced manner to balance the voltage difference between the two batteries. Furthermore, the magnitudes of the charging protection currents of the first battery 4 and the second battery 5 may be equal or unequal, depending on the characteristics of the batteries themselves, and this embodiment does not limit this.

[0056] Based on the above description, the internal circuits of the first equalizing discharge circuit 6 and the second equalizing discharge circuit 7 are identical, differing only in their connection directions. That is, for the first equalizing discharge circuit 6, its input terminal is connected to the first battery 4, and its output terminal is connected to the second battery 5. For the second equalizing discharge circuit 7, its input terminal is connected to the second battery 5, and its output terminal is connected to the first battery 4. The structure of these two equalizing discharge circuits will now be described using the first equalizing discharge circuit 6 as an example.

[0057] Please refer to Figure 2 , Figure 2This is a schematic diagram of a first equalization discharge circuit provided in an embodiment of this application. The first equalization discharge circuit 6 includes: a first detection sub-circuit 61, a transistor 62, and a discharge circuit 63. The input terminal of the first detection sub-circuit 61 is connected to the first battery 4 and the emitter e of the transistor 62, respectively. The output terminal of the first detection sub-circuit 61 is connected to the base b of the transistor 62 and the first input terminal of the discharge circuit 63, respectively. The collector c of the transistor 62 is connected to the second input terminal of the discharge circuit 63, and the output terminal of the discharge circuit 63 is connected to the second battery 5. The transistor 62 is used to control the voltage drop between the input and output terminals of the first detection sub-circuit 61 to be constant at the conduction voltage between the base b and emitter e of the transistor 62, so that the first battery 4 discharges to the second battery 5 with a constant discharge current.

[0058] The first detection sub-circuit 61 is used to detect the discharge current of the first equalization discharge circuit 6. Optionally, as shown... Figure 2 As shown, the first detection sub-circuit 61 can consist of a single resistor R1, or it can consist of multiple resistors connected in series or parallel. This application embodiment does not limit the structure of the first detection sub-circuit 61 or the value of the resistor R1.

[0059] Transistors can be classified into NPN and PNP types according to their structure. In an NPN transistor, the P-type semiconductor is in the middle, with two N-type semiconductors on either side; while in a PNP transistor, the N-type semiconductor is in the middle, with two P-type semiconductors on either side. The N-type and P-type semiconductors are arranged alternately to form three regions, called the emitter, base, and collector regions. The pins leading out from these three regions are called the emitter, base, and collector, respectively. Transistor 62 is a PNP transistor, and for ease of description, it will be referred to as transistor Q2.

[0060] The discharge circuit 63 may include a MOS (Metal Oxide Semiconductor) transistor Q1 and a resistor R2. The source s of the MOS transistor Q1 is connected to the output terminal of the first detection sub-circuit 61 and the base b of the transistor Q2. The gate g of the MOS transistor Q1 is connected to one end of the resistor R2, the other end of the resistor R2 is grounded, and the drain d of the MOS transistor Q1 is connected to the second battery 5.

[0061] MOSFET Q1 can be a P-type MOSFET, and resistor R2 can be a pull-down resistor. The function of the pull-down resistor is to provide a static operating point for transistor Q2, preventing the current through the collector of transistor Q2 from increasing uncontrollably, thus ensuring that transistor Q2 always operates in the amplification region. The value of resistor R2 may vary depending on different requirements, and this embodiment does not limit this value.

[0062] When the voltage of the first battery 4 is greater than the voltage of the second battery 5, and the voltage difference between the first battery 4 and the second battery 5 is greater than or equal to the battery voltage difference threshold, the first equalization discharge circuit 6 automatically starts working. At this time, the source s of MOSFET Q1 is at a high level, and the gate g is at a low level. The voltage difference between its gate g and source s is less than the turn-on voltage, so MOSFET Q1 is turned on. Moreover, when the voltage drop across resistor R1 rises to the turn-on voltage between the base b and emitter e of transistor Q2, transistor Q2 operates in the amplification region and is in an unsaturated conduction state. Therefore, the voltage drop across resistor R1 is constant at this turn-on voltage, and the discharge current through resistor R1 is also constant, that is, the first equalization discharge circuit achieves constant current discharge.

[0063] Based on their material, transistors are generally classified into silicon transistors and germanium transistors. The base-emitter voltage of a silicon transistor is typically 0.7V, while that of a germanium transistor is typically 0.2V. This application does not limit the specific voltage across these components.

[0064] Please refer to Figure 3 , Figure 3 This is a schematic diagram of another first equalization discharge circuit provided in an embodiment of this application. The first equalization discharge circuit 6 includes: a first detection sub-circuit 61, a second detection sub-circuit 62, and a discharge circuit 63. The input terminal of the first detection sub-circuit 61 is connected to the first input terminal of the first battery 4 and the second detection sub-circuit 62, respectively. The output terminal of the first detection sub-circuit 61 is connected to the second input terminal of the second detection sub-circuit 62 and the input terminal of the discharge circuit 63, respectively. The driving terminal of the second detection sub-circuit 62 is connected to the first external power supply Vcc, and the detection terminal V_det of the second detection sub-circuit 62 is connected to the third detection terminal of the control circuit 1. The output terminal of the discharge circuit 63 is connected to the second battery 5, and the control terminal V_drv of the discharge circuit 63 is connected to the third control terminal of the control circuit 1. The control circuit 1 is used to determine the voltage drop between the input and output terminals of the first detection sub-circuit 61 by the voltage of the detection terminal V_det of the second detection sub-circuit 62, and to apply a control voltage to the discharge circuit 63 when the voltage drop between the input and output terminals of the first detection sub-circuit 61 is greater than or equal to the circuit voltage drop threshold, so that the first battery 4 discharges to the second battery 5 with a constant discharge current.

[0065] The first detection sub-circuit 61 is used to detect the discharge current of the first equalization discharge circuit. Optionally, as shown... Figure 3 As shown, the first detection sub-circuit 61 can consist of a single resistor R3, or it can consist of multiple resistors connected in series or parallel. This application embodiment does not limit the structure of the first detection sub-circuit 61 or the value of resistor R3.

[0066] The second detection sub-circuit 62 includes a power supply branch 621 and a detection branch 622. The input terminal of the power supply branch 621 and the first input terminal of the detection branch 622 are respectively connected to the first battery 4 and the input terminal of the first detection sub-circuit 61. The output terminal of the power supply branch 621 is connected to the power supply terminal of the detection branch 622, and the drive terminal of the power supply branch 621 is connected to the first external power supply Vcc. The second input terminal of the detection branch 622 is connected to the output terminal of the first detection sub-circuit 61, and the detection terminal V_det of the detection branch 622 is connected to the third detection terminal of the control circuit 1. The power supply branch 621 provides operating power to the detection branch 622, and the detection branch 622 detects the voltage drop between the input and output terminals of the first detection sub-circuit 61.

[0067] The power supply branch 621 may include a linear voltage regulator chip U1, a capacitor C1, a transistor Q3, and five resistors R4 to R8. Resistors R4 and R5 are connected in series and then in parallel between the cathode K and anode A of the linear voltage regulator chip U1. Capacitor C1 is also connected in parallel between the cathode K and anode A of the linear voltage regulator chip U1. The reference terminal R of the linear voltage regulator chip U1 is connected between resistors R4 and R5. The anode A of the linear voltage regulator chip U1 is also connected to the collector c of the transistor Q3. Resistor R6 is connected in series between the first external power supply Vcc and the base b of the transistor Q3. One end of resistor R7 is connected to the base b of the transistor Q3, and the other end is grounded. One end of resistor R8 is connected to the emitter e of the transistor Q3, and the other end is grounded.

[0068] The function of capacitor C1 is to reduce noise, and capacitor C1 can take different values ​​depending on different situations. This application does not limit this.

[0069] The linear voltage regulator chip U1 can be a TL431. Since the current through the reference terminal R of the linear voltage regulator chip U1 is very small and negligible, the current through resistors R4 and R5 can be considered equal. The voltage across the reference terminal R of the linear voltage regulator chip U1 is fixed, meaning the voltage across resistor R5 is fixed. Based on the resistance ratio of R4 and R5, the voltage across resistor R4 can be obtained, and thus the voltage across the linear voltage regulator chip U1 can be derived. For example, if the voltage across the reference terminal R of the linear voltage regulator chip U1 is 2.5V, then the voltage across resistor R5 is also 2.5V. Based on the resistance ratio of R4 and R5, the voltage across resistor R4 is 2.5V * (R4 / R5), and therefore the voltage across the linear voltage regulator chip U1 is 2.5V * (1 + R4 / R5).

[0070] The first external power supply Vcc is a low-voltage DC power supply, providing drive current to transistor Q3. Transistor Q3 can be an NPN transistor. Part of the current through resistor R6 flows through resistor R7, creating a voltage drop across R7 to provide bias voltage to transistor Q3; the other part of the current through resistor R6 enters the base b of transistor Q3. By setting the resistance values ​​of resistors R6 and R7, the current through the base b of transistor Q3 can be adjusted to ensure that transistor Q3 operates in the amplification region, in a non-saturated conduction state. The collector c of transistor Q3 is connected to the anode A of the linear voltage regulator chip U1. Thus, the current through resistors R4 and R5, as well as the bias current on the linear voltage regulator chip U1, all pass through transistor Q3, then through pull-down resistor R8, and reach the ground terminal, forming a circuit. The values ​​of resistors R4 to R8 can vary depending on the specific situation; this embodiment does not limit the specific values.

[0071] The detection branch 621 may include an operational amplifier U2, a transistor Q4, and two resistors R9 and R10. One end of resistor R9 is connected to the input terminal of the first detection sub-circuit 61 and the first battery 4, and the other end is connected to the emitter e of transistor Q4. The non-inverting input (+) of operational amplifier U2 is connected to the output terminal of the first detection sub-circuit 61, and the inverting input (-) of operational amplifier U2 is connected between resistor R9 and the emitter e of transistor Q4. The output terminal of operational amplifier U2 is connected to the base b of transistor Q4. The positive power supply terminal VS+ of operational amplifier U2 is connected to the cathode K of linear voltage regulator chip U1, and the negative power supply terminal VS- of operational amplifier U2 is connected to the anode A of linear voltage regulator chip U1. One end of resistor R10 is connected to the collector c of transistor Q4, and the other end is grounded.

[0072] The voltage at the positive power supply terminal Vs+ of operational amplifier U2 is equal to the input voltage of the first equalization discharge circuit, and the voltage at the negative power supply terminal Vs- is the input voltage minus the voltage across the linear voltage regulator chip U1. Furthermore, based on the above description, the voltage between the cathode K and anode A of the linear voltage regulator chip U1 is related to the resistance values ​​of resistors R4 and R5. Therefore, by adjusting the resistance values ​​of resistors R4 and R5, the voltages at the positive and negative power supply terminals Vs+ and Vs- of operational amplifier U2 can be adjusted. That is, power supply branch 621 provides operating power to detection branch 622. For example, by adjusting the resistance values ​​of resistors R4 and R5, the voltage between the cathode K and anode A of the linear voltage regulator chip U1 can be adjusted to 3V, meaning the voltage at the negative power supply terminal of operational amplifier U2 is 3V lower than the voltage at the positive power supply terminal.

[0073] Since the voltage at the inverting input of operational amplifier U2 is equal to the voltage at the non-inverting input, the voltage drop across resistor R3 is equal to the voltage drop across resistor R9. This voltage drop across R3 is transferred to resistor R10 through operational amplifier U2. The detection terminal V_det of detection branch 622 is connected to the third detection terminal of control circuit 1, allowing the measurement of the voltage across resistor R10. Current flows through resistor R9 to transistor Q4 and then to resistor R10, eventually reaching ground, forming a path. The base current of transistor Q4 is very small and can be ignored. The current at the inverting input of operational amplifier U2 is also negligible. Therefore, the current flowing through resistors R10 and R11 can be considered the same, with a magnitude of V_det / R10. Based on the resistance ratio of resistors R9 and R10, the voltage across resistor R9 is V_det*(R9 / R10), meaning the voltage across resistor R3 is also V_det*(R9 / R10). By setting different resistance ratios for resistors R9 and R10, different voltage drops across resistor R3 can be obtained. Thus, detection branch 622 can detect the voltage drop between the input and output terminals of the first detection sub-circuit 61. Resistors R9 and R10 can take different values ​​depending on the specific circumstances; this embodiment does not limit this.

[0074] The discharge circuit 63 may include MOSFETs Q5 and Q6 and resistor R11. The source s of MOSFET Q5 is connected to the output terminal of the first detection sub-circuit 61. Resistor R11 is connected in parallel between the source s and gate g of MOSFET Q5. The gate g of MOSFET Q5 is connected to the drain d of MOSFET Q6. The drain d of MOSFET Q5 is connected to the second battery 5. The gate g of MOSFET Q6 is connected to the third control terminal of the control circuit 1. The source s of MOSFET Q6 is grounded.

[0075] MOSFET Q5 can be a P-type MOSFET, and MOSFET Q6 can be an N-type MOSFET. When the voltage drop between the input and output terminals of the first detection sub-circuit 61 is greater than or equal to the circuit voltage drop threshold, the control circuit 1 applies a control voltage to the gate g of MOSFET Q6 through the third control terminal. After applying this control voltage, since the source s of MOSFET Q6 is at a low level and the gate g is at a high level, the voltage difference between the gate g and the source s of MOSFET Q6 is greater than its turn-on voltage, so MOSFET Q6 turns on. Current then flows through resistor R11, generating a voltage drop across resistor R11. This causes the source s of MOSFET Q5 to be at a high level and the gate g of MOSFET Q5 to be at a low level. The voltage difference between the gate g and the source s of MOSFET Q5 is less than its turn-on voltage, thus MOSFET Q5 turns on, and the first battery 4 begins to discharge to the second battery 5 with a constant discharge current.

[0076] Resistor R11 can be a discharge resistor, which discharges the voltage between the gate g and source s of MOSFET Q5. The value of resistor R11 may vary depending on different requirements, and this embodiment does not limit this value. When the voltage drop between the input and output terminals of the first detection sub-circuit 61 is less than the circuit voltage drop threshold, the control circuit 1 no longer applies a control voltage to the gate g of MOSFET Q6. At this time, both the source s and gate g of MOSFET Q6 are at a low level, and the voltage difference between the gate g and source s of MOSFET Q6 is less than its turn-on voltage, so MOSFET Q6 is turned off. However, due to the capacitive characteristics of MOSFETs, when MOSFET Q6 is turned off, the source s of MOSFET Q5 may still be at a high level, and the gate g may still be at a low level. The voltage difference between the gate g and source s of MOSFET Q5 is less than its turn-on voltage, and MOSFET Q5 remains in the on state. Therefore, by discharging through resistor R11, the voltage difference between the gate and source of MOSFET Q5 is increased to its turn-on voltage, causing MOSFET Q5 to turn off, and the first battery 4 no longer supplies power to the second battery 5.

[0077] The voltage drop threshold of the circuit can be set by adjusting the resistance ratio of resistors R9 and R10. Different values ​​can be set according to different requirements. This embodiment does not set this value.

[0078] Due to the above Figure 2 In the first equalization discharge circuit shown, constant current discharge is achieved through the turn-on voltage of transistor Q2. That is, constant current discharge can only be achieved when the voltage drop across resistor R1 is constant equal to the turn-on voltage of transistor Q2. When the voltage drop across resistor R1 is less than the turn-on voltage of transistor Q2, constant current discharge cannot be achieved. And the above... Figure 3 In the first equalization discharge circuit shown, the voltage drop across resistor R3 can be precisely set by operational amplifier U2. In this way, even if the voltage drop across resistor R3 is very small, constant current discharge can be achieved, which improves the applicability of the power supply system.

[0079] Optionally, the first equalization discharge circuit 6 further includes a protection sub-circuit 64. The protection sub-circuit 64 is connected in series between the output terminal of the discharge circuit 63 and the second battery 5. The protection sub-circuit 64 is used to prevent the current of the second battery 5 from flowing back into the first battery 4 when the voltage of the second battery 5 is greater than the voltage of the first battery 4.

[0080] Please refer to Figure 2 or Figure 3The protection sub-circuit 64 may include a diode D1, which has unidirectional conductivity. If the voltage of the second battery 5 is greater than the voltage of the first battery 4, that is, if a reverse voltage is applied to the anode and cathode of the diode D1, the diode D1 will be cut off, preventing the discharge current of the second battery 5 from flowing back into the first battery 4. Of course, the protection sub-circuit 64 may also include other electrical components, which are not limited in this embodiment.

[0081] The first equalization discharge circuit is as described above. Figure 2 In the circuit shown, diode D1 also controls the first equalization discharge circuit 6 to stop working. When the voltage of the first battery 4 is greater than the voltage of the second battery 4, and the voltage difference between the first battery 4 and the second battery 5 is less than the battery voltage difference threshold, the voltage drop across diode D1 does not reach the forward voltage of diode D1. Therefore, diode D1 is turned off, and the first battery 4 will not discharge to the second battery 5 through the first equalization discharge circuit 6.

[0082] Please refer to Figure 4 , Figure 4 This is a schematic diagram of another power system provided in an embodiment of this application. The power system further includes a charging circuit, a third switch, a fourth switch, and a fifth switch. The input terminal of the charging circuit is connected to a second external power source. The third switch is connected in series between the second external power source and the output terminal of the power system, and is also connected to the fourth control terminal of the control circuit. The fourth switch is connected in series between the output terminal of the charging circuit and the first battery, and is also connected to the fifth control terminal of the control circuit. The fifth switch is connected in series between the output terminal of the charging circuit and the second battery, and is also connected to the sixth control terminal of the control circuit.

[0083] Optionally, the charging circuit is a DC / DC (direct current to direct current) circuit that converts the input voltage into the full charge voltage of the battery to charge the first battery 4 and the second battery 5. This charging circuit can employ a BUCK (step-down) topology in this power supply system; however, the specific structure of the charging circuit is not limited in this embodiment.

[0084] The third switch is connected in series between the second external power supply and the output terminal of the power system, and is used to control the switching of the DC input voltage to the output. The third switch is also connected to the fourth control terminal of control circuit 1. Control circuit 1 controls the conduction and disconnection of the third switch by determining whether there is a DC input voltage in the power system. That is, when control circuit 1 determines that there is a DC input voltage, it controls the third switch to conduct, thereby supplying power to the load through the DC input voltage. When control circuit 1 determines that there is no DC input voltage, it controls the third switch to disconnect.

[0085] A fourth switch is connected in series between the output terminal of the charging circuit and the first battery 4 to control the on / off state of the charging path of the first battery 4. A fifth switch is connected in series between the output terminal of the charging circuit and the second battery 5 to control the on / off state of the charging path of the second battery 5. When the fourth and fifth switches are on, the charging circuit charges the first battery 4 and the second battery 5; when the fourth and fifth switches are off, the charging circuit cannot charge the first battery 4 and the second battery 5. The fourth switch is also connected to the fifth control terminal of the control circuit 1, and the fifth switch is also connected to the sixth control terminal of the control circuit 1. The control circuit 1 controls the on / off state of the fourth and fifth switches by determining whether there is a DC input voltage in the charging circuit.

[0086] In order to reduce losses, the value of the DC input voltage can be 24V, 19V or 12V, which is greater than or equal to the full charge voltage of the battery. This application embodiment does not limit this value.

[0087] In this embodiment, a balanced discharge circuit connected in parallel between the first and second batteries is used to ensure that the two batteries discharge in a balanced manner when connected in parallel. This ensures that the two batteries achieve constant current discharge and that the discharge current does not exceed the charging protection current of the battery with lower piezoelectricity, thereby reducing the voltage difference between the two batteries and achieving a basic balance of the charge of the two batteries, thus protecting the dual batteries from normally supplying power to the load.

[0088] Please refer to Figure 5 , Figure 5 This is a flowchart of a power control method provided in an embodiment of this application, which is applied to the control circuit of the aforementioned power system. Figure 5 As shown, the method includes the following steps.

[0089] Step 501: Detect the voltage of the first battery and the voltage of the second battery.

[0090] Since the first detection terminal of the control circuit is connected to the first battery and the second detection terminal of the control circuit is connected to the second battery, the first detection terminal of the control circuit can detect the voltage of the first battery and the second detection terminal of the control circuit can detect the voltage of the second battery.

[0091] The control circuit can cyclically detect the voltage of the first battery and the voltage of the second battery. Cyclic detection can also be understood as periodic detection, and the time interval between the current detection and the previous detection is very short, typically on the order of milliseconds; however, this embodiment does not limit this.

[0092] Step 502: When the voltage of the first battery is greater than the voltage of the second battery, and the voltage difference between the first battery and the second battery is greater than or equal to the battery voltage difference threshold, control the first switch and the second switch to open, so that the first battery discharges to the second battery through the first equalization discharge circuit with a constant discharge current, and the discharge current of the first battery is less than the charging protection current of the second battery.

[0093] If the voltage of the first battery is greater than the voltage of the second battery, and the voltage difference between the first and second batteries is greater than or equal to the battery voltage difference threshold, it indicates that the voltage difference between the two batteries is large. Therefore, the first battery needs to discharge to the second battery to balance the voltage difference between the two batteries.

[0094] The first equalization discharge circuit is as described above. Figure 2 In the circuit shown, the control circuit can directly control the first switch and the second switch to open, so that the first battery discharges to the second battery with a constant discharge current through the first equalization discharge circuit.

[0095] The first equalization discharge circuit is as described above. Figure 3 In the case of the circuit shown, that is, when the first equalization discharge circuit includes a first detection sub-circuit, a second detection sub-circuit, and a discharge circuit, the control circuit not only needs to control the first switch and the second switch to open, but also needs to detect the voltage at the detection terminal of the second detection sub-circuit; based on the voltage at the detection terminal of the second detection sub-circuit, the voltage drop between the input and output terminals of the first detection sub-circuit is determined; when the voltage drop between the input and output terminals of the first detection sub-circuit is greater than or equal to the circuit voltage drop threshold, a control voltage is applied to the discharge circuit so that the first battery discharges to the second battery with a constant discharge current.

[0096] First, the control circuit keeps both the first and second switches in the open state, disconnecting the discharge paths of the first and second batteries and preventing power supply to the load. Then, the control circuit detects the voltage at the detection terminal of the second detection sub-circuit. Based on this voltage, it determines the voltage drop between the input and output terminals of the first detection sub-circuit. If the calculated voltage drop between the input and output terminals of the first detection sub-circuit is greater than or equal to the circuit voltage drop threshold, the first battery needs to discharge to the second battery to balance the voltage difference. At this time, a control voltage is applied to the discharge circuit, the first equalizing discharge circuit is activated, and the first battery begins to discharge to the second battery with a constant discharge current through the first equalizing discharge circuit.

[0097] After the first and second switches are opened, the voltages of the first and second batteries can continue to be monitored. When the voltage difference between the first and second batteries is less than the battery voltage difference threshold, the first and second switches are turned on. That is, even during the discharge process from the first battery to the second battery, the voltages of both batteries can continue to be monitored. When the voltage difference between the two batteries is less than the battery voltage difference threshold, the first and second switches are turned on, thereby supplying power to the load through the first and second batteries.

[0098] However, regarding the above Figure 3 In the circuit shown, if the voltage difference between the first battery and the second battery is less than the battery voltage difference threshold, then no control voltage is applied to the discharge circuit, causing the first equalization discharge circuit to disconnect, and the first battery to stop discharging to the second battery. Then, the first switch and the second switch are controlled to turn on.

[0099] During the discharge process from the first battery to the second battery, the discharge current of the first battery needs to be less than the charging protection current of the second battery to prevent the second battery from entering the charging protection state, thereby avoiding the problem that the first battery cannot continue to discharge to the second battery to balance the voltage difference between the two batteries.

