WO2023123729A1

WO2023123729A1 - Conversion circuit for series charging and parallel power supply

Info

Publication number: WO2023123729A1
Application number: PCT/CN2022/085896
Authority: WO
Inventors: 张立新
Original assignee: 深圳市沃特沃德信息有限公司
Priority date: 2021-12-30
Filing date: 2022-04-08
Publication date: 2023-07-06
Also published as: CN114336857B; CN114336857A

Abstract

Disclosed in the present application is a conversion circuit for series charging and parallel power supply, which conversion circuit realizes automatic switching between a series connection during charging and a parallel connection when a charger is unplugged. By means of a method for series charging and parallel power supply, the balance between two batteries during parallel discharging and series charging of the batteries can be maintained, and the problem of mutual large-current charging caused by a tiny voltage difference when the two batteries are directly connected in parallel can be solved, thereby prolonging the service life of the batteries.

Description

Conversion circuit for series charging and parallel power supply

technical field

The present application relates to a charging conversion circuit, especially a conversion circuit for series charging and parallel power supply.

Background technique

There are many fast charging protocols used in the existing charging circuits on the market, but most of them increase the output voltage of the charger to increase the charging power. In order to improve the charging efficiency of the fast charging and reduce heat generation, the switching charging IC requires The voltage difference between the input and output is as small as possible. At the same time, in order to reduce the loss of various impedances in the charging circuit, the charging current is also required not to be too large. In order to solve the above problems, two batteries are generally charged in series and connected in parallel. The method of power supply, but this method may affect the charging or discharging balance of the two batteries during the series and parallel switching process, and the battery life will be affected after a long time.

technical problem

The purpose of this application is to provide a conversion circuit for series charging and parallel power supply, aiming to solve the problem of unstable charging or discharging balance of the two batteries in the dual battery charging circuit in the prior art, which leads to the problem of affecting the life of the battery.

technical solution

A conversion circuit for series charging and parallel power supply, including a conversion module and a step-down module;

The battery charging input terminal of the conversion module is used to connect with the battery power supply terminal of the external power supply, the voltage detection input terminal of the conversion module is used to be connected with the power supply terminal of the external power supply, and the output terminal of the conversion module is used for It is connected to the input end of the step-down module, the output end of the step-down module is connected to an external load, the conversion module is used to automatically switch the series and parallel states of the battery, and the step-down module is used to switch the conversion module The output voltage is regulated and passed through to the load after output;

Wherein, the conversion module includes a first switching unit, a second switching unit, a third switching unit, a fourth switching unit, a first MOS transistor, a second MOS transistor, a first battery, and a second battery;

The voltage detection input terminal of the conversion module is used to connect with the control terminal of the third switching unit, the first terminal of the third switching unit is grounded, and the second terminal of the third switching unit is used for connecting with the control terminal of the third switching unit. The gate of the first MOS transistor is connected, one end of the second switching unit is used for connecting with the input end of the step-down module, and the drain of the first MOS transistor is used for connecting with the drain of the second MOS transistor pole and the negative pole of the second battery, the source of the first MOS transistor is grounded, the gate of the second MOS transistor is used to connect with the second terminal of the fourth switching unit, and the fourth switching unit The control terminal of the control terminal is used to connect with the voltage detection input terminal of the conversion module, the first terminal of the fourth switching unit is grounded, and the source of the second MOS transistor is used for connecting with one terminal of the second switching unit and The positive pole of the first battery is connected, the negative pole of the first battery is grounded, the positive pole of the second battery is used to connect with the battery power supply end of the external power supply and one end of the first switching unit, and the first battery The other end of a switching unit is used to connect with the input end of the step-down module and the other end of the second switching unit, the first switching unit, the second switching unit, the third switching unit and The fourth switching unit is used for switching between two states of unidirectional on or off according to the obtained electric signal.

Beneficial effect

Through the above-mentioned structure, when the output voltages of the first battery and the second battery are inconsistent, the first switching unit and the second switching unit cut off the output of the battery with the lower output voltage, and cut off the output of the battery with the higher output voltage. When the output falls back to the output voltage of the battery with the lower output voltage, it will be turned on again, so as to finally ensure that the charging voltage and output voltage of the first battery are consistent with the second battery, and realize the promotion of dual-battery charging circuit. The effect of charge or discharge balance of two batteries.

Description of drawings

FIG. 1 is a schematic structural diagram of a conversion circuit for series charging and parallel power supply according to an embodiment;

Fig. 2 is a schematic circuit diagram of a conversion module of an embodiment;

3 is a schematic circuit diagram of a conversion module of another embodiment;

4 is a schematic circuit diagram of a first switching unit of an embodiment;

5 is a schematic circuit diagram of a second switching unit of an embodiment;

The names of the symbols in the figure are: 1-conversion module, 2-decompression module, 3-first switching unit, 4-second switching unit, 5-third switching unit, 6-fourth switching unit.

BEST MODE FOR CARRYING OUT THE INVENTION

It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

Those skilled in the art will understand that unless otherwise stated, the singular forms "a", "an", "said" and "the" used herein may also include plural forms. It should be further understood that the word "comprising" used in the description of the present invention refers to the presence of said features, integers, steps, operations, elements and/or components, but does not exclude the presence or addition of one or more other features, Integers, steps, operations, elements, components, and/or groups thereof. The expression "and/or" used herein includes all or any elements and all combinations of one or more associated listed items.

Referring to FIG. 1, the present application provides a conversion circuit for series charging and parallel power supply, including a conversion module 1 and a step-down module 2;

The battery charging input terminal of the conversion module 1 is used to connect to the battery power supply terminal of the external power supply, the voltage detection input terminal of the conversion module 1 is used to be connected to the power supply terminal of the external power supply, and the output terminal of the conversion module 1 is used to connect with the step-down The input terminal of module 2 is connected, the output terminal of step-down module 2 is connected to an external load, conversion module 1 is used to automatically switch between series charging and parallel power supply, and step-down module 2 is used to stabilize the output voltage of conversion module 1 and pass it through output to load;

Referring to FIG. 2, the conversion module 1 includes a first switching unit 3, a second switching unit 4, a third switching unit 5, a fourth switching unit 6, a first MOS transistor Q1, a second MOS transistor Q2, a first battery B1 and a second battery B2;

The voltage detection input terminal of the conversion module 1 is used to connect with the control terminal of the third switching unit 5, the first terminal of the third switching unit 5 is grounded, and the second terminal of the third switching unit 5 is used for connecting with the control terminal of the first MOS transistor Q1. The gate is connected, one end of the second switching unit 4 is used to connect to the input end of the step-down module 2, and the drain of the first MOS transistor Q1 is used to be connected to the drain of the second MOS transistor Q2 and the negative electrode of the second battery B2 , the source of the first MOS transistor Q1 is grounded, the gate of the second MOS transistor Q2 is used to connect to the second terminal of the fourth switching unit 6 , and the control terminal of the fourth switching unit 6 is used for voltage detection with the conversion module 1 The input ends are connected, the first end of the fourth switching unit 6 is grounded, the source of the second MOS transistor Q2 is used to connect with one end of the second switching unit 4 and the positive pole of the first battery B1, and the negative pole of the first battery B1 is grounded. The positive pole of the second battery B2 is used to connect with the battery power supply end of the external power supply and one end of the first switching unit 3, and the other end of the first switching unit 3 is used for connecting with the input end of the step-down module 2 and the second switching unit The other end of 4 is connected, and the first switching unit 3 , the second switching unit 4 , the third switching unit 5 and the fourth switching unit 6 are used to switch the two states of on or off according to the obtained electrical signal.

As described in the above embodiment, the conversion module 1 automatically switches the states of the first battery B1 and the second battery B2 from series charging to parallel power supply, and since the conversion module 1 can output series output voltage or parallel output voltage, the two The difference between the output values of these two voltages will be doubled, so it is necessary to connect the step-down module 2 to step down and stabilize the voltage. The voltages at the terminals are the same; and because the highest output voltage is set in the step-down module 2, when the conversion module 1 loses the external power supply, the first battery B1 and the second battery B2 form a parallel power supply and output the voltage to the step-down module 2. At this time, the power supply obtained by the step-down module 2 is lower than the maximum output voltage, then the step-down module 2 loses the voltage regulation function and becomes the input and output direct-through state, and the output voltage follows the voltage changes of the first battery B1 and the second battery B2 And change.

In addition, when the battery positive terminal and the voltage detection input terminal of the conversion module 1 are not powered, the control terminals of the third switching unit 5 and the fourth switching unit 6 and the gate of the second MOS transistor Q2 do not obtain electrical signals, and the first The gate of the MOS transistor Q1 obtains the electrical signal input from the first battery B1, and the first MOS transistor Q1 is turned on. At this time, the negative poles of the first battery B1 and the second battery B2 are connected together, and the positive pole of the second battery B2 is connected. The voltage is output to the first switching unit 3, and the positive pole of the first battery B1 outputs the voltage to the second switching unit 4. At this time, the first switching unit 3 and the second switching unit 4 conduct unidirectionally, thereby forming a battery through the first battery B1 and the second switching unit 4. The second battery B2 performs the function of parallel power supply.

