CN220122649U

CN220122649U - Automatic switching control circuit, electric tool and electric tool system

Info

Publication number: CN220122649U
Application number: CN202321231600.XU
Authority: CN
Inventors: 韦泽锋; 李标
Original assignee: Globe Jiangsu Co Ltd
Current assignee: Globe Jiangsu Co Ltd
Priority date: 2023-05-19
Filing date: 2023-05-19
Publication date: 2023-12-01
Anticipated expiration: 2033-05-19

Abstract

The utility model provides an automatic switching control circuit, an electric tool and an electric tool system, wherein the automatic switching control circuit comprises a main control chip module which is connected with at least two battery packs; the input end of the control circuit is connected with the main control chip module, and the output end of the control circuit is configured on a power supply path from the battery pack to the electric tool so as to control the connection and disconnection of the battery pack; the input end of the voltage detection circuit is connected to the power supply path from the battery pack to the electric tool, and the output end of the voltage detection circuit is connected with the main control chip module; the main control chip module controls the connection and disconnection of the battery pack through the control circuit based on the feedback of the voltage detection circuit, and when the voltage detection circuit detects that the voltage of the currently connected battery pack is smaller than a preset value, the main control chip module controls the disconnection of the currently connected battery pack and selects the connection of another battery pack.

Description

Automatic switching control circuit, electric tool and electric tool system

Technical Field

The utility model relates to an automatic switching control circuit, an electric tool and an electric tool system, and belongs to the technical field of control circuits.

Background

At present, an automatic switching control circuit is arranged in an electric tool adopting double-pack or multi-pack battery packs in the market to switch different battery packs, and the existing automatic switching control circuit occupies a larger area of a PCB (printed Circuit Board) and is not beneficial to miniaturization design.

In view of the foregoing, it is necessary to provide an automatic switching control circuit, an electric tool, and an electric tool system for solving the above-mentioned problems.

Disclosure of Invention

The utility model aims to provide an automatic switching control circuit, an electric tool and an electric tool system, which can automatically switch different battery packs to supply power.

To achieve the above object, the present utility model provides an automatic switching control circuit comprising:

the main control chip module is connected with at least two battery packs;

the input end of the control circuit is connected with the main control chip module, and the output end of the control circuit is configured on a power supply path from the battery pack to the electric tool so as to control the connection and disconnection of the battery pack;

the input end of the voltage detection circuit is connected to the power supply path from the battery pack to the electric tool, and the output end of the voltage detection circuit is connected with the main control chip module;

The main control chip module is based on feedback of the voltage detection circuit, then controls the connection and disconnection of the battery pack through the control circuit, and when the voltage detection circuit detects that the voltage of the currently connected battery pack is smaller than a preset value, the main control chip module controls the disconnection of the currently connected battery pack and selects the connection of another battery pack.

As a further improvement of the utility model, the control circuit comprises an activation circuit, a trigger circuit and a switch circuit which are sequentially connected in series, wherein the activation circuit is connected with the main control chip module so as to control the activation circuit to be conducted by the main control chip module, and the trigger circuit is activated to drive the switch circuit to control the access state of the battery pack.

As a further improvement of the utility model, the trigger circuit is a trigger which is activated by the activation circuit and generates a self-oscillation signal to drive the switch circuit to control the access state of the battery pack.

As a further improvement of the present utility model, the flip-flop includes a capacitor C1, a capacitor C2, a resistor R3, a nand gate U1A, a nand gate U1B, and a nand gate U1C, where the nand gate U1B and the nand gate U1C are connected in parallel and then connected to the capacitor C3, the resistor R3 is connected in parallel to the nand gate U1A, the nand gate U1A has a first pin Uin and a second pin Uout, and the nand gate U1A is connected to the nand gate U1B through the second pin Uout, the capacitor C1 is connected to the first pin Uin and grounded, and the capacitor C2 is connected to the second pin Uout and grounded.

As a further improvement of the utility model, the oscillation frequency of the trigger is:

wherein VT is ⁺ And VT (VT) ^- A positive threshold voltage and a negative threshold voltage of the trigger circuit, respectively.

As a further improvement of the present utility model, the switching circuit includes a gate circuit and a switching tube Q2 connected in series on a power supply path from the battery pack to the power tool, and the on-state of the battery pack is controlled by turning on and off the switching tube Q2.

As a further improvement of the present utility model, the switching circuit includes a gate circuit and a switching tube Q2 and a switching tube Q3 connected in series on a power supply path from the battery pack to the power tool, the switching tube Q2 is connected in parallel with the switching tube Q3, and one of the switching tube Q2 and the switching tube Q3 is connected in positive and the other of the switching tube Q2 and the switching tube Q3 is connected in negative with the battery pack.

As a further improvement of the utility model, the automatic switching control circuit further comprises a starting circuit, wherein the starting circuit is respectively connected with the battery pack and the main control chip module, and supplies power to the main control chip module after the starting circuit receives a trigger signal from the outside and a driving signal of the main control chip module.

In order to achieve the above object, the present utility model also provides an electric tool provided with an automatic switching control circuit therein, the automatic switching control circuit including:

the main control chip module is connected with at least two battery packs;

the driving circuit module is respectively connected with the main control chip module and the battery pack, and is also connected with the motor so as to drive the motor after the battery pack is connected;

To achieve the above object, the present utility model also provides a power tool system including:

at least two battery packs;

An electric tool, be equipped with automatic switch control circuit in the electric tool, automatic switch control circuit includes:

the main control chip module is connected with at least two battery packs;

The beneficial effects of the utility model are as follows: according to the utility model, at least two control circuits connected in parallel are arranged, the input ends of the control circuits are connected with the main control chip module, and the output ends of the control circuits are configured on a power supply path from the battery pack to the electric tool, so that the main control chip module can control the connection and disconnection of the battery pack through the control circuits based on feedback of the voltage detection circuit, and when the voltage detection circuit detects that the voltage of the currently connected battery pack is smaller than a preset value, the main control chip module controls the disconnection of the currently connected battery pack and selects the connection of another battery pack. Compared with the prior art, the utility model can automatically switch different battery packs to supply power by using the main control chip module, is beneficial to the miniaturization design of the PCB and reduces the overall cost.

Drawings

Fig. 1 is a schematic block diagram of an automatic switching control circuit of the present utility model.

Fig. 2 is a schematic circuit diagram of the starting circuit in fig. 1.

Fig. 3 is a schematic circuit diagram of the first activation circuit in fig. 1.

Fig. 4 is a schematic circuit diagram of the first trigger circuit in fig. 1.

Fig. 5 is a schematic circuit diagram of the first switch circuit in fig. 1.

Fig. 6 is a schematic circuit diagram of the second activation circuit in fig. 1.

Fig. 7 is a schematic circuit diagram of the second trigger circuit in fig. 1.

Fig. 8 is a schematic circuit diagram of the second switch circuit in fig. 1.

Fig. 9 is a schematic circuit diagram of the driving circuit module in fig. 1.

Fig. 10 is a circuit configuration diagram of the voltage detection circuit and the filter circuit in fig. 1.

Fig. 11 is a schematic circuit diagram of an automatic switching control circuit according to the present utility model.

Detailed Description

In order to make the objects, technical solutions and advantages of the present utility model more apparent, the present utility model will be described in detail with reference to the accompanying drawings and specific embodiments.

In this case, in order to avoid obscuring the present utility model due to unnecessary details, only the structures and/or processing steps closely related to the aspects of the present utility model are shown in the drawings, and other details not greatly related to the present utility model are omitted.

In addition, it should be further noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

As shown in fig. 1 to 11, the present utility model discloses a power tool system including a power tool including a main body in which a motor is provided, and a battery pack for supplying power to the power tool to drive the motor to operate. The battery pack is provided with at least two batteries and can supply power to the electric tools respectively.

In the above embodiment, an automatic switching control circuit is provided in the electric tool, and the automatic switching control circuit can switch different battery packs to supply power to the electric tool respectively. Specifically, the battery pack may include a first battery pack, a second battery pack, a third battery pack, a fourth battery pack, or the like, and the present utility model is described by taking the first battery pack and the second battery pack as an example.

As shown in fig. 1, 2, 9 and 11, the automatic switching control circuit includes a driving circuit module, a main control chip module, a control circuit, a voltage detection circuit and a starting circuit, wherein the driving circuit module is connected with the battery pack to supply power to the driving circuit module by the battery pack, and the driving circuit module is also connected with a motor to drive the motor after the battery pack is connected; the main control chip module is respectively connected with the battery pack and the driving circuit module; the starting circuit is respectively connected with the battery pack and the main control chip module, and supplies power to the main control chip module and the driving circuit module after receiving a trigger signal from the outside and a driving signal of the main control chip module.

In a specific embodiment of the present utility model, when the number of the battery packs is two, the battery packs may specifically include a first battery pack and a second battery pack, and two adjacent battery packs are connected in parallel, that is, the first battery pack is connected in parallel with the second battery pack.

Specifically, the first battery pack is provided with first electric connection ends b+ and B-, the second battery pack is provided with second electric connection ends b+ and B-, the main control chip module is provided with a first communication end COM integrated with the first electric connection ends b+ and B-and a second communication end COM integrated with the second electric connection ends b+ and B-, the first battery pack is connected with the first electric connection ends b+ and B-and the second communication end COM, and the second battery pack is connected with the second electric connection ends b+ and B-and the second communication end COM.

The starting circuit is used for connecting the first electric connection end B+ and the second electric connection end B+, and specifically comprises a diode D1, a diode D2, a diode D3, a diode D4, a starting switch S1, a voltage stabilizing diode ZD1, a switch tube 2, a switch tube 3, a switch tube 4 and a voltage reducing circuit, wherein the diode D1, the diode D2, the diode D3 and the diode D4 are sequentially connected in series and connected between the first electric connection end B+ and the second electric connection end B+, namely, the diode D2 is connected with the positive electrode of a first battery pack, the diode D3 is connected with the positive electrode of a second battery pack, the conducting directions of the diode D1 and the diode D2 are the same, the conducting directions of the diode D3 and the diode D4 are the same, the conducting directions of the diode D2 and the diode D3 are opposite, the other end of the starting switch S1 is connected with the positive electrode of the voltage stabilizing diode D1, and the other end of the voltage stabilizing diode D1 is connected between the positive electrode of the starting switch 1 and the positive electrode of the voltage stabilizing module.

The switching tube 1 and the switching tube 2 form a first control switch, the switching tube 3 and the switching tube 4 form a second control switch, the voltage reducing circuit is respectively connected with the first control switch and the second control switch, the switching tube 1 and the switching tube 2 are connected in series and the switching tube 1 is connected to a first electric connection end B+, the switching tube 2 is connected with the main control chip module, the switching tube 3 and the switching tube 4 are connected in series and the switching tube 3 is connected to a second electric connection end B+, the switching tube 4 is connected with the main control chip module, and the voltage reducing circuit is respectively connected with the switching tube 1 and the switching tube 3.

When the starting switch S1 is closed, the anode of the first battery pack provides bias voltage through a diode D1, a diode D2, the starting switch S1 and a voltage stabilizing diode ZD1, so that the switching tube 2 and the switching tube 1 are conducted, a voltage reducing circuit is powered, the voltage reducing circuit generates 15V and 5V output, and power is respectively supplied to a driving circuit module, a main control chip module and the like, so that each circuit module enters a working mode; the positive pole of the second battery pack provides bias voltage through a diode D4, a diode D3, a starting switch S1 and a voltage stabilizing diode ZD1, so that the switching tube 4 and the switching tube 3 are conducted, power is supplied to a voltage reduction circuit, the voltage reduction circuit generates 15V and 5V output, power is supplied to a driving circuit module, a main control chip module and the like respectively, and each circuit module enters a working mode.

The control circuit is provided with at least two control circuits which are connected in parallel, the input end of the control circuit is connected with the main control chip module, and the output end of the control circuit is configured on a power supply path from the battery pack to the electric tool so as to control the connection and disconnection of the battery pack.

The control circuit comprises a switch circuit, a trigger circuit and an activation circuit, wherein the switch circuit comprises a grid circuit connected with the trigger circuit and a switch tube connected in series on a power supply path from a battery pack to an electric tool, the switch circuit is connected with the battery pack through the switch tube, the trigger circuit is connected between the grid circuit and the activation circuit, namely, the trigger circuit is arranged between the switch circuit and the activation circuit, and the activation circuit is connected with the main control chip module, namely, the switch circuit, the trigger circuit and the activation circuit are sequentially connected in series, so that the main control chip module controls the activation circuit to be conducted, the trigger circuit is activated, the switch circuit is driven to control the access state of the battery pack, namely, the grid circuit is driven to work, the switch tube is conducted, and then the corresponding first battery pack/second battery pack is powered. The trigger circuit is a trigger, and preferably a schmitt trigger, and the trigger is activated by the activation circuit and generates a self-oscillation signal to drive the switch circuit to control the access state of the battery pack.

When the battery packs are two, the control circuit is provided with two groups, and the switch circuit, the trigger circuit and the activation circuit are correspondingly provided with two groups. That is, the battery pack includes a first battery pack and a second battery pack, which are connected in parallel; a first switch circuit, a first trigger circuit and a first activation circuit are arranged between the main control chip module and the first battery pack, and the first switch circuit, the first trigger circuit and the first activation circuit are connected in series; the main control chip module is provided with a second switch circuit, a second trigger circuit and a second activation circuit between the main control chip module and the second battery pack, and the second switch circuit, the second trigger circuit and the second activation circuit are connected in series.

As shown in fig. 3 to 5, specifically, the first switching circuit includes a switching tube Q2, a switching tube Q3, a capacitor C4, a resistor R5, a capacitor C5, a diode D5, and a diode D6, wherein the switching tube Q2 and the switching tube Q3 are connected in series with the first battery pack and are connected to a main circuit connected to the driving circuit module, the switching tube Q2 is connected in parallel with the switching tube Q3, and one of the switching tube Q2 and the switching tube Q3 is connected to the first battery pack in positive and the other is connected to the first battery pack in reverse. Of course, the switching tube Q2 may be separately connected in series to a power supply path from the battery pack to the electric tool, and then the connection states of the first battery pack and the second battery pack may be controlled by turning on and off the switching tube Q2.

The capacitor C3, the capacitor C4, the resistor R5, the diode D5 and the diode D6 form a first grid circuit, the capacitor C3, the diode D5 and the resistor R4 are sequentially connected in series and then connected with the switch Q2 and the switch Q3, one end of the capacitor C3 is connected with the trigger circuit, the other end is connected with the diode D5, the cathode of the diode D6 is connected between the capacitor C3 and the diode D5, the diode D6 is connected with the diode D5 in parallel, the conduction directions of the diode D6 and the diode D5 are opposite, the anode of the diode D6 is connected between the switch Q2 and the switch Q3, the capacitor C4 is respectively connected with the cathode of the diode D5 and the anode of the diode D6, one end of the capacitor C4 is connected with the output end of the diode D5, the other end is connected with the input end of the diode D6, the diode D4 is connected with the input end of the diode D5, the input end of the diode D4 is connected with the diode D5, the other end of the diode D4 is connected with the input end of the diode D5, and the resistor R4 is connected with the input end of the diode D4.

In order to normally drive the first switch circuit to work, a trigger circuit is added at the front end of the first gate circuit to generate a self-oscillation signal, namely, a periodically-changed rectangular wave is generated to drive the gate circuit to work, so that the switching tube Q2 and the switching tube Q3 are controlled to be turned on and off.

The first trigger circuit comprises a capacitor C1, a capacitor C2, a resistor R3, a NAND gate U1A, a NAND gate U1B and a NAND gate U1C, wherein the NAND gate U1B and the NAND gate U1C are connected in parallel and then connected with the capacitor C3, namely a third pin of the NAND gate U1B is connected with the capacitor C3, the NAND gate U1A is provided with a first pin Uin and a second pin Uout, the second pin Uout is connected with the third pin of the NAND gate U1B, the resistor R3 is connected with the NAND gate U1A in parallel, the NAND gate U1A is connected with the NAND gate U1B through the second pin Uout, the capacitor C1 is connected with the first pin Uin and grounded, and the capacitor C2 is connected with the second pin Uout and grounded.

The oscillation frequency of the first trigger circuit is as follows:

wherein VT is ⁺ And VT (VT) ^- A positive threshold voltage and a negative threshold voltage of the first trigger circuit, respectively. In the first trigger circuit, the voltage of the first pin Uin is increased when Uin <VT ⁺ The output of the second pin Uout is 15V when Uin>VT ⁺ When the output of the second pin Uout is 0V; the voltage of the first pin Uin is reduced when Uin>VT ^- The output of the second pin Uout is 0V when Uin<VT ^- The output of the second leg Uout is 15V.

The first trigger circuit needs the activation work of the activation circuit of the preceding stage, the first activation circuit is controlled by the main control chip module to be turned on or turned off, the first activation circuit comprises a resistor R1, a resistor R2 and a triode Q1, a collector electrode of the triode Q1 is connected with a first pin Uin of the NAND gate U1A, two ends of the resistor R2 are respectively connected with a base electrode and an emitter electrode of the triode Q1 and the emitter electrode is grounded, and the resistor R1 is respectively connected with the base electrode and the main control chip module.

The second switching circuit comprises a switching tube Q5, a switching tube Q6, a capacitor C9, a capacitor C10, a resistor R9, a resistor R10, a capacitor C11, a diode D7 and a diode D8, wherein the switching tube Q5 and the switching tube Q6 are connected in series with the second battery pack and are connected to the second electric connection end B+, and the switching tube Q5 is connected in parallel with the switching tube Q6 in opposite directions.

The capacitor C9, the capacitor C10, the resistor R9, the resistor R10, the capacitor C11, the diode D7 and the diode D8 form a second grid circuit, the capacitor C9, the diode D7 and the resistor R9 are sequentially connected in series and then connected with the switch tube Q5 and the switch tube Q6, the cathode of the diode D8 is connected between the capacitor C9 and the diode D7, the anode of the diode D8 is connected between the switch tube Q5 and the switch tube Q6, the capacitor C10 is respectively connected with the cathode of the diode D7 and the anode of the diode D8, one end of the resistor R10 is connected between the anode of the diode D8, the other end is connected between the resistor R9 and the switch tube Q5, one end of the capacitor C11 is connected between the anode of the diode D8, and the other end is connected between the resistor R9 and the switch tube Q5.

The second trigger circuit comprises a capacitor C7, a capacitor C8, a resistor R8, a NAND gate U2A, a NAND gate U2B and a NAND gate U2C, wherein the NAND gate U2B and the NAND gate U2C are connected in parallel and then connected with the capacitor C9, namely a third pin of the NAND gate U2B is connected with the capacitor C9, the NAND gate U2A is provided with a first pin Uin and a second pin Uout, the second pin Uout of the NAND gate U2A is connected with the third pin of the NAND gate U2B, the resistor R8 is connected with the NAND gate U2A in parallel, the NAND gate U2A is connected with the NAND gate U2B through the second pin Uout, the capacitor C7 is connected with the first pin Uin and grounded, and the capacitor C8 is connected with the second pin Uout and grounded. It is understood that the oscillation frequency of the second trigger circuit is the same as the oscillation frequency of the first trigger circuit, and will not be described in detail herein.

Referring to fig. 6 to 8, the second activation circuit includes a resistor R6, a resistor R7, and a triode Q4, where a collector of the triode Q4 is connected to the first pin Uin of the nand gate U2A, two ends of the resistor R7 are respectively connected to a base and an emitter of the triode Q4 and the emitter is grounded, and the resistor R6 is respectively connected to the base and the main control chip module.

In the above embodiment, the second switch circuit is the same as the first switch circuit, the second trigger circuit is the same as the first trigger circuit, and the second activation circuit is the same as the first activation circuit. Of course, in other embodiments of the present utility model, the second switch circuit may be different from the first switch circuit, the second trigger circuit may be different from the first trigger circuit, and the second activation circuit may be different from the first activation circuit, which may be specifically set according to needs, and is not limited herein.

As shown in fig. 10, the automatic switching control circuit is further provided with a voltage detection circuit and a filtering circuit, the voltage detection circuit is disposed between the driving circuit module and the battery pack, and the voltage detection circuit is connected with the main control chip module and feeds back the detected voltage to the main control chip module, that is, the input end of the voltage detection circuit is connected to the power supply path from the battery pack to the electric tool, and the output end of the voltage detection circuit is connected with the main control chip module, so that the main control chip module can control the connection and disconnection of the battery pack based on the feedback of the voltage detection circuit, and then the control circuit is used for controlling the connection and disconnection of the battery pack. The filter circuit is arranged between the voltage detection circuit and the driving circuit module, namely the voltage detection circuit and the filter circuit are equivalent to being connected in series.

Specifically, the voltage detection circuit includes a resistor R11, a resistor R12, a resistor R13, and a capacitor C13, where the resistor R11 is connected in series with the resistor R12, and one end of the resistor R11 is connected to the main circuit after the first battery pack and the second battery pack are connected in parallel, that is, the resistor R is located at one side after the first electrical connection end b+ and the second electrical connection end b+ are connected in parallel, the other end of the resistor R12 is grounded, the resistor R13 is connected between the resistor R11 and the resistor R12, and the other end of the resistor R13 is connected to the main control chip module, and the capacitor C13 is connected in parallel to two ends of the resistor R13 and the resistor R12.

The filter circuit comprises a capacitor C14 and a resistor R14, wherein the capacitor C14 is a polar capacitor, the positive electrode of the capacitor C14 is connected to a main circuit formed by connecting the first battery pack and the second battery pack in parallel, namely, the filter circuit is positioned at one side of the first electric connection end B+ and the second electric connection end B+ after being connected in parallel, the negative electrode of the filter circuit is grounded, and the resistor R14 is connected in parallel with the capacitor C14.

The operation flow of the automatic switching control circuit of the present utility model will be described below.

Under the default state, the main control chip module firstly conducts the first battery pack, namely the switching tubes Q2 and Q3 conduct, and secondly conducts the second battery pack, namely the switching tubes Q5 and Q6 conduct, and in the other case, when the first battery pack is not connected to the circuit, the circuit is connected with the second battery pack, the third battery pack, the fourth battery pack and the like, the second battery pack is in priority order, and the like, and the second battery pack works and is controlled in sequence.

When the starting switch S1 is pressed, the power supply of the first battery pack is started, the positive electrode of the first battery pack provides bias voltage through D1, D2, S1 and ZD1, so that the switching tube 2 and the switching tube 1 are conducted, power is supplied to the voltage reducing circuit, the voltage reducing circuit generates 15V and 5V output, power is supplied to the driving circuit module, the main control chip module and the like respectively, and each circuit module enters a working mode.

Similarly, the power supply of the second battery pack is started, namely, the positive electrode of the second battery pack provides bias voltage through D4, D3, S1 and ZD1, so that the switching tube 4 and the switching tube 3 are conducted, power is supplied to the voltage reduction circuit, the voltage reduction circuit generates 15V and 5V output, power is supplied to the driving circuit module, the main control chip module and the like respectively, and each circuit module enters a working mode.

Specifically, when the electric tool is started, the working logic of the electric tool is that a main control chip module firstly sends a high-level single pulse signal of about 1ms to R1, R2 and a triode of a first activation circuitQ1, R1 and R2 form a voltage division bias circuit of the triode Q1, when Ube of the triode Q1 is more than 0.7V, the triode Q1 is conducted, at the moment, a 1 st pin of a NAND gate U1A of a first trigger circuit is pulled to the ground end by the triode Q1 to be 0 level, at the moment, a 2 nd pin output end Uout of the NAND gate U1A is 1 high level, then the 2 nd pin high level charges a capacitor C1 through an R3 resistor in a feedback integration circuit, and as the charging process is carried out, the voltage of the 1 st pin Uin gradually rises, and when the voltage of the 1 st pin Uin rises to VT ⁺ When the trigger circuit is turned over, the output end Uout of the 2 nd pin is 0 low level, at the moment, the capacitor C1 begins to discharge to the R3 resistor, and when the voltage of the 1 st pin Uin is reduced to VT ^- When the circuit is turned over again, the output terminal Uout of the 2 nd pin outputs a high level, and the capacitor C1 starts to charge again, so that the 1 st pin Uin is at VT ⁺ And VT (VT) ^- The output end Uout is continuously changed in height and is changed in a reciprocating manner, so that self-oscillation is formed repeatedly, namely, the periodically-changed rectangular wave with the oscillation frequency f is formed, and the value of R3 or C1 is changed to adjust the output oscillation frequency f.

When the oscillation pulse signal output by the 2 nd pin of the NAND gate U1A passes through the NAND gate U1B and the NAND gate U1C in parallel and turns over again, the 4 th pin of the NAND gate U1B and the 6 th pin of the NAND gate U1C are set to be the point A, the point B is set after passing through the C3 capacitor, the G pole of the Q2 and the Q3 is set to be the point C, when the point A is at the high level for the first time, the C3 capacitor is used for coupling, the coupled high level charges the C4 and the C5 through the D5 and the R4 in the first grid circuit, the C5 voltage is gradually increased, and when the C5 voltage is increased to the threshold voltage of the V GS (th) grid of the switching tube Q2, and similarly, the switching tube Q3 is also simultaneously conducted because the switching tube Q3 is connected with the switching tube Q2 in parallel. Thus, the positive voltage B+ of the first battery pack is connected by Q2 and Q3 to provide power electric energy for the motor main loop, then the positive voltage B+ of the first battery pack is fed back to the point B through the diode D6, and then reaches the point C through the diode D5 and the diode R4, and the voltages of the point B and the point C at the moment are raised to the voltage value B+, namely the voltage value of the first battery pack.

When the second high level at the point a comes, the coupled high level is superposed on the B point potential b+ through the capacitive coupling of C3, so as to form a bootstrap circuit, and the positive voltage b+ of the first battery pack is assumed to be 40V, at this time, the B point potential= (b+) +15v, that is, 40v+15v=55v, and similarly, the C point potential and the B point potential are the same potential, the C point potentials are 55V, the S of Q2 and Q3 are b+=40v, so that the threshold voltages of the V GS (th) gates of Q2 and Q3 are satisfied, and Q2 and Q3 are turned on again, and the switching frequency thereof will operate at the RC oscillation frequency f.

In the working process, the bus voltage is divided by two proper resistors R11 and R12 in the voltage detection circuit, the divided voltage is connected to the AD pin of the main control chip module through a filter circuit consisting of R13 and C13 for detection, and then the bus original voltage is calculated.

When the busbar voltage is detected to be smaller than the undervoltage value and the duration exceeds the set time, the undervoltage protection is entered, namely: the main control chip module detects whether the voltage value of the positive electrode voltage B+ of the second battery pack is less than N x 2.8V, wherein N is the number of the battery cells of the battery pack group, when the voltage value is less than N x 2.8V, the voltage value continuously exceeds 2S, and the first battery pack enters a low-voltage protection action.

When the main control chip module enters a low-voltage protection action, the turn-off logic of the main control chip module is that the main control chip module sends a high level to an R1 resistor pin to enable a triode Q1 in a first activation circuit to be conducted to the ground, at the moment, a 1 st pin of a NAND gate U1A in a first trigger circuit becomes 0, a U1A 2 nd pin becomes high, the U1B and the U1C turn over again, namely an A point becomes 0, a C3 coupling capacitor does not pass through a signal, at the moment, the voltage on the C4 is discharged by an R4 resistor and an R5 resistor, the voltage on the C5 is also discharged by the R5 resistor, and finally the voltage on the C point is 0, so that a switching tube of Q2 and Q3 is simultaneously turned off, and a path of positive voltage B+ of a first battery pack for supplying power to a motor is cut off, thus the discharging task of the first battery pack is ended, the next battery pack is switched to work, namely the second battery pack is switched to work, and the second battery pack works on the principle is the same as the first battery pack, and the following:

At this time, the main control chip module sends a second high-level single pulse signal of about 1ms to R6, R7 and Q4 of the second activation circuit, R6 and R7 form a voltage division bias circuit of the triode Q4, when Ube of the triode Q4 is more than 0.7V, the triode Q4 is conducted, at this time, the 1 st pin of the NAND gate U2A of the second trigger circuit is pulled to the ground end by the triode Q4, namely 0 level, at this time, the 2 nd pin output end of the NAND gate U2AUout is 1 high level, so that the U2A 2 nd pin high level charges the capacitor C7 through the R8 resistor in the feedback integrating circuit, and as the charging process progresses, the U2A 1 st pin Uin voltage gradually rises, and when the U2A 1 st pin Uin voltage rises to VT ⁺ When the circuit of the second trigger circuit is turned over, the output end Uout of the U2A 2 nd pin is 0 low level, at the moment, the capacitor C7 begins to discharge to the R8 resistor, and when the voltage of the U2A 1 st pin Uin is reduced to VT ^- When the circuit is turned over again, the output terminal Uout of the pin 2U 2A outputs a high level, and the capacitor C7 starts to charge again, so that the pin 1U in U2A is at VT ⁺ And VT (VT) ^- The output end Uout is continuously changed in height and is changed in a reciprocating manner, and self-oscillation, namely a periodically-changing rectangular wave is formed in a cycle-to-cycle manner.

When the oscillation pulse signal output by the 2 nd pin of the NAND gate U2A passes through the NAND gate U2B and the NAND gate U2C in parallel and turns over again, the 4 th pin of the NAND gate U2B and the 6 th pin of the NAND gate U2C are set to be a point D, the point D is set to be a point E after passing through a C9 capacitor, the G pole of Q5 and Q6 is set to be a point F, when the point D is at a high level for the first time, C9 capacitive coupling is adopted, the coupled high level charges C10 and C11 through D7 and R9 in a grid circuit, the C11 voltage is gradually increased, and when the C11 voltage is increased to the threshold voltage of the V GS (th) grid of the switch tube Q5, similarly, the switch tube Q6 is also simultaneously conducted because the switch tube Q6 is connected with the switch tube Q5 in parallel. Thus, the positive voltage B+ of the second battery pack is connected by Q5 and Q6 to provide power electric energy for the motor main loop, then the positive voltage B+ of the second battery pack is fed back to the E point through the D8 diode and reaches the F point through the D7 and R9, and the voltages of the E point and the F point at the moment are raised to the voltage value of B+ to obtain the voltage value of the second battery pack.

When the second high level at the point D arrives, the coupled high level is superimposed on the point E potential b+ through the capacitive coupling of C9, so as to form a bootstrap circuit, and assuming that the positive voltage b+ of the second battery pack is 40V, the point E potential= (b+) +15v, that is, 40v+15v=55v at this time, the point F potential and the point E are the same potential, the point F potentials are 55V, the point S of Q5 and Q6 are extremely b+=40v, so that V GS (th) gate threshold voltages of Q5 and Q6 are satisfied, and Q5 and Q6 are turned on again.

At this time, the bus voltage is divided by two proper resistors R11 and R12 in the voltage detection circuit, the divided voltage is connected to the AD pin of the main control chip module through a filter circuit consisting of R13 and C13 for detection, and then the bus original voltage is calculated. When the busbar voltage is detected to be smaller than the undervoltage value and the duration exceeds the set time, the undervoltage protection is entered, namely: the main control chip module detects whether the voltage value of the positive electrode voltage B+ of the second battery pack is less than N x 2.8V, wherein N is the number of the battery cells of the battery pack group, when the voltage value is less than N x 2.8V, the voltage value continuously exceeds 2S, the second battery pack enters a low-voltage protection action, and the main control chip module enters an automatic switching mode.

The turn-off working logic is that the main control chip module sends a high level to the R6 resistor pin, so that the triode Q4 in the second activation circuit is conducted to the ground, the 1 st pin of the NAND gate U2A in the second trigger circuit is changed to 0, the U2A 2 nd pin is changed to high, the D point is changed to 0 after the U2B and the U2C are turned over again, the C9 coupling capacitor has no signal to pass through, the voltage on the C10 is discharged by the R9 resistor and the R10 resistor, the voltage on the C11 is also discharged by the R10 resistor, and finally the voltage on the F point is 0, so that the switching tubes of the Q5 and the Q6 are turned off simultaneously, and the path of the positive voltage B+ of the second battery pack for supplying power to the motor is cut off, so that the second battery pack ends the discharging task.

It should be noted that, in the present utility model, the Q3 and the switching tube Q6 have the function that when the first battery pack works, Q2 and Q3 are turned on, the positive pole b+ of the first battery pack supplies power to the main circuit of the motor, and the switching tube Q6 is started to isolate the first battery pack from flowing backward to the second battery pack because the freewheeling diode in the Q6 is reversely connected to the circuit. When the second battery pack works, Q5 and Q6 are conducted, the positive pole B+ of the second battery pack supplies power to the main circuit of the motor, and as the freewheeling diode in the Q3 is reversely connected to the circuit, the switching tube Q3 is started to isolate the second battery pack from flowing backwards to the first battery pack.

In summary, at least two control circuits connected in parallel are disposed between the driving circuit module and the battery pack, and the input end of the control circuit is connected to the main control chip module, and the output end of the control circuit is configured on the power supply path from the battery pack to the electric tool, so that the main control chip module can control the connection and disconnection of the battery pack through the control circuit based on the feedback of the voltage detection circuit, and when the voltage detection circuit detects that the voltage of the currently connected battery pack is smaller than the preset value, the main control chip module controls the disconnection of the currently connected battery pack and selects the connection of another battery pack. Compared with the prior art, the utility model can automatically switch different battery packs to supply power by using the main control chip module, is beneficial to the miniaturization design of the PCB and reduces the overall cost.

The above embodiments are only for illustrating the technical solution of the present utility model and not for limiting the same, and although the present utility model has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications and equivalents may be made thereto without departing from the spirit and scope of the technical solution of the present utility model.

Claims

1. An automatic switching control circuit, comprising:

the main control chip module is connected with at least two battery packs;

2. The automatic switching control circuit according to claim 1, wherein: the control circuit comprises an activation circuit, a trigger circuit and a switch circuit which are sequentially connected in series, wherein the activation circuit is connected with the main control chip module, so that the main control chip module controls the activation circuit to be conducted, and the trigger circuit is activated to drive the switch circuit to control the access state of the battery pack.

3. The automatic switching control circuit of claim 2, wherein the trigger circuit is a trigger that is activated by the activation circuit and generates a self-oscillation signal to drive the switching circuit to control the access state of the battery pack.

4. The automatic switching control circuit according to claim 3, wherein: the trigger comprises a capacitor C1, a capacitor C2, a resistor R3, a NAND gate U1A, a NAND gate U1B and a NAND gate U1C, wherein the NAND gate U1B and the NAND gate U1C are connected in parallel and then connected with the capacitor C3, the resistor R3 is connected in parallel with the NAND gate U1A, the NAND gate U1A is provided with a first pin Uin and a second pin Uout, the NAND gate U1A is connected with the NAND gate U1B through the second pin Uout, the capacitor C1 is connected with the first pin Uin and grounded, and the capacitor C2 is connected with the second pin Uout and grounded.

5. The automatic switching control circuit of claim 4, wherein the oscillation frequency of the flip-flop is:

6. The automatic switching control circuit according to claim 2, wherein: the switching circuit comprises a gate circuit and a switching tube Q2 connected in series on a power supply path from the battery pack to the electric tool, and the connection state of the battery pack is controlled by the connection and disconnection of the switching tube Q2.

7. The automatic switching control circuit according to claim 2, wherein: the switching circuit comprises a grid circuit, and a switching tube Q2 and a switching tube Q3 which are connected in series on a power supply path from the battery pack to the electric tool, wherein the switching tube Q2 is connected with the switching tube Q3 in parallel, and one of the switching tube Q2 and the switching tube Q3 is connected with the battery pack in a positive way, and the other is connected with the battery pack in a reverse way.

8. The automatic switching control circuit according to claim 1, wherein: the automatic switching control circuit further comprises a starting circuit, the starting circuit is respectively connected with the battery pack and the main control chip module, and when the starting circuit receives a trigger signal from the outside and a driving signal of the main control chip module, the starting circuit supplies power to the main control chip module.

9. An electric tool, wherein an automatic switching control circuit is provided in the electric tool, the automatic switching control circuit comprising:

the main control chip module is connected with at least two battery packs;

10. The power tool of claim 9, wherein: the control circuit comprises an activation circuit, a trigger circuit and a switch circuit which are sequentially connected in series, wherein the activation circuit is connected with the main control chip module, so that the main control chip module controls the activation circuit to be conducted, and the trigger circuit is activated to drive the switch circuit to control the access state of the battery pack.

11. The power tool of claim 10, wherein: the switching circuit comprises a gate circuit and a switching tube Q2 connected in series on a power supply path from the battery pack to the electric tool, and the connection state of the battery pack is controlled by the connection and disconnection of the switching tube Q2.

12. The power tool of claim 10, wherein: the switching circuit comprises a grid circuit, and a switching tube Q2 and a switching tube Q3 which are connected in series on a power supply path from the battery pack to the electric tool, wherein the switching tube Q2 is connected with the switching tube Q3 in parallel, and one of the switching tube Q2 and the switching tube Q3 is connected with the battery pack in a positive way, and the other is connected with the battery pack in a reverse way.

13. A power tool system, comprising:

At least two battery packs;

the main control chip module is connected with at least two battery packs;