[0100] Step 503: When the voltage of the second battery is greater than the voltage of the first battery, and the voltage difference between the second battery and the first battery is greater than or equal to the battery voltage difference threshold, control the first switch and the second switch to open, so that the second battery discharges to the first battery through the second equalization discharge circuit with a constant discharge current, and the discharge current of the second battery is less than the charging protection current of the first battery.

[0101] If the voltage of the second battery is greater than that of the first battery, and the voltage difference between the second and first batteries is greater than or equal to the battery voltage difference threshold, it indicates that the voltage difference between the two batteries is large. Therefore, the second battery needs to discharge to the first battery to balance the voltage difference between the two batteries.

[0102] The second equalization discharge circuit is as described above. Figure 2 In the circuit shown, the control circuit can directly control the first switch and the second switch to open, so that the second battery discharges to the first battery with a constant discharge current through the second equalization discharge circuit.

[0103] The second equalization discharge circuit is as described above. Figure 3In the case of the circuit shown, that is, when the second equalization discharge circuit includes a first detection sub-circuit, a second detection sub-circuit, and a discharge circuit, the control circuit not only needs to control the first switch and the second switch to open, but also needs to detect the voltage at the detection terminal of the second detection sub-circuit; based on the voltage at the detection terminal of the second detection sub-circuit, the voltage drop between the input and output terminals of the first detection sub-circuit is determined; when the voltage drop between the input and output terminals of the first detection sub-circuit is greater than or equal to the circuit voltage drop threshold, a control voltage is applied to the discharge circuit so that the second battery discharges to the first battery with a constant discharge current.

[0104] First, the control circuit keeps both the first and second switches in the open state, disconnecting the discharge paths of the first and second batteries and preventing power supply to the load. Then, the control circuit detects the voltage at the detection terminal of the second detection sub-circuit. Based on this voltage, it determines the voltage drop between the input and output terminals of the first detection sub-circuit. If the calculated voltage drop between the input and output terminals of the first detection sub-circuit is greater than or equal to the circuit voltage drop threshold, the second battery needs to discharge to the first battery to balance the voltage difference. At this time, a control voltage is applied to the discharge circuit, the second equalizing discharge circuit is activated, and the second battery begins to discharge to the first battery with a constant discharge current through the second equalizing discharge circuit.

[0105] After the first and second switches are opened, the voltages of the first and second batteries can continue to be monitored. When the voltage difference between the second and first batteries is less than the battery voltage difference threshold, the first and second switches are turned on. That is, during the discharge process from the second battery to the first battery, the voltages of both batteries can continue to be monitored. When the voltage difference between the two batteries is less than the battery voltage difference threshold, the first and second switches are turned on, thereby supplying power to the load through the second and first batteries.

[0106] However, regarding the above Figure 3 In the circuit shown, if the voltage difference between the second battery and the first battery is less than the battery voltage difference threshold, then no control voltage is applied to the discharge circuit, causing the second equalization discharge circuit to disconnect, and the second battery to stop discharging into the first battery. Then, the first switch and the second switch are controlled to turn on.

[0107] During the discharge process from the second battery to the first battery, the discharge current of the second battery needs to be less than the charging protection current of the first battery to prevent the first battery from entering the charging protection state, thereby avoiding the problem that the second battery cannot continue to discharge to the first battery to balance the voltage difference between the two batteries.

[0108] Please refer to Figure 6 , Figure 6This is a flowchart of another power control method provided in an embodiment of this application. First, dual batteries are inserted into the power system. Then, the control circuit controls the first and second switches to open, disconnecting the discharge paths of the first and second batteries and preventing power supply to the load. Next, the control circuit cyclically monitors the voltages of the first and second batteries. If the difference between the voltage of the first battery and the voltage of the second battery is greater than or equal to a battery voltage difference threshold, the first equalization discharge circuit starts operating, and the first battery discharges into the second battery. If the difference between the voltage of the first battery and the voltage of the second battery is less than the battery voltage difference threshold, the first equalization discharge circuit closes, and the control circuit controls the first and second switches to open, allowing the first and second batteries to supply power to the load. Similarly, if the difference between the voltage of the second battery and the voltage of the first battery is greater than or equal to the battery voltage difference threshold, the second equalization discharge circuit starts operating, and the second battery discharges into the first battery. If the difference between the voltage of the second battery and the voltage of the first battery is less than the battery voltage difference threshold, the second equalization discharge circuit closes, and the control circuit controls the first and second switches to open, allowing both the second and first batteries to supply power to the load.

[0109] In power control methods applied to, for example Figure 1 In the power system shown, the control circuit cyclically detects the voltages of the first and second batteries and determines whether the voltage difference between the two batteries is greater than or equal to the battery voltage difference threshold. This controls the first and second batteries to discharge with a constant discharge current through either the first or second equalizing discharge circuit. The detailed process has been explained in the power control method described above and will not be repeated here. The following describes the application of the power control method to... Figure 4 The process of the power system shown will be described.

[0110] While performing the above process, the control circuit can control the conduction and disconnection of the third switch by determining whether there is a DC input voltage in the power system. That is, when the control circuit determines that there is a DC input voltage, it controls the third switch to conduct, thereby supplying power to the load through the DC input voltage. When the control circuit determines that there is no DC input voltage, it controls the third switch to disconnect. Simultaneously, the control circuit can also control the conduction and disconnection of the fourth and fifth switches by determining whether there is a DC input voltage in the charging circuit, thereby controlling the connection and disconnection of the charging paths for the first and second batteries. That is, when there is a DC input voltage in the charging circuit, it controls the fourth and fifth switches to conduct, and the charging circuit charges the first and second batteries; when there is no DC input voltage in the charging circuit, it controls the fourth and fifth switches to disconnect, and the charging circuit cannot charge the first and second batteries.

[0111] In this embodiment, a balanced discharge circuit connected in parallel between the first and second batteries is used to ensure that the two batteries discharge in a balanced manner when connected in parallel. This ensures that the two batteries achieve constant current discharge and that the discharge current does not exceed the charging protection current of the battery with lower piezoelectricity, thereby reducing the voltage difference between the two batteries and achieving a basic balance of the charge of the two batteries, thus protecting the dual batteries from normally supplying power to the load.

[0112] In some embodiments, an ultrasonic device is also provided, which includes any of the power systems described above.

[0113] In some embodiments, a computer-readable storage medium is also provided, which stores a computer program that, when executed by a processor, implements the steps of the power control method described above.

[0114] It is worth noting that the computer-readable storage medium mentioned in the embodiments of this application can be a non-volatile storage medium, in other words, it can be a non-transient storage medium.

[0115] It should be understood that all or part of the steps of the above embodiments can be implemented by software, hardware, firmware, or any combination thereof. When implemented in software, it can be implemented wholly or partially in the form of a computer program product. The computer program product includes one or more computer instructions. The computer instructions can be stored in the above-described computer-readable storage medium.

[0116] That is, in some embodiments, a computer program product containing instructions is also provided, which, when run on a computer, causes the computer to perform the steps of the power control method described above.

[0117] It should be understood that "at least one" as mentioned herein refers to one or more, and "multiple" refers to two or more. In the description of the embodiments of this application, unless otherwise stated, " / " means "or," for example, A / B can mean A or B; "and / or" in this document is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. In addition, in order to clearly describe the technical solutions of the embodiments of this application, the terms "first," "second," etc., are used in the embodiments of this application to distinguish identical or similar items with substantially the same function and effect. Those skilled in the art will understand that the terms "first," "second," etc., do not limit the quantity or execution order, and the terms "first," "second," etc., are not necessarily different.

[0118] It should be noted that the information (including but not limited to user device information, user personal information, etc.), data (including but not limited to data used for analysis, data stored, data displayed, etc.) and signals involved in the embodiments of this application are all authorized by the user or fully authorized by all parties, and the collection, use and processing of related data must comply with the relevant laws, regulations and standards of the relevant countries and regions.

[0119] The above descriptions are embodiments provided in this application and are not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A power supply system characterized by comprising: The power supply system comprises a control circuit, a first switch, a second switch, a first battery, a second battery, a first equalizing discharge circuit and a second equalizing discharge circuit; a first control end of the control circuit is connected with the first switch, a second control end of the control circuit is connected with the second switch, a first detection end of the control circuit is connected with the first battery, and a second detection end of the control circuit is connected with the second battery; the first switch is connected in series between the first battery and an output end of the power supply system, and the second switch is connected in series between the second battery and the output end of the power supply system; the first equalizing discharge circuit and the second equalizing discharge circuit are connected in parallel between the first battery and the second battery; the control circuit is configured to detect voltages of the first battery and the second battery; in a case where the voltage of the first battery is greater than the voltage of the second battery, and a voltage difference between the first battery and the second battery is greater than or equal to a battery voltage difference threshold, the first switch and the second switch are controlled to be turned off, so that the first battery discharges to the second battery through the first equalizing discharge circuit at a constant discharge current, and the discharge current of the first battery is less than a charging protection current of the second battery; in a case where the voltage of the second battery is greater than the voltage of the first battery, and the voltage difference between the second battery and the first battery is greater than or equal to the battery voltage difference threshold, the first switch and the second switch are controlled to be turned off, so that the second battery discharges to the first battery through the second equalizing discharge circuit at a constant discharge current, and the discharge current of the second battery is less than a charging protection current of the first battery.

2. The power supply system of claim 1, wherein, The first equalizing discharge circuit comprises a first detection sub-circuit, a transistor and a discharge sub-circuit. input ends of the first detection sub-circuit are connected with the first battery and an emitter of the transistor respectively, an output end of the first detection sub-circuit is connected with a base of the transistor and a first input end of the discharge sub-circuit respectively, a collector of the transistor is connected with a second input end of the discharge sub-circuit, and an output end of the discharge sub-circuit is connected with the second battery; the transistor is used for controlling a voltage drop between the input end and the output end of the first detection sub-circuit to be a conduction voltage between the base and the emitter of the transistor, so that the first battery discharges to the second battery at a constant discharge current.

3. The power supply system of claim 1, wherein, The first equalizing discharge circuit comprises a first detection sub-circuit, a second detection sub-circuit and a discharge sub-circuit. input ends of the first detection sub-circuit are connected with the first battery and a first input end of the second detection sub-circuit respectively, output ends of the first detection sub-circuit are connected with a second input end of the second detection sub-circuit and an input end of the discharge sub-circuit respectively; a driving end of the second detection sub-circuit is connected with a first external power supply, and a detection end of the second detection sub-circuit is connected with a third detection end of the control circuit; An output end of the discharging circuit is connected with the second battery, and a control end of the discharging circuit is connected with a third control end of the control circuit; The control circuit is configured to determine a voltage drop between the input end and the output end of the first detection sub-circuit through a voltage of a detection end of the second detection sub-circuit, and load a control voltage to the discharging circuit in a case where the voltage drop between the input end and the output end of the first detection sub-circuit is greater than or equal to a circuit voltage drop threshold, so as to make the first battery discharge to the second battery at a constant discharging current.

4. The power supply system of claim 3, wherein, The second detection sub-circuit comprises a power supply branch and a detection branch. An input end of the power supply branch and a first input end of the detection branch are connected with the first battery and an input end of the first detection sub-circuit respectively, an output end of the power supply branch is connected with a power supply end of the detection branch, and a driving end of the power supply branch is connected with the first external power supply. A second input end of the detection branch is connected with an output end of the first detection sub-circuit, and a detection end of the detection branch is connected with a third detection end of the control circuit. The power supply branch is configured to provide operating power for the detection branch, and the detection branch is configured to detect a voltage drop between the input end and the output end of the first detection sub-circuit.

5. The power supply system according to claim 2 or 3, wherein The first equalizing discharging circuit further comprises a protection sub-circuit. The protection sub-circuit is connected in series between the output end of the discharging circuit and the second battery, and the protection sub-circuit is configured to prevent current of the second battery from flowing back to the first battery in a case where a voltage of the second battery is greater than a voltage of the first battery.

6. The power supply system of claim 1, wherein, The power supply system further comprises a charging circuit, a third switch, a fourth switch and a fifth switch. An input end of the charging circuit is connected with a second external power supply, the third switch is connected in series between the second external power supply and an output end of the power supply system, and the third switch is further connected with a fourth control end of the control circuit. The fourth switch is connected in series between an output end of the charging circuit and the first battery, the fourth switch is further connected with a fifth control end of the control circuit, and the fifth switch is connected in series between the output end of the charging circuit and the second battery, and the fifth switch is further connected with a sixth control end of the control circuit.

7. A power supply control method characterized by comprising: The method is applied to the power supply system as claimed in any one of claims 1-5, and the method comprises: detecting a voltage of the first battery and a voltage of the second battery; in a case where the voltage of the first battery is greater than the voltage of the second battery, and a voltage difference between the first battery and the second battery is greater than or equal to a battery voltage difference threshold, controlling the first switch and the second switch to be turned off, so as to make the first battery discharge to the second battery at a constant discharging current through the first equalizing discharging circuit, and the discharging current of the first battery is less than a charging protection current of the second battery; In a case where the voltage of the second battery is greater than the voltage of the first battery, and a voltage difference between the second battery and the first battery is greater than or equal to the battery voltage difference threshold, the first switch and the second switch are controlled to be turned off, so that the second battery discharges to the first battery at a constant discharge current through the second equalization discharge circuit, and the discharge current of the second battery is less than the charge protection current of the first battery.

8. The method of claim 7, wherein, The first equalization discharge circuit comprises the first detection sub-circuit, the second detection sub-circuit, and a discharge sub-circuit. The control of the first switch and the second switch to be turned off, so that the first battery discharges to the second battery at a constant discharge current through the first equalization discharge circuit, comprises: The first switch and the second switch are controlled to be turned off, and the voltage of the detection end of the second detection sub-circuit is detected. Based on the voltage of the detection end of the second detection sub-circuit, a voltage drop between the input end and the output end of the first detection sub-circuit is determined. In a case where the voltage drop between the input end and the output end of the first detection sub-circuit is greater than or equal to a circuit voltage drop threshold, a control voltage is loaded to the discharge sub-circuit, so that the first battery discharges to the second battery at a constant discharge current.

9. The method of claim 7 or 8, wherein, After the control of the first switch and the second switch to be turned off, the method further comprises: The voltage of the first battery and the voltage of the second battery are detected. In a case where the voltage difference between the first battery and the second battery is less than the battery voltage difference threshold, the first switch and the second switch are controlled to be turned on.

10. An ultrasound apparatus, characterized by The ultrasonic device comprises the power supply system as claimed in any one of claims 1-6.

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