Switching circuit, protection chip and protection circuit

Abstract

The present invention discloses a switching circuit, a protection chip and a protection circuit. Wherein, the switching circuit includes a first power supply end connected to the first end of the first resistor, and a second end connected to the non-inverting input end of the first comparator; a second power supply end connected to the first end of the second resistor, and the second end of the second resistor connected to the line between the first resistor and the first comparator; a first end of a voltage divider component connected to the first power supply end, a second end connected to the second power supply end, and the first end is also connected to the inverting input end of the first comparator, the voltage divider component includes a plurality of resistors connected in series in sequence, and at least one resistor is connected in parallel with a control switch; a conversion module is connected to the control end of the control switch, the conversion module receives a trimming signal, converts the trimming signal into a control signal for controlling the on and off of the switch, and adjusts the size of the reference voltage through the control signal. The technical solution of the present application can effectively adjust the threshold voltage after the chip is packaged, reduce the parameter offset, and improve the safety of electronic equipment.

Description

Technical Field

[0001] The present invention relates to the technical field of circuit protection, and in particular to a switching circuit, a protection chip and a protection circuit. Background Art

[0002] Nowadays, various electronic devices have become a part of people's lives. They are usually equipped with batteries to power the electronic devices. To protect the electronic devices, they are also equipped with battery protection circuits to protect the electronic devices from overvoltage.

[0003] Currently, when setting the threshold voltage for overvoltage protection, laser trimming is typically used to adjust the fuse connected in parallel with the resistor, thereby adjusting the resistance of the connected circuit and completing the threshold voltage adjustment. However, laser trimming can only be performed before the chip is packaged. After the chip is packaged, the laser cannot penetrate the chip interior, making the fuse burnout impossible. Furthermore, pre-packaged fuse burnout can easily induce stress during chip assembly, leading to parameter shifts. This can cause the adjusted threshold voltage to shift, compromising the safety of electronic devices. Summary of the Invention

[0004] In view of the defects in the prior art, the present invention provides a switching circuit that can effectively adjust the threshold voltage after chip packaging, reduce parameter deviation, and improve the safety of electronic equipment.

[0005] The present application provides a switching circuit, the switching circuit comprising:

[0006] a first power supply end, the first power supply end being used to provide a first voltage, the first power supply end being connected to a first end of a first resistor, and a second end of the first resistor being connected to a non-inverting input end of a first comparator;

[0007] a second power supply end, the second power supply end being used to provide a second voltage, the first voltage being greater than the second voltage, the second power supply end being connected to a first end of a second resistor, and a second end of the second resistor being connected to a line between the first resistor and the first comparator;

[0008] a switching module, the switching module comprising a voltage divider component, a first end of the voltage divider component being connected to the first power supply terminal, a second end of the voltage divider component being connected to the second power supply terminal, the first end of the voltage divider component being further connected to the inverting input terminal of the first comparator, the voltage divider component being configured to provide a reference voltage to the inverting input terminal of the first comparator, the voltage divider component comprising a plurality of voltage divider resistors connected in series, at least one of the voltage divider resistors being connected in parallel with a control switch;

[0009] A conversion module is connected to the control end of the control switch, the conversion module receives a trimming signal, and the conversion module converts the trimming signal into a control signal for turning the control switch on and off. In response to the control signal, the control switch adjusts the resistance of the voltage divider component connected to the circuit to adjust the reference voltage.

[0010] In one aspect, the side of the voltage-dividing resistor connected to the first power supply end is the first end, the first end of the control switch is connected to the first end of the voltage-dividing resistor in parallel, the side of the voltage-dividing resistor connected to the second power supply end is the second end, and the second end of the control switch is connected to the second end of the voltage-dividing resistor in parallel;

[0011] The conversion module includes: a conversion sub-module, the input end of the conversion sub-module is respectively connected to the first power supply end and the second power supply end, the output end of the conversion sub-module is connected to the control end of the control switch, the conversion sub-module receives the adjustment signal and outputs the control signal based on the adjustment signal, wherein the control signal is the first voltage or the second voltage.

[0012] In one aspect, the conversion submodule includes a first subunit and a second subunit, the first subunit is connected to the first power supply end and the second power supply end respectively, the second subunit is connected to the first power supply end and the second power supply end respectively, the output end of the first subunit is connected to the output end of the second subunit, and the output end of the first subunit and the output end of the second subunit are the output end of the conversion submodule;

[0013] The conversion module further includes: a bias submodule and an inverter, the bias submodule provides a bias voltage, and the bias submodule is respectively connected to the first subunit and the second subunit;

[0014] The first subunit receives the trimming signal and, under the action of the bias voltage, controls the first subunit to output the first voltage;

[0015] The input end of the inverter receives the trimming signal, and the output end of the inverter is connected to the second subunit. The second subunit receives the trimming signal, and under the action of the bias voltage, the trimming signal controls the second subunit to output the second voltage through the inverter.

[0016] In one aspect, the bias submodule includes a bias switch and a first current source, wherein a first end of the bias switch is connected to the second power supply end, a second end of the bias switch is connected to the positive electrode of the first current source, a negative electrode of the first current source is grounded, and a control end of the bias switch is connected to the second end of the bias switch;

[0017] The first subunit includes a first response switch, a second response switch, a third response switch, and a fourth response switch. The control end of the first response switch receives the adjustment signal. The first end of the first response switch is grounded. The first end of the second response switch is connected to the second end of the third response switch. The control end of the second response switch is connected to the second end of the bias switch. The second end of the second response switch is connected to the second end of the first response switch. The first end of the third response switch is connected to the first power supply end. The control end of the third response switch is connected to the first end of the second response switch. The first end of the fourth response switch is connected to the first power supply end. The control end of the fourth response switch is connected to the first end of the second response switch. The second end of the fourth response switch is the output end of the first subunit.

[0018] The second subunit includes a fifth response switch, a sixth response switch, a seventh response switch, and an eighth response switch. The control end of the fifth response switch is connected to the output end of the inverter. The first end of the fifth response switch is grounded. The second end of the fifth response switch is connected to the second end of the sixth response switch. The control end of the sixth response switch is connected to the second end of the bias switch. The first end of the sixth response switch is connected to the second end of the third response switch. The first end of the seventh response switch is connected to the first power supply end. The second end of the seventh response switch is connected to the first end of the second response switch. The control end of the seventh response switch is connected to the first end of the sixth response switch. The control end of the eighth response switch is connected to the first end of the second response switch. The first end of the eighth response switch is connected to the second power supply end. The second end of the eighth response switch is connected to the second end of the fourth response switch. The second end of the eighth response switch is the output end of the second subunit.

[0019] In one aspect, the bias switch, the second response switch, the third response switch, the fourth response switch, the sixth response switch, and the seventh response switch are P-type MOS transistors, the first response switch, the fifth response switch, and the eighth response switch are N-type MOS transistors, and at least the bias switch, the second response switch, and the sixth response switch have the same threshold voltage.

[0020] In one aspect, there are multiple control switches and multiple conversion submodules, the output end of one conversion submodule is connected to one control switch, and multiple conversion submodules are connected to the same bias submodule.

[0021] In one aspect, the switching circuit includes a second current source, which is arranged between the voltage divider component and the first power supply end, the positive pole of the second current source is connected to the first power supply end, and the negative pole of the second current source is connected to the first end of the voltage divider component.

[0022] In one aspect, the switching circuit further includes a ground terminal, a third resistor, a fourth resistor, and a second comparator;

[0023] a first end of the third resistor is connected to the second power supply end, a second end of the third resistor is connected to the non-inverting input end of the second comparator, a first end of the fourth resistor is connected to the second end of the third resistor, and a second end of the fourth resistor is connected to the ground end;

[0024] There are two switching modules, one of which is arranged between the first comparator and the second power supply end, and the other of which is arranged between the second comparator and the ground end.

[0025] In order to solve the above problems, the present application also provides a protection chip, which includes a packaging layer and the switching circuit as described above, and the packaging layer encapsulates and wraps the switching circuit.

[0026] In order to solve the above problems, the present application also provides a protection circuit, which includes the switching circuit as described above, and the protection circuit also includes a battery cell group, a protection switch and a fuse. The output end of the switching circuit is connected to the control end of the protection switch, the first end of the protection switch is connected to the negative pole of the battery cell group, the positive pole of the battery cell group is connected to the fuse, and the second end of the protection switch is connected to the fuse.

[0027] The beneficial effects of the present invention are reflected in the following aspects: by switching the control switch in the switching module on or off, the resistance of the circuit connected to the voltage divider component can be adjusted, thereby adjusting the reference voltage, that is, adjusting the threshold voltage. The conversion module converts the adjustment signal into a control signal, and controls the on-off of the control switch through the control signal, thereby adjusting the resistance of the circuit connected to the voltage divider component. When the resistance changes, the corresponding reference voltage can be adjusted. Therefore, it can be seen that the technical solution of the present application can effectively adjust the threshold voltage after chip packaging, reduce parameter offset, and improve the safety of electronic equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly describes the drawings required for the specific embodiments or the description of the prior art. Similar elements or parts are generally identified by similar reference numerals throughout the drawings. Elements or parts in the drawings are not necessarily drawn to scale.

[0029] Figure 1 This is a schematic diagram of the connection of the switching module of the switching circuit of this application;

[0030] Figure 2 This is a connection diagram of the conversion module in the switching circuit of this application;

[0031] Figure 3 For this application Figure 2 Schematic diagram of the connection of the first subunit;

[0032] Figure 4 For this application Figure 2 Schematic diagram of the connection of the second subunit;

[0033] Figure 5 This is a schematic diagram showing the connection of multiple conversion sub-modules in the switching circuit of this application;

[0034] Figure 6 This is a connection diagram of the trimming circuit control switching circuit in this application;

[0035] Figure 7 This is a connection diagram of two switching modules provided in the switching circuit of this application;

[0036] Figure 8 This is a connection diagram of the protection circuit in this application.

[0037] In the accompanying drawings, 100, a first power supply terminal; 200, a second power supply terminal; 300, a switching module; 400, a conversion module; VDD, a power supply interface; BAT1, a first battery cell; BAT2, a second battery cell; C1, a first capacitor;

[0038] C2, second capacitor; 500, protection chip; 600, fuse; MNCO, protection switch; Ra, first voltage-stabilizing resistor; Rb, second voltage-stabilizing resistor; Rv, third voltage-stabilizing resistor; PTC, positive temperature coefficient resistor; Cv, first voltage-stabilizing capacitor; Cc, second voltage-stabilizing capacitor; R1, first resistor; R2, second resistor; R3, third resistor; R4, fourth resistor; U1, first comparator; U2, second comparator; S1, first control switch;

[0039] S2, second control switch; RT1, first voltage-dividing resistor; RT2, second voltage-dividing resistor; RT3, third voltage-dividing resistor; DA, first trimming signal; DX, Nth trimming signal; DAO, first control signal; DXO, second control signal; VC1, first voltage; VC2, second voltage;

[0040] 310, voltage divider component; 410, conversion submodule; 420, bias submodule; 430, inverter; 411, first subunit; 412, second subunit; T0, bias switch; IB1, first current source; IB2, second current source; T1, first response switch; T2, second response switch; T3, third response switch; T4, fourth response switch; T5, fifth response switch; T6, sixth response switch; T7, seventh response switch; T8, eighth response switch. DETAILED DESCRIPTION

[0041] The following embodiments of the technical solution of the present invention will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention and are therefore only examples and are not intended to limit the scope of protection of the present invention.

[0042] It should be noted that, unless otherwise specified, the technical or scientific terms used in this application should have the common meanings understood by those skilled in the art to which the present invention belongs.

[0043] See Figure 1 and Figure 2 As shown, the present application provides a switching circuit, which includes: a first power supply end 100 , a second power supply end 200 , a switching module 300 and a conversion module 400 .

[0044] The first power supply terminal 100 is used to provide a first voltage VC1. The first power supply terminal 100 is connected to the first end of the first resistor R1. The second end of the first resistor R1 is connected to the non-inverting input terminal of the first comparator U1. The first voltage VC1 can act on the non-inverting input terminal of the first comparator U1 after passing through the first resistor R1.

[0045] The second power supply terminal 200 is used to provide a second voltage VC2. The first voltage VC1 is greater than the second voltage VC2. The second power supply terminal 200 is connected to the first end of the second resistor R2. The second end of the second resistor R2 is connected to the line between the first resistor R1 and the first comparator U1. After passing through the second resistor R2, the second voltage VC2 can also act on the non-inverting input terminal of the first comparator U1. Therefore, it can be seen that one part of the signal at the non-inverting input terminal of the first comparator U1 comes from the first voltage VC1, and the other part comes from the second voltage VC2.

[0046] The switching module 300 includes a voltage divider component 310, the first end of the voltage divider component 310 is connected to the first power supply end 100, the second end of the voltage divider component 310 is connected to the second power supply end 200, and the first end of the voltage divider component 310 is also connected to the inverting input end of the first comparator U1. The voltage divider component 310 is used to provide a reference voltage to the inverting input end of the first comparator U1. The voltage divider component 310 includes several voltage divider resistors connected in series in sequence, and at least one voltage divider resistor is connected in parallel with a control switch; in the voltage divider component 310, each voltage divider resistor can be connected in parallel with a control switch, or only one voltage divider resistor can be connected in parallel with a control switch.

[0047] For example, the voltage dividing component 310 includes a first voltage dividing resistor RT1 , a second voltage dividing resistor RT2 , and a third voltage dividing resistor RT3 . The first control switch S1 is connected in parallel to the second voltage dividing resistor RT2 , and the second control switch S2 is connected in parallel to the third voltage dividing resistor RT3 .

[0048] The conversion module 400 is connected to the control terminal of the control switch. The conversion module 400 receives the adjustment signal and converts the adjustment signal into a control signal that controls the on / off of the switch. In response to the control signal, the control switch adjusts the resistance of the voltage divider component 310 connected to the circuit to adjust the reference voltage. When the control switch is turned on, the corresponding voltage divider resistor is short-circuited and not connected to the circuit, and voltage division cannot be achieved. When the control switch is turned off, the corresponding voltage divider resistor can be connected to the circuit, and the voltage can flow through the corresponding voltage divider resistor.

[0049] By turning the control switch in the switching module 300 on or off, the resistance of the circuit connected to the voltage divider component 310 can be adjusted, thereby adjusting the reference voltage, that is, adjusting the threshold voltage. The conversion module 400 converts the adjustment signal into a control signal, and controls the on-off of the control switch through the control signal, thereby adjusting the resistance of the circuit connected to the voltage divider component 310. When the resistance changes, the corresponding reference voltage can be adjusted. Therefore, it can be seen that the technical solution of the present application can effectively adjust the threshold voltage after chip packaging, reduce parameter offset, and improve the safety of electronic equipment.

[0050] In this application, a control signal can be provided to the control switch by power-on programming, but the operating voltage of the power-on programming burning circuit is usually within a fixed voltage range. Due to the different number of battery cells supplied, the power supply voltage to the electronic device will fluctuate greatly, which makes it difficult for the operating voltage of the burning circuit to adapt to the working voltage of the battery cells.

[0051] To this end, in one embodiment of the present application, the side of the voltage divider resistor connected to the first power supply terminal 100 is the first end, the first end of the control switch is connected to the first end of the corresponding parallel voltage divider resistor, the side of the voltage divider resistor connected to the second power supply terminal 200 is the second end, and the second end of the control switch is connected to the second end of the corresponding parallel voltage divider resistor; it should be further explained that the control switch is usually a MOS (Metal-Oxide-Semiconductor Field-Effect Transistor) tube switch. The first end of the control switch refers to the source, the second end of the control switch refers to the drain, and the control end of the control switch refers to the gate. The threshold voltage of the control switch is usually determined by the voltage difference between the source and the gate. Since the source of the control switch will change under the influence of the first voltage VC1, if a programming circuit with a fixed voltage range is used to control the control switch, when the source variation range is different from the gate, it is easy for the control switch to fail to switch on and off accurately.

[0052] The conversion module 400 includes: a conversion submodule 410, the input end of the conversion submodule 410 is connected to the first power supply end 100 and the second power supply end 200 respectively, the output end of the conversion submodule 410 is connected to the control end of the control switch, the conversion submodule 410 receives the adjustment signal, and outputs the control signal based on the adjustment signal, wherein the control signal is the first voltage VC1 or the second voltage VC2. It can be seen that through the conversion submodule 410, the output is the first voltage VC1 or the second voltage VC2. For example, the first voltage VC1 can turn on the control switch, and the second voltage VC2 can turn off the control switch. Since the first voltage VC1 and the second voltage VC2 are provided by the first power supply end 100 and the second power supply end 200 respectively, they will change with the voltage of the first power supply end 100 and the second power supply end 200. Therefore, the voltage of the control signal can change with the number of battery cells, and is well adapted to the working voltage of the battery cells.

[0053] See Figure 6 As shown, the output voltage module outputs a voltage, and the trimming circuit is used to provide a trimming signal, such as a first trimming signal DA. The first trimming signal DA acts on the switching module 300 and outputs a first control signal DAO. The first control signal DAO can be a first voltage VC1. N trimming signals can be output, where N is an integer greater than or equal to 2. For another example, the Nth trimming signal DX is output. The Nth trimming signal DX acts on the switching module and outputs a second control signal DXO. The second control signal DXO can be a second voltage VC2.

[0054] See Figure 3 and Figure 4As shown, in one embodiment of the present application, the conversion sub-module 410 includes a first sub-unit 411 and a second sub-unit 412, the first sub-unit 411 is respectively connected to the first power supply end 100 and the second power supply end 200, the second sub-unit 412 is respectively connected to the first power supply end 100 and the second power supply end 200, the output end of the first sub-unit is connected to the output end of the second sub-unit 412, the output end of the first sub-unit 412 is connected, and the output end of the first sub-unit 412 and the output end of the second sub-unit 412 are the output ends of the conversion sub-module 410; when the first sub-unit 411 is in effect, the output signal of the conversion sub-module 410 is the output signal of the first sub-unit 411, and similarly when the second sub-unit 412 is in effect, the output signal of the conversion sub-module 410 is the output signal of the second sub-unit 412.

[0055] The conversion module 400 further includes: a bias submodule 420 and an inverter 430 . The bias submodule 420 provides a bias voltage and is connected to the first subunit 411 and the second subunit 412 , respectively. The bias voltage always acts on the first subunit 411 and the second subunit 412 .

[0056] First subunit 411 receives a trimming signal and, under the influence of a bias voltage, controls first subunit 411 to output a first voltage VC1. The trimming signal is received at the input of inverter 430, and after passing through inverter 430, it can be adjusted from a high level to a low level, or vice versa. The output of inverter 430 is connected to second subunit 412, which receives the trimming signal and, under the influence of a bias voltage, controls second subunit 412 to output a second voltage VC2 via inverter 430. Thus, under the control of the bias voltage and inverter 430, either first subunit 411 or second subunit 412 can be operated to output either the first voltage VC1 or the second voltage VC2.

[0057] In one embodiment of the present application, the bias submodule 420 includes a bias switch T0 and a first current source IB1. The configuration of the first current source IB1 can ensure the loading of the bias voltage. A first end of the bias switch T0 is connected to the second power supply terminal 200, a second end of the bias switch T0 is connected to the positive electrode of the first current source IB1, a negative electrode of the first current source IB1 is grounded, and a control end of the bias switch T0 is connected to the second end of the bias switch T0. The first subunit 411 includes a first response switch T1, a second response switch T2, a third response switch T3, and a fourth response switch T4. The control end of the first response switch T1 receives a trimming signal, a first end of the first response switch T1 is grounded, a first end of the second response switch T2 is connected to the second end of the third response switch T3, a control end of the second response switch T2 is connected to the second end of the bias switch T0, a second end of the second response switch T2 is connected to the second end of the first response switch T1, a first end of the third response switch T3 is connected to the first power supply terminal 100, a control end of the third response switch T3 is connected to the first end of the second response switch T2, a first end of the fourth response switch T4 is connected to the first power supply terminal 100, a control end of the fourth response switch T4 is connected to the first end of the second response switch T2, and a second end of the fourth response switch T4 serves as an output end of the first subunit 411.

[0058] The second subunit 412 includes a fifth response switch T5, a sixth response switch T6, a seventh response switch T7, and an eighth response switch T8. The control end of the fifth response switch T5 is connected to the output end of the inverter 430. The first end of the fifth response switch T5 is grounded. The second end of the fifth response switch T5 is connected to the second end of the sixth response switch T6. The control end of the sixth response switch T6 is connected to the second end of the bias switch T0. The first end of the sixth response switch T6 is connected to the second end of the third response switch T3. The first end of the seventh response switch T7 is connected to the first power supply end 100. The second end of the seventh response switch T7 is connected to the first end of the second response switch T2. The control end of the seventh response switch T7 is connected to the first end of the sixth response switch T6. The control end of the eighth response switch T8 is connected to the first end of the second response switch T2. The first end of the eighth response switch T8 is connected to the second power supply end 200. The second end of the eighth response switch T8 is connected to the second end of the fourth response switch T4. The second end of the eighth response switch T8 is the output end of the second subunit 412.

[0059] The first terminal of the bias switch T0 and the first terminal of each response switch are generally referred to as the source. The second terminal of the bias switch T0 and the second terminal of each response switch are generally referred to as the drain. The control terminal of the bias switch T0 and the control terminal of each response switch are generally referred to as the gate.

[0060] In one embodiment of the present application, the bias switch T0, the second response switch T2, the third response switch T3, the fourth response switch T4, the sixth response switch T6, and the seventh response switch T7 are P-type MOS transistors, and the first response switch T1, the fifth response switch T5, and the eighth response switch T8 are N-type MOS transistors. At least the threshold voltages of the bias switch T0, the second response switch T2, and the sixth response switch T6 are the same. If the threshold voltage of the bias switch T0 is Vt, then the threshold voltages of the second response switch T2 and the sixth response switch T6 are also Vt. This ensures that when the bias switch T0 is turned on, the second response switch T2 and the sixth response switch T6 are also turned on. A bias voltage is continuously provided by the first current source IB1, and the bias voltage is VB, where VB = VC2 - |Vt|.

[0061] For example, when the first trim signal DA is high, the first response switch T1 is turned on, the inverter 430 outputs a low level, the fifth response switch T5 is turned off, and the gate of the second response switch T2 is at VB. The second response switch T2 is turned on, and the source of the second response switch T2 is pulled down to VB + |Vt| (equal to VC2 - |Vt| + |Vt| = VC2). This turns on the third response switch T3, which in turn pulls the gate of the seventh response switch T7 up to VC1, turning off the seventh response switch T7. Since the gate voltage of the fourth response switch T4 is also equal to the source voltage of the second response switch T2, the fourth response switch T4 is also turned on, and the output of the fourth response switch T4 is high (equal to the voltage of VC1).

[0062] When the first trim signal DA is at a low level, the first response switch T1 is turned off, the output of the inverter 430 is at a high level, the fifth response switch T5 is turned on, the sixth response switch T6 is turned on, and its source is pulled down to VB + |Vt| (equal to VC2 - |Vt| + |Vt| = VC2). The seventh response switch T7 is turned on, pulling the drain of the seventh response switch T7 to VC2. Since the gate voltage of the fourth response switch T4 is also equal to the drain voltage of the seventh response switch T7, the fourth response switch T4 is turned off, and the eighth response switch T8 is turned on, and the output of the eighth response switch T8 is low (equal to the voltage of VC2).

[0063] See Figure 5 As shown, in one embodiment of the present application, multiple control switches are provided, multiple conversion submodules 410 are provided, the output end of a conversion submodule 410 is connected to a control switch, and multiple conversion submodules 410 are connected to the same bias submodule 420.

[0064] For example, the control switches include a first control switch S1 and a second control switch S2. Two conversion submodules 410 are provided. The output of one conversion submodule 410 is connected to the control terminal of the first control switch S1, and the output of the other conversion submodule 410 is connected to the control terminal of the second control switch S2. The conversion submodules 410 share a bias submodule 420, which reduces the number of circuit components and thus saves power and circuit area. Typically, one inverter 430 is provided for each conversion submodule 410. In the design, the first current source IB1 can use a relatively low current to achieve low power consumption, for example, a current value of 0.5 nanoamperes to 5 microamperes.

[0065] As shown in the figure, in one embodiment of the present application, the switching circuit includes a second current source IB2, which is disposed between the voltage divider component 310 and the first power supply terminal 100. The positive electrode of the second current source IB2 is connected to the first power supply terminal 100, and the negative electrode of the second current source IB2 is connected to the first terminal of the voltage divider component 310. The second current source IB2 continuously provides voltage to ensure the formation of a reference voltage.

[0066] In one embodiment of the present application, the switching circuit further includes a ground terminal, a third resistor R3, a fourth resistor R4, and a second comparator U2; a first end of the third resistor R3 is connected to the second power supply terminal 200, a second end of the third resistor R3 is connected to the non-inverting input terminal of the second comparator U2, a first end of the fourth resistor R4 is connected to the second end of the third resistor R3, and a second end of the fourth resistor R4 is connected to the ground terminal; two switching modules 300 are provided, one switching module 300 is provided between the first comparator U1 and the second power supply terminal 200, and the other switching module 300 is provided between the second comparator U2 and the ground terminal. The conversion module outputs a comparison signal, which controls the on and off of the protection switch MNCO according to the comparison signal, wherein the first comparator outputs a first comparison signal COA, and the second comparator outputs a second comparison signal COB.

[0067] The present application also provides a protection chip 500 , which includes a packaging layer and the switching circuit as described above, wherein the packaging layer encapsulates and wraps the switching circuit.

[0068] The specific embodiments and beneficial effects of the protection chip 500 in this application can be found in the above-mentioned switching circuit, which will not be described in detail here.

[0069] See Figure 8As shown, the present application also provides a protection circuit, which includes the switching circuit as described above, and the protection circuit also includes a battery cell group, a protection switch MNCO and a fuse 600. The output end of the switching circuit is connected to the control end of the protection switch MNCO, the first end of the protection switch MNCO is connected to the negative pole of the battery cell group, the positive pole of the battery cell group is connected to the fuse 600, and the second end of the protection switch MNCO is connected to the fuse 600. The battery cell group includes a first battery cell BAT1 and a second battery cell BAT2; the first battery cell BAT1 and the second battery cell BAT2 are connected in series, the negative electrode of the first battery cell BAT1 is connected to the positive electrode of the second battery cell BAT2, the positive electrode of the battery cell group is connected to one end of the first voltage-stabilizing resistor Ra, the other end of the first voltage-stabilizing resistor Ra is connected to the first power supply end, and one end of the first capacitor C1 is connected to the other end of the first voltage-stabilizing resistor Ra; the positive electrode of the second battery cell BAT2 is connected to one end of the second voltage-stabilizing resistor Rb, the other end of the second voltage-stabilizing resistor Rb is connected to the second power supply end, the other end of the first capacitor C1 is connected between the second voltage-stabilizing resistor Rb and the second power supply end, one end of the second capacitor C2 is connected between the second voltage-stabilizing resistor Rb and the second power supply end, and the other end of the second capacitor C2 is connected to the negative electrode of the second battery cell BAT2 and grounded. One end of the third voltage-stabilizing resistor Rv is connected to the positive electrode of the battery cell group, and the other end of the third voltage-stabilizing resistor Rv is connected to the power supply interface VDD. One end of the first voltage-stabilizing capacitor is connected between the third voltage-stabilizing resistor Rv and the power supply interface VDD, and the other end of the first voltage-stabilizing capacitor is connected between the negative electrode of the battery cell group and the low-voltage interface, which is grounded. One end of the second voltage-stabilizing capacitor is connected between the third voltage-stabilizing resistor Rv and the power supply interface VDD, and the other end of the second voltage-stabilizing capacitor is connected to a positive temperature coefficient resistor, and the other end of the positive temperature coefficient resistor is connected to the positive electrode of the battery cell group. The source of the protection switch MNCO is connected to the negative electrode of the battery cell group, and the drain of the protection switch MNCO is connected to the positive electrode of the battery cell group.

[0070] When the protection chip detects that any cell voltage is overvoltage (for example, the cell voltage is greater than the overvoltage protection threshold, which is 4.5V in one design example), and the detection lasts longer than the protection delay time (for example, 1 second in one design example), the output terminal CO of the protection chip 500 is high, driving the protection switch MNCO, blowing the fuse 600, and cutting off the charging path. When no overvoltage occurs, the cell can be charged by connecting a charger to the P+ and P- terminals. When the battery temperature is too high, the resistance value of the positive temperature coefficient resistor increases, and after voltage division with the internal resistance, the voltage of the CTL node becomes lower. When it is lower than the overtemperature protection threshold, the output terminal CO of the protection chip 500 is high, driving the protection switch MNCO to turn on, blowing the fuse 600, and cutting off the charging path.

[0071] The specific embodiments and beneficial effects of the protection circuit in this application can be found in the above-mentioned switching circuit, which will not be repeated here.

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and description of the present invention.

Claims

1. A switching circuit, characterized in that: The switching circuit includes: a first power supply end, the first power supply end being used to provide a first voltage, the first power supply end being connected to a first end of a first resistor, and a second end of the first resistor being connected to a non-inverting input end of a first comparator; a second power supply end, the second power supply end being used to provide a second voltage, the first voltage being greater than the second voltage, the second power supply end being connected to a first end of a second resistor, and a second end of the second resistor being connected to a line between the first resistor and the first comparator; a switching module, the switching module comprising a voltage divider component, a first end of the voltage divider component being connected to the first power supply terminal, a second end of the voltage divider component being connected to the second power supply terminal, the first end of the voltage divider component being further connected to the inverting input terminal of the first comparator, the voltage divider component being configured to provide a reference voltage to the inverting input terminal of the first comparator, the voltage divider component comprising a plurality of voltage divider resistors connected in series, at least one of the voltage divider resistors being connected in parallel with a control switch; a conversion module connected to the control end of the control switch, the conversion module receiving a trimming signal, the conversion module converting the trimming signal into a control signal for turning the control switch on and off, and the control switch adjusting the resistance of the circuit connected to the voltage divider component in response to the control signal to adjust the reference voltage; The side of the voltage-dividing resistor connected to the first power supply end is a first end, the first end of the control switch is connected to the first end of the voltage-dividing resistor in parallel, the side of the voltage-dividing resistor connected to the second power supply end is a second end, and the second end of the control switch is connected to the second end of the voltage-dividing resistor in parallel; The conversion module includes: a conversion submodule, wherein the input end of the conversion submodule is connected to the first power supply end and the second power supply end respectively, and the output end of the conversion submodule is connected to the control end of the control switch, the conversion submodule receives the adjustment signal, and outputs the control signal based on the adjustment signal, wherein the control signal is the first voltage or the second voltage; The conversion submodule includes a first subunit and a second subunit, the first subunit is connected to the first power supply end and the second power supply end respectively, the second subunit is connected to the first power supply end and the second power supply end respectively, the output end of the first subunit is connected to the output end of the second subunit, and the output end of the first subunit and the output end of the second subunit are the output end of the conversion submodule; The conversion module further includes: a bias submodule and an inverter, the bias submodule provides a bias voltage, and the bias submodule is respectively connected to the first subunit and the second subunit; The first subunit receives the trimming signal and, under the action of the bias voltage, controls the first subunit to output the first voltage; The input end of the inverter receives the trimming signal, and the output end of the inverter is connected to the second subunit. The second subunit receives the trimming signal, and under the action of the bias voltage, the trimming signal controls the second subunit to output the second voltage through the inverter.

2. The switching circuit according to claim 1, wherein: The bias submodule includes a bias switch and a first current source, wherein a first end of the bias switch is connected to the second power supply end, a second end of the bias switch is connected to the positive electrode of the first current source, a negative electrode of the first current source is grounded, and a control end of the bias switch is connected to the second end of the bias switch; The first subunit includes a first response switch, a second response switch, a third response switch, and a fourth response switch. The control end of the first response switch receives the adjustment signal. The first end of the first response switch is grounded. The first end of the second response switch is connected to the second end of the third response switch. The control end of the second response switch is connected to the second end of the bias switch. The second end of the second response switch is connected to the second end of the first response switch. The first end of the third response switch is connected to the first power supply end. The control end of the third response switch is connected to the first end of the second response switch. The first end of the fourth response switch is connected to the first power supply end. The control end of the fourth response switch is connected to the first end of the second response switch. The second end of the fourth response switch is the output end of the first subunit. The second subunit includes a fifth response switch, a sixth response switch, a seventh response switch, and an eighth response switch. The control end of the fifth response switch is connected to the output end of the inverter. The first end of the fifth response switch is grounded. The second end of the fifth response switch is connected to the second end of the sixth response switch. The control end of the sixth response switch is connected to the second end of the bias switch. The first end of the sixth response switch is connected to the second end of the third response switch. The first end of the seventh response switch is connected to the first power supply end. The second end of the seventh response switch is connected to the first end of the second response switch. The control end of the seventh response switch is connected to the first end of the sixth response switch. The control end of the eighth response switch is connected to the first end of the second response switch. The first end of the eighth response switch is connected to the second power supply end. The second end of the eighth response switch is connected to the second end of the fourth response switch. The second end of the eighth response switch is the output end of the second subunit.

3. The switching circuit according to claim 2, wherein: The bias switch, the second response switch, the third response switch, the fourth response switch, the sixth response switch, and the seventh response switch are P-type MOS transistors, the first response switch, the fifth response switch, and the eighth response switch are N-type MOS transistors, and at least the bias switch, the second response switch, and the sixth response switch have the same threshold voltage.

4. The switching circuit according to claim 3, wherein: There are multiple control switches and multiple conversion submodules. The output end of one conversion submodule is connected to one control switch, and multiple conversion submodules are connected to the same bias submodule.

5. The switching circuit according to any one of claims 1 to 4, characterized in that: The switching circuit includes a second current source, which is arranged between the voltage divider component and the first power supply end, the positive electrode of the second current source is connected to the first power supply end, and the negative electrode of the second current source is connected to the first end of the voltage divider component.

6. The switching circuit according to claim 5, wherein: The switching circuit further includes a ground terminal, a third resistor, a fourth resistor and a second comparator; a first end of the third resistor is connected to the second power supply end, a second end of the third resistor is connected to the non-inverting input end of the second comparator, a first end of the fourth resistor is connected to the second end of the third resistor, and a second end of the fourth resistor is connected to the ground end; There are two switching modules, one of which is arranged between the first comparator and the second power supply end, and the other of which is arranged between the second comparator and the ground end.

7. A protection chip, characterized in that: The protection chip includes a packaging layer and the switching circuit according to any one of claims 1 to 6, wherein the packaging layer encapsulates and wraps the switching circuit.

8. A protection circuit, characterized in that: The protection circuit includes the switching circuit according to any one of claims 1 to 6, and the protection circuit also includes a battery cell group, a protection switch and a fuse. The output end of the switching circuit is connected to the control end of the protection switch, the first end of the protection switch is connected to the negative pole of the battery cell group, the positive pole of the battery cell group is connected to the fuse, and the second end of the protection switch is connected to the fuse.

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