In addition, when the output voltages of the first battery B1 and the second battery B2 are inconsistent, the switching unit on the side with the lower voltage is switched to the cut-off state because the voltage at the output terminal is larger than the voltage at the input terminal, so that the voltage is higher by one The battery on the side will give priority to power supply until the output voltages of the first battery B1 and the second battery B2 are consistent, and then the switching unit on the side with a lower voltage will be switched to the on state again, so as to ensure that the first battery B1 and the second battery B2 are kept in the same state. The voltage of the second battery B2 is always equal during use;

And when the battery charging terminal and the voltage detection input terminal of the conversion module 1 have power supply, the voltage of the battery charging terminal and the voltage detection input terminal of the conversion module 1 rises, and at this time the third switching unit 5 and the fourth switching unit 6 are successively turned on , then the first MOS transistor Q1 is turned off at this time, and then the second MOS transistor Q2 is turned on, so that the negative electrode of the second battery B2 is connected to the positive electrode of the first battery B1, forming a series structure. At this time, the positive electrode of the second battery B2 is connected to the battery charging terminal of the conversion module 1, and starts charging in series, and stops charging after being fully charged. At this time, the state that the first MOS transistor Q1 is turned off and the second MOS transistor Q2 is turned on is maintained. When the charger is unplugged, that is, the voltage at the voltage detection input terminal of the conversion module 1 drops rapidly, the fourth switching unit 6 will be turned off before the first MOS transistor Q1, so that the second MOS transistor Q2 is disconnected first and then the second MOS transistor Q2 is turned off. The first MOS transistor Q1 is turned on to prevent the two ends of the first battery B1 from being short-circuited during the state switching process between the first MOS transistor Q1 and the second MOS transistor Q2.

This application adopts the above structure, when the output voltages of the first battery B1 and the second battery B2 are inconsistent, the first switching unit 3 and the second switching unit 4 cut off the output of the battery with the lower output voltage, and when the output voltage is lower When the output voltage of the higher battery falls back to the same as the output voltage of the battery with the lower output voltage, it will be turned on again, so as to ensure that the voltage of the first battery B1 is consistent with the voltage of the second battery B2, and realize the dual-battery charging circuit. The effect of the charge or discharge balance of the two batteries.

Referring to Fig. 2, in one embodiment, the conversion circuit for series charging and parallel power supply further includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5 and a sixth resistor R6;

One end of the second resistor R2 and one end of the sixth resistor R6 are used to connect to the voltage detection input end of the conversion module 1, and the other end of the second resistor R2 is used to control one end of the first resistor R1 and the third switching unit 5 The other end of the first resistor R1 is connected to the ground, one end of the third resistor R3 is used to connect the second end of the third switching unit 5 and the gate of the first MOS transistor Q1, and the other end of the third resistor R3 is used for Connected to the input end of the step-down module 2, one end of the fourth resistor R4 is used to connect to the gate of the second MOS transistor Q2 and the second end of the fourth switching unit 6, and the other end of the sixth resistor R6 is used to connect to the second end of the fourth resistor R6 The control end of the four switching unit 6 is connected to one end of the fifth resistor R5, the other end of the fifth resistor R5 is grounded, and the other end of the fourth resistor R4 is used to connect with the source of the second MOS transistor Q2 and the second switching unit 4. The first terminal is connected to the positive terminal of the first battery B1.

As described in the above embodiment, the first resistor R1 is used to provide a pull-up signal to the third switching unit 5, the third resistor R3 is used to provide a pull-up signal to the first MOS transistor Q1, and the fourth resistor R4 is used to provide a pull-up signal to the second MOS transistor Q1. The MOS transistor Q2 provides a pull-up signal, the fifth resistor R5 is used to provide a pull-down signal to the fourth switching unit 6, the second resistor R2 and the sixth resistor R6 are used to divide the voltage input from the voltage detection input terminal of the conversion module 1 .

Referring to FIG. 1 , in one embodiment, the step-down module 2 is a BUCK step-down circuit.

As described in the above embodiments, the function of the BUCK step-down circuit is to make the output voltage when the batteries are connected in series or in parallel meet the voltage range required by the load with as little loss as possible.

Referring to FIG. 4, in one embodiment, the first switching unit 3 is also used to connect the positive pole and the negative pole of the second battery B2. The first switching unit 3 includes a first low-power comparator U1, a third MOS transistor Q3, a first a pull-up resistor R7, a first voltage dividing resistor R9, a second voltage dividing resistor R10, a third voltage dividing resistor R11 and a fourth voltage dividing resistor R12;

The drain of the third MOS transistor Q3 is used to connect with the third voltage dividing resistor R11 and the battery power supply end of the external power supply, and the gate of the third MOS transistor Q3 is used to connect with one end of the first pull-up resistor R7 and the first The output terminal of the low-power comparator U1 (OD structure, that is, OPEN DRAIN is open-drain. If the output of the comparator is a PUSH-PULL structure, it is necessary to add a MOS tube at the output end to change to an OD structure. U2 is connected with (the same below), and the positive power supply end of the first low-power comparator U1 is used to connect with The positive pole of the second battery B2 is connected, the negative power supply terminal of the first low-power comparator U1 is used to connect with the negative pole of the second battery B2, and the inverting input terminal of the first low-power comparator U1 is used to communicate with the third branch The other end of the piezoresistor R11 is connected to one end of the fourth voltage dividing resistor R12, and the non-inverting input end of the first low-power comparator U1 is used to connect to one end of the first voltage dividing resistor R9 and one end of the second voltage dividing resistor R10 (Note: If the output logic of the comparator is reversed, the connection between the non-inverting terminal and the inverting terminal needs to be reversed), the other end of the second voltage dividing resistor R10 and the other end of the fourth voltage dividing resistor R12 are grounded, the first dividing The other end of the piezoresistor R9 is used to connect with the source of the third MOS transistor Q3 , the other end of the first pull-up resistor R7 and the input end of the step-down module 2 .

As described in the above embodiment, the third MOS transistor Q3 is a PMOS type MOS transistor. When the second battery B2 is used to match the output voltage of the first battery B1, the drain of the third MOS transistor Q3 obtains the output voltage of the second battery B2. At this time, the drain voltage of the third MOS transistor Q3 is higher than the source voltage, and at the same time, the voltage obtained by the inverting input terminal of the first low-power comparator U1 is greater than the non-inverting input of the first low-power comparator U1 At this time, the internal MOS transistor of U1 is turned on, and the output (OD structure) of the first low-power comparator U1 is pulled down, then the first low-power comparator U1 outputs a low level at this time At this time, the gate of the third MOS transistor Q3 obtains the low-level signal output by the first low-power comparator U1, and the third MOS transistor Q3 is turned on at this time, thereby realizing the source of the third MOS transistor Q3 and the conduction function between the drains;

And when the output voltage of the second battery B2 is inconsistent with the output voltage of the first battery B1, such as B1 is higher than B2, the drain voltage of the third MOS transistor Q3 is lower than the source voltage at this time, then the first low-power comparator U1 The output voltage is pulled up to a high level by the first pull-up resistor R7. At this time, the gate of the third MOS transistor Q3 obtains the high-level signal output by the first low-power comparator U1. At this time, the third MOS transistor Q3 cut off, thereby realizing the reverse cut-off function between the source and the drain of the third MOS transistor Q3.

Referring to FIG. 5 , in one embodiment, the second switching unit 4 is also used to connect the positive pole and the negative pole of the first battery B1. The second switching unit 4 includes a second low-power comparator U2, a fourth MOS transistor Q4, a second Two pull-up resistors R8, fifth voltage dividing resistor R13, sixth voltage dividing resistor R14, seventh voltage dividing resistor R15 and eighth voltage dividing resistor R16;

The drain of the fourth MOS transistor Q4 is used to connect with the source of the second MOS transistor Q2, and the gate of the fourth MOS transistor Q4 is used to connect with one end of the second pull-up resistor R8 and the second low-power comparator U2. The output (drain) is connected, the positive power supply terminal of the second low power consumption comparator U2 is used to connect with the positive pole of the first battery B1, and the negative power supply terminal of the second low power consumption comparator U2 is used to connect with the positive pole of the first battery B1 The negative pole is connected to the ground, the inverting input terminal of the second low-power comparator U2 is used to connect with the other end of the seventh voltage dividing resistor R15 and one end of the eighth voltage dividing resistor R16, and the second low-power comparator U2 The non-inverting input terminal is used to connect with one end of the fifth voltage dividing resistor R13 and one end of the sixth voltage dividing resistor R14, the other end of the sixth voltage dividing resistor R14 and the other end of the eighth voltage dividing resistor R16 are grounded, and the fifth voltage dividing resistor The other end of the resistor R13 is used to connect to the source of the fourth MOS transistor Q4, the other end of the second pull-up resistor R8 and the input end of the step-down module 2;

As described in the above embodiment, the fourth MOS transistor Q4 is a PMOS type MOS transistor. When the second battery B2 is used to match the output voltage of the first battery B1, the drain of the fourth MOS transistor Q4 obtains the output voltage of the first battery B1. At this time, the drain voltage of the fourth MOS transistor Q4 is higher than the source voltage, and at the same time, the voltage at the inverting input terminal of the second low-power comparator U2 is higher than the voltage at the non-inverting input terminal. At this time, the internal The MOS transistor is turned on, and the output (drain) voltage of the second low-power comparator U2 is pulled down. At this time, the second low-power comparator U2 outputs a low-level signal. At this time, the gate of the fourth MOS transistor Q4 Obtaining the low-level signal output by the second low-power comparator U2, the fourth MOS transistor Q4 is turned on at this time, thereby realizing the forward conduction function between the source and the drain of the fourth MOS transistor Q4;

And when the output voltage of the second battery B2 is inconsistent with the output voltage of the first battery B1, such as B2 is higher than B1, the drain voltage of the fourth MOS transistor Q4 is lower than the source voltage at this time, then the second low power consumption comparator U2 The drain output voltage is pulled up to a high level by the second pull-up resistor R8. At this time, the gate of the fourth MOS transistor Q4 obtains a high-level signal output by the second low-power comparator U2. At this time, the fourth MOS The transistor Q4 is turned off, thereby realizing the reverse cutoff function between the source and the drain of the fourth MOS transistor Q4.

Referring to FIG. 3 , in one embodiment, the third switching unit 5 is a first triode Q5;

The base of the first triode Q5 is the control terminal of the third switching unit 5, the collector of the first triode Q5 is the second terminal of the third switching unit 5, and the emitter of the first triode Q5 is the third switching unit. the first end of unit 5;

As described in the above embodiment, the base of the first triode Q5 is used to connect with the other end of the second resistor R2 and one end of the first resistor R1, the emitter of the first triode Q5 is grounded, and the first triode Q5 The collector of the transistor Q5 is used to connect with one end of the third resistor R3 and the gate of the first MOS transistor Q1. When the base of the first transistor Q5 obtains a high-level signal, the first transistor Q5 switches is in the conduction state, thereby connecting the emitter of the first transistor Q5 and the collector of the first transistor Q5.

Referring to FIG. 3 , in one embodiment, the fourth switching unit 6 is a second transistor Q6;

The base of the second triode Q6 is the control terminal of the fourth switching unit 6, the collector of the second triode Q6 is the second end of the fourth switching unit 6, and the emitter of the second triode Q6 is the fourth switching unit. The first end of unit 6.

As described in the above embodiment, the base of the second triode Q6 is used to connect with the other end of the sixth resistor R6 and one end of the fifth resistor R5, the emitter of the second triode Q6 is grounded, and the second triode Q6 The collector of the transistor Q6 is used to connect with the gate of the second MOS transistor Q2 and one end of the fourth resistor R4. When the base of the second transistor Q6 receives a high level signal, the second transistor Q6 switches is in the conduction state, thereby connecting the emitter of the second transistor Q6 and the collector of the second transistor Q6.

Referring to FIG. 2, in one embodiment, the third switching unit 5 is a fifth MOS transistor Q7;

The gate of the fifth MOS transistor Q7 is the control terminal of the third switching unit 5, the drain of the fifth MOS transistor Q7 is the second terminal of the third switching unit 5, and the source of the fifth MOS transistor Q7 is the first terminal of the third switching unit 5. one end.

As described in the above embodiment, the gate of the fifth MOS transistor Q7 is used to connect with the other end of the second resistor R2 and one end of the first resistor R1, the source of the fifth MOS transistor Q7 is grounded, and the fifth MOS transistor Q7 The drain is used to connect with one end of the third resistor R3 and the gate of the first MOS transistor Q1, and when the gate of the fifth MOS transistor Q7 obtains a high-level signal, the fifth MOS transistor Q7 is switched to a conduction state, Thus, the gate of the fifth MOS transistor Q7 and the drain of the fifth MOS transistor Q7 are turned on.

Referring to FIG. 2, in one embodiment, the fourth switching unit 6 is a sixth MOS transistor Q8;

The gate of the sixth MOS transistor Q8 is the control terminal of the fourth switching unit 6, the drain of the sixth MOS transistor Q8 is the second terminal of the fourth switching unit 6, and the source of the sixth MOS transistor Q8 is the first terminal of the fourth switching unit 6. one end.

As described in the above embodiment, the gate of the sixth MOS transistor Q8 is used to connect with the other end of the sixth resistor R6 and one end of the fifth resistor R5, the source of the sixth MOS transistor Q8 is grounded, and the The drain is used to connect to the gate of the second MOS transistor Q2 and one end of the fourth resistor R4. When the gate of the sixth MOS transistor Q8 obtains a high-level signal, the sixth MOS transistor Q8 switches to a conduction state. Thus, the drain of the sixth MOS transistor Q8 and the source of the sixth MOS transistor Q8 are turned on.

In one embodiment, the set output voltage of the step-down module 2 is 4.2V, and the working voltage range of the step-down module 2 is 2.8V-9V.

As described in the above embodiment, the step-down module 2 presets to output a voltage of 4.2 volts. At the same time, since the first battery B1 and the second battery B2 in the conversion module 1 may output in parallel or in series, the step-down module The operating voltage range of 2 must cover the parallel output voltage of the first battery B1 and the second battery B2 and the series output voltage of the first battery B1 and the second battery B2, so the rated operating voltage range of the step-down module 2 is 2.8V～9V .

In one embodiment, the voltage dividing ratio between the first voltage dividing resistor R9 and the second voltage dividing resistor R10 and the third voltage dividing resistor R11 and the fourth voltage dividing resistor R12 is at least 1:2 and at most 1:2 3. The fifth voltage dividing resistor R13 and the sixth voltage dividing resistor R14 are used for the voltage dividing ratio between the seventh voltage dividing resistor R15 and the eighth voltage dividing resistor R16 with a minimum of 1:2 and a maximum of 1:3.

As described in the above embodiment, the first voltage dividing resistor R9 and the second voltage dividing resistor R10 are used to divide the voltage ratio of the third voltage dividing resistor R11 and the fourth voltage dividing resistor R12 so that the first low power consumption comparator U1 The input voltage of the first low-power comparator U1 is limited to an appropriate range, thereby preventing the sensitivity of the first low-power comparator U1 from decreasing due to the input voltage of the first low-power comparator U1 being too high or too low;

The fifth voltage-dividing resistor R13 and the sixth voltage-dividing resistor R14 are used for the voltage-dividing ratio of the seventh voltage-dividing resistor R15 and the eighth voltage-dividing resistor R16 to limit the input voltage of the second low-power comparator U2 to a suitable Range, so as to prevent the input voltage of the second low-power comparator U2 from being too high or too low, causing the sensitivity of the second low-power comparator U2 to decrease.

In one embodiment, the resistance values of the first pull-up resistor R7 and the second pull-up resistor R8 are greater than or equal to 1 MΩ.

As described in the above embodiment, in order to reduce the standby power consumption of the first switching unit 3 and the second switching unit 4, the resistance values of the first pull-up resistor R7 and the second pull-up resistor R8 are set to be greater than or equal to 1 MΩ, thereby realizing The standby power consumption of the first switching unit 3 and the second switching unit 4 can be reduced while realizing the function of a normal pull-up resistor.

In one embodiment, the first battery B1 and the second battery B2 are lithium-ion rechargeable batteries, and the output voltage is 3.0V-4.3V.

In one embodiment, the first switching unit 3 is a first equivalent diode D1.

In one embodiment, the second switching unit 4 is a second equivalent diode D2.

The anode of the first equivalent diode D1 is the first end of the first switching unit 3, the cathode of the first equivalent diode D1 is the second end of the first switching unit 3, and the anode of the second equivalent diode D2 is the second end of the switching unit 3. The first end of the unit 4, the cathode of the second equivalent diode D2 is the second end of the second switching unit 4;

As described in the above-mentioned embodiments, the first equivalent diode D1 and the second equivalent diode D2 are used to conduct when the positive pole obtains a voltage higher than the negative pole, and when the negative pole obtains a higher voltage than the positive pole, the first equivalent diode D2 The diode D1 and the second equivalent diode D2 are switched to a cut-off state, so as to realize the function of forward conduction and reverse cut-off.

Based on the above-mentioned embodiments, it can be seen that the greatest beneficial effect of the present application lies in: when the output voltages of the first battery B1 and the second battery B2 are inconsistent, the first switching unit 3 and the second switching unit 4 will output the output voltage of the battery with the lower voltage. Cut off, and re-conduct when the output of the battery with the higher output voltage falls back to the output voltage of the battery with the lower output voltage, so as to finally ensure the voltage of the first battery B1 and the second battery B2 Consistent, the effect of improving the charging or discharging balance of the two batteries in the double-battery charging circuit is realized, and the unidirectional conduction of the equivalent diode is replaced by a low-resistance MOS tube circuit, which greatly reduces the loss.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the description of the present invention and the contents of the accompanying drawings, or directly or indirectly used in other related All technical fields are equally included in the scope of patent protection of the present invention.

Claims

A conversion circuit for series charging and parallel power supply, characterized in that it includes a conversion module and a step-down module;

The battery charging input terminal of the conversion module is used to connect with the battery power supply terminal of the external power supply, the voltage detection input terminal of the conversion module is used to be connected with the power supply terminal of the external power supply, and the output terminal of the conversion module is used for It is connected to the input end of the step-down module, the output end of the step-down module is connected to an external load, the conversion module is used to automatically switch the series and parallel states of the battery, and the step-down module is used to switch the conversion module The output voltage is regulated and passed through to the load after output;

Wherein, the conversion module includes a first switching unit, a second switching unit, a third switching unit, a fourth switching unit, a first MOS transistor, a second MOS transistor, a first battery, and a second battery;

The voltage detection input terminal of the conversion module is used to connect with the control terminal of the third switching unit, the first terminal of the third switching unit is grounded, and the second terminal of the third switching unit is used for connecting with the control terminal of the third switching unit. The gate of the first MOS transistor is connected, one end of the second switching unit is used for connecting with the input end of the step-down module, and the drain of the first MOS transistor is used for connecting with the drain of the second MOS transistor pole and the negative pole of the second battery, the source of the first MOS transistor is grounded, the gate of the second MOS transistor is used to connect with the second terminal of the fourth switching unit, and the fourth switching unit The control terminal of the control terminal is used to connect with the voltage detection input terminal of the conversion module, the first terminal of the fourth switching unit is grounded, and the source of the second MOS transistor is used for connecting with one terminal of the second switching unit and The positive pole of the first battery is connected, the negative pole of the first battery is grounded, the positive pole of the second battery is used to connect with the battery power supply end of the external power supply and one end of the first switching unit, and the first battery The other end of a switching unit is used to connect with the input end of the step-down module and the other end of the second switching unit, the first switching unit, the second switching unit, the third switching unit and The fourth switching unit is used to switch between the on and off states according to the obtained electrical signal.
The conversion circuit for series charging and parallel power supply according to claim 1, further comprising a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor and a sixth resistor;

One end of the second resistor and one end of the sixth resistor are used to be connected to the voltage detection input end of the conversion module, and the other end of the second resistor is used to be connected to one end of the first resistor and the The control end of the third switching unit is connected, the other end of the first resistor is grounded, and one end of the third resistor is used to be connected to the second end of the third switching unit and the gate of the first MOS transistor. , the other end of the third resistor is used to connect to the input end of the step-down module, and one end of the fourth resistor is used to connect to the gate of the second MOS transistor and the first end of the fourth switching unit The other end of the sixth resistor is connected to the control end of the fourth switching unit and one end of the fifth resistor, the other end of the fifth resistor is grounded, and the other end of the fourth resistor is connected to the ground. The other end is used to connect with the source of the second MOS transistor, the first end of the second switching unit and the positive electrode of the first battery.
The conversion circuit for series charging and parallel power supply according to claim 1, wherein the first switching unit is also used to connect with the positive pole and the negative pole of the second battery, and the first switching unit includes a first low A power consumption comparator, a third MOS transistor, a first pull-up resistor, a first voltage dividing resistor, a second voltage dividing resistor, a third voltage dividing resistor and a fourth voltage dividing resistor;

The drain of the third MOS transistor is used to connect to the third voltage dividing resistor and the battery power supply end of the external power supply, and the gate of the third MOS transistor is used to connect to the first pull-up resistor One terminal is connected to the output terminal of the first low-power comparator, the positive power supply terminal of the first low-power comparator is used to connect with the positive pole of the second battery, and the first low-power comparator The negative power supply terminal of the first low power comparator is used for connecting with the negative terminal of the second battery, and the inverting input terminal of the first low power comparator is used for connecting with the other end of the third voltage dividing resistor and the fourth voltage dividing resistor. One end of the resistor is connected, and the non-inverting input end of the first low-power comparator is used to connect with one end of the first voltage dividing resistor and one end of the second voltage dividing resistor, and the second voltage dividing resistor The other end and the other end of the fourth voltage dividing resistor are grounded, and the other end of the first voltage dividing resistor is used to connect with the source of the third MOS transistor, the other end of the first pull-up resistor and the The input terminal of the step-down module is connected.
The conversion circuit for series charging and parallel power supply according to claim 3, characterized in that, the second switching unit is also used to connect with the positive pole and the negative pole of the first battery, and the second switching unit includes a second low Power consumption comparator, fourth MOS transistor, second pull-up resistor, fifth voltage dividing resistor, sixth voltage dividing resistor, seventh voltage dividing resistor and eighth voltage dividing resistor;

The drain of the fourth MOS transistor is used to connect to the source of the second MOS transistor, and the gate of the fourth MOS transistor is used to connect to one end of the second pull-up resistor and the second low voltage transistor. The drain of the power consumption comparator is connected, the positive power supply terminal of the second low power consumption comparator is used for connecting with the positive pole of the first battery, and the negative power supply terminal of the second low power consumption comparator is used for connecting with the positive pole of the first battery. The negative pole of the first battery is connected, the inverting input terminal of the second low-power comparator is used to connect with the other end of the seventh voltage dividing resistor and one end of the eighth voltage dividing resistor, and the The non-inverting input terminal of the second low power consumption comparator is used to connect with one end of the fifth voltage dividing resistor and one end of the sixth voltage dividing resistor, and the other end of the sixth voltage dividing resistor and the eighth voltage dividing resistor The other end of the voltage dividing resistor is grounded, and the other end of the fifth voltage dividing resistor is used to connect with the source of the fourth MOS transistor, the other end of the second pull-up resistor and the input terminal of the step-down module connected.
The conversion circuit for series charging and parallel power supply according to claim 1, wherein the third switching unit is a first triode;

The base of the first triode is the control terminal of the third switching unit, the collector of the first triode is the second terminal of the third switching unit, and the first triode The emitter is a first end of the third switching unit.
The conversion circuit for series charging and parallel power supply according to claim 1, wherein the fourth switching unit is a second triode;

The base of the second triode is the control terminal of the fourth switching unit, the collector of the second triode is the second end of the fourth switching unit, and the second triode The emitter is a first end of the fourth switching unit.
The conversion circuit for series charging and parallel power supply according to claim 1, wherein the third switching unit is a fifth MOS transistor;

The gate of the fifth MOS transistor is the control terminal of the third switching unit, the drain of the fifth MOS transistor is the second end of the third switching unit, and the source of the fifth MOS transistor is the the first end of the third switching unit.
The conversion circuit for series charging and parallel power supply according to claim 1, wherein the fourth switching unit is a sixth MOS transistor;

The gate of the sixth MOS transistor is the control terminal of the fourth switching unit, the drain of the sixth MOS transistor is the second end of the fourth switching unit, and the source of the sixth MOS transistor is the The first end of the fourth switching unit.
The conversion circuit for series charging and parallel power supply according to claim 4, wherein the first voltage dividing resistor and the second voltage dividing resistor are used to cooperate with the third voltage dividing resistor and the fourth voltage dividing resistor. The voltage dividing ratio between the piezoresistors is at least 1:2, and the maximum is 1:3. The fifth voltage dividing resistor and the sixth voltage dividing resistor are used to cooperate with the seventh voltage dividing resistor and the eighth voltage dividing resistor. The minimum voltage division ratio between the voltage division resistors is 1:2, and the maximum is 1:3.
The conversion circuit for series charging and parallel power supply as claimed in claim 4, wherein the resistance values of the first pull-up resistor and the second pull-up resistor are greater than or equal to 1 MΩ.
The conversion circuit for series charging and parallel power supply according to claim 1, wherein the step-down module is a BUCK step-down circuit.
The conversion circuit for series charging and parallel power supply according to claim 1, wherein the set output voltage of the step-down module is 4.2V, and the working voltage range of the step-down module 2 is 2.8V-9V.
The conversion circuit for series charging and parallel power supply according to claim 1, wherein the first battery and the second battery are lithium-ion rechargeable batteries, and the output voltage of the first battery and the second battery is 3.0 V-4.3V.
The conversion circuit for series charging and parallel power supply according to claim 1, wherein the first switching unit is a first equivalent diode.
The conversion circuit for series charging and parallel power supply according to claim 1, wherein the second switching unit is a second equivalent diode.