CN213402499U - Battery protection circuit - Google Patents
Battery protection circuit Download PDFInfo
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- CN213402499U CN213402499U CN202022087473.3U CN202022087473U CN213402499U CN 213402499 U CN213402499 U CN 213402499U CN 202022087473 U CN202022087473 U CN 202022087473U CN 213402499 U CN213402499 U CN 213402499U
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Abstract
The utility model provides a battery protection circuit adds clamping circuit on current battery protection circuit, clamping circuit's first end with the mains voltage sampling point is connected, and the second end connects in ground with the negative pole of battery altogether, the third end with the return current sampling point is connected, the return current sampling point is located the negative pole of charging source or load side. The clamping circuit receives electric energy from a power supply voltage sampling point, detects a voltage value on the loop current sampling point, and clamps the loop current sampling point when negative high voltage appears at the loop current sampling point, so that the problem that the low-voltage switch tube is broken down by the negative high voltage to damage a chip is effectively solved, high withstand voltage of a battery protection chip is realized while the low-voltage switch tube is used, and the area and the cost of the chip are reduced.
Description
Technical Field
The utility model relates to the field of electronic technology, especially, relate to a battery protection circuit.
Background
The existing battery protection chip internally comprises an over-discharge protection circuit and an over-charge protection circuit for detecting the voltage of a battery, a discharge over-current protection circuit, a charge over-current protection circuit and a short-circuit protection circuit for detecting the current of a loop, and a switch tube control module for controlling the on-off of a charge-discharge switch tube, so that the charge-discharge protection of the battery is realized. However, the switching tube in the existing battery protection chip mainly adopts a low-voltage MOS tube, the withstand voltage of the device is about 10V, and when a user inserts a high-voltage charger of 20V by mistake or a loop current sampling point VM generates surge voltage, the switching tube is easily damaged, so that the battery protection chip cannot work normally. And the chip area and the cost are greatly increased by replacing the switching tube with a high-voltage resistant tube.
SUMMERY OF THE UTILITY MODEL
The utility model provides a battery protection circuit to solve the problem that current battery protection circuit use low-voltage switch pipe to be punctured when easy and damage the chip, increase chip area and cost when using high-voltage switch pipe the utility model discloses a realize like this, a battery protection circuit, include:
the circuit comprises a reference and bias circuit, a voltage protection circuit, a current protection circuit, a delay circuit, a switching tube control circuit, a switching tube and a clamping circuit;
the first end of the voltage protection circuit is connected with a power supply voltage sampling point, and the second end of the voltage protection circuit is connected with the first end of the delay circuit;
the first end of the current protection circuit is connected with the loop current sampling point, and the second end of the current protection circuit is connected with the second end of the delay circuit;
the second end of the delay circuit is connected with the first end of the switch tube control circuit;
the second end of the switch tube control circuit is connected with the grid electrode of the switch tube;
the source electrode and the drain electrode of the switching tube are connected in series in a charge-discharge loop between the battery and a charging power supply or a load;
the first end of the clamping circuit is connected with the power supply voltage sampling point, the second end of the clamping circuit is connected with the negative electrode of the battery in common, and the third end of the clamping circuit is connected with the loop current sampling point;
the loop current sampling point is positioned at the negative pole of the charging power supply or the load side;
the reference and bias circuit is connected with the power supply voltage sampling point;
the reference and bias circuit is used for generating bias voltage required by the voltage protection circuit and bias current required by the current protection circuit; the voltage protection circuit is used for detecting power supply voltage and generating a detection turning signal when the power supply voltage is abnormal; the current protection circuit is used for detecting the charging current and the discharging current and generating a detection turnover signal when the charging current and the discharging current are abnormal; the delay circuit is used for carrying out delay processing on the detection overturning signal; the switch tube control circuit is used for generating a control signal according to an output signal of the delay circuit and sending the control signal to the switch tube so as to control the switch tube to be started or closed; the clamping circuit is used for clamping the loop current sampling point when the negative high voltage appears at the loop current sampling point.
Optionally, when the clamping circuit operates, a voltage drop between the second end and the third end of the clamping circuit is smaller than a source-drain breakdown voltage of the switching tube.
Optionally, the clamping circuit comprises an NMOS transistor and a diode string group, wherein the diode string group comprises a plurality of diodes connected in series with each other;
the drain electrode of the NMOS tube is connected with the power supply voltage sampling point, the grid electrode of the NMOS tube is connected with the negative electrode of the battery in common, and the source electrode of the NMOS tube is connected with the positive electrode of the diode string;
and the cathode of the diode string is connected with the loop current sampling point.
Optionally, the sum of the threshold voltage of the NMOS transistor and the turn-on voltages of the plurality of diodes is smaller than the source-drain breakdown voltage of the switch transistor.
Optionally, the clamping circuit includes an NMOS tube string set, where the NMOS tube string set includes a plurality of NMOS tubes connected in series with each other;
the source electrode of each NMOS tube is connected with a common contact between the drain electrode and the grid electrode of the next NMOS tube;
the drain electrode of the first NMOS tube is connected with the power supply voltage sampling point, and the grid electrode and the negative electrode of the battery are connected to the ground in common;
and the source electrode of the last NMOS tube is connected with the loop current sampling point.
Optionally, the sum of the threshold voltages of the plurality of NMOS transistors is smaller than the source-drain breakdown voltage of the switch transistor.
Optionally, the clamping circuit includes an NMOS transistor and a PMOS transistor string, where the PMOS transistor string includes a plurality of PMOS transistors connected in series;
the drain electrode of the NMOS tube is connected with the power supply voltage sampling point, the grid electrode of the NMOS tube is connected with the negative electrode of the battery in common, and the source electrode of the NMOS tube is connected with the source electrode of the first PMOS tube in the PMOS tube string;
in the PMOS tube string group, a common contact between the grid electrode and the drain electrode of each PMOS tube is connected with the source electrode of the next PMOS tube, and a common contact between the grid electrode and the drain electrode of the last PMOS tube is connected with the loop current sampling point.
Optionally, the sum of the threshold voltage of the NMOS transistor and the threshold voltages of the PMOS transistors is smaller than the source-drain breakdown voltage of the switch transistor.
Optionally, the switching tube control circuit includes a logic circuit, a substrate switching circuit, and a gate control circuit;
the input end of the logic circuit is connected with the second end of the delay circuit, the first output end of the logic circuit is connected with the first end of the substrate switching circuit, and the second output end of the logic circuit is connected with the first end of the grid control circuit;
the second end of the substrate switching circuit is connected with the substrate of the switch tube;
the output end of the grid control circuit is connected with the grid of the switching tube;
the logic circuit is used for carrying out logic processing on an output signal of the delay circuit, generating a substrate switching signal, sending the substrate switching signal to the substrate switching circuit, generating a control signal and sending the control signal to the grid control circuit; the substrate switching circuit is used for switching the substrate polarity of the switching tube according to the substrate switching signal; the grid control circuit is used for outputting a grid control signal to the switching tube according to the control signal so as to control the grid of the switching tube to be started or closed.
Optionally, the switch tube is an isolated MOSFET or a non-isolated MOSFET.
The utility model provides a battery protection circuit adds clamping circuit on current battery protection circuit, clamping circuit's first end with the mains voltage sampling point is connected, and the second end connects in ground with the negative pole of battery altogether, the third end with the return current sampling point is connected, the return current sampling point is located the negative pole of charging source or load side. The clamping circuit receives electric energy from a power supply voltage sampling point, detects a voltage value on the loop current sampling point, and clamps the loop current sampling point when negative high voltage appears at the loop current sampling point, so that the problem that the low-voltage switch tube is broken down by the negative high voltage to damage a chip is effectively solved, high withstand voltage of a battery protection chip is realized while the low-voltage switch tube is used, and the area and the cost of the chip are reduced.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the embodiments or the prior art descriptions will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without inventive labor.
Fig. 1 is a schematic diagram of a battery protection circuit according to an embodiment of the present invention;
fig. 2 is a schematic diagram of a switch tube in a battery protection circuit according to an embodiment of the present invention;
fig. 3 is a schematic diagram of a clamp circuit in a battery protection circuit according to an embodiment of the present invention;
fig. 4 is a schematic diagram of a clamp circuit in a battery protection circuit according to another embodiment of the present invention;
fig. 5 is a schematic diagram of a clamp circuit in a battery protection circuit according to another embodiment of the present invention;
fig. 6 is a schematic diagram of an application of a battery protection circuit according to another embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
The utility model provides a battery protection circuit adds clamping circuit on current battery protection circuit, clamping circuit's first end with the mains voltage sampling point is connected, and the second end connects in ground with the negative pole of battery altogether, the third end with the return current sampling point is connected, the return current sampling point is located the negative pole of charging source or load side. The clamping circuit receives electric energy from a power supply voltage sampling point, detects a voltage value on the loop current sampling point, and clamps the loop current sampling point when negative high voltage appears at the loop current sampling point, so that the problem that the low-voltage switch tube is broken down by the negative high voltage to damage a chip is effectively solved, high withstand voltage of a battery protection chip is realized while the low-voltage switch tube is used, and the area and the cost of the chip are reduced.
Fig. 1 is a schematic diagram of a battery protection circuit according to an embodiment of the present invention. As shown in fig. 1, the battery protection circuit 1 includes a reference and bias circuit 10, a voltage protection circuit 20, a current protection circuit 30, a delay circuit 40, a switching tube control circuit 50, a switching tube 60, and a clamping circuit 70;
the first end of the voltage protection circuit 20 is connected with a power supply voltage sampling point VDD, and the second end is connected with the first end of the delay circuit 40;
a first end of the current protection circuit 30 is connected with the loop current sampling point VM, and a second end is connected with a second end of the delay circuit 40;
the second end of the delay circuit 40 is connected with the first end of the switch tube control circuit 50;
a second end of the switching tube control circuit 50 is connected to the gate of the switching tube 60;
the source and drain of the switching tube 60 are connected in series in a charge-discharge loop between the battery and a charging power supply or a load;
a first end of the clamping circuit 70 is connected with the power supply voltage sampling point VDD, a second end and the negative electrode of the battery are connected with the ground VSS in common, and a third end is connected with the loop current sampling point VM;
the loop current sampling point VM is positioned at the negative electrode of the charging power supply or the load side;
the reference and bias circuit 10 is connected with the power supply voltage sampling point VDD;
the reference and bias circuit 10 is used for generating a bias voltage required by the voltage protection circuit 20 and a bias current required by the current protection circuit 30; the voltage protection circuit 20 is configured to detect a power supply voltage and generate a detection inversion signal when the power supply voltage is abnormal; the current protection circuit 30 is configured to detect a charging current and a discharging current, and generate a detection inversion signal when the charging current and the discharging current are abnormal; the delay circuit 40 is configured to perform delay processing on the detection flipping signal; the switching tube control circuit 50 is configured to generate a control signal according to an output signal of the delay circuit 40, and send the control signal to the switching tube 60 to control the switching tube 60 to be turned on or off; the clamping circuit 70 is used for clamping the loop current sampling point VM when the loop current sampling point VM has a negative high voltage.
Here, the reference and bias circuit 10 is connected to a power supply voltage sampling point VDD. And the power supply voltage sampling point VDD is a voltage sampling point of the power supply anode of the battery protection chip. The method is applied to a battery protection chip, and the power supply voltage sampling point VDD is a voltage sampling point of the battery anode after passing through a preset resistor, such as VDD shown in fig. 1. The loop current sampling point VM is a current sampling point of a charge-discharge loop between a battery and a charging power supply or a load, such as VM shown in fig. 1, and is arranged at the negative electrode of the charging power supply or the load. The reference and bias circuit 10 obtains a voltage sampling value of a chip power supply from a power supply voltage sampling point VDD, and then generates a bias voltage and a bias current according to the voltage sampling value. Wherein the bias voltage is a detection threshold of the voltage protection circuit 20, and the bias current is a detection threshold of the current protection circuit 30.
When the voltage protection circuit 20 is enabled, the power supply voltage is detected, the power supply voltage is compared with the bias voltage to judge whether the battery is over-discharged or over-charged, and a detection turning signal is generated when the power supply voltage is abnormal. When the current protection circuit 30 is enabled, the charging current and the discharging current are detected, the charging current and the discharging current are respectively compared with the corresponding bias current to judge whether the loop is over-discharged or over-charged or short-circuited, and a detection turning signal is generated when the charging current and the discharging current are abnormal. The delay circuit 40 performs delay processing on the detection inversion signal sent by the voltage protection circuit 20 or the current protection circuit 30, and outputs the detection inversion signal after the delay processing to the switching tube control circuit 50. The switching tube control circuit 50 performs logic processing on the output signal of the delay circuit 40 to generate a control signal for the switching tube 60. Wherein, the control signal is a switching signal of the switching tube 60 to control the on/off of the switching tube 60. The switch tube 60 is connected in series in a charge-discharge loop between the battery and a charging power supply or a load, and the protection of voltage overcharge or overdischarge, loop overdischarge or overcharge or short circuit is realized by controlling the start or the close of the switch tube 60.
The clamping circuit 70 receives electric energy from a power supply voltage sampling point VDD, detects voltage information of the loop current sampling point VM, and clamps the loop current sampling point VM when negative high voltage occurs in the loop current sampling point VM. In this embodiment, when the clamping circuit 70 operates, a voltage drop between the second terminal and the third terminal is smaller than a source-drain breakdown voltage of the switching tube 60. Since the second terminal of the clamp circuit 70 and the negative electrode of the battery are connected to the ground VSS in common, the absolute value of the voltage at the third terminal of the clamp circuit 70, that is, the absolute value of the voltage at the sampling point VM of the loop current, is smaller than the breakdown voltage between the source and the drain of the switch 60, thereby preventing the source and the drain of the switch 60 from being broken down.
For example, for easy understanding, a low voltage switching tube of 5V is used as an example for the following description. The breakdown voltage VDS between the source and the drain of the switching tube 60 is about 10V, and the cell voltage is 4V. When the battery protection chip is normally used, the potential at the loop current sampling point VM approaches the voltage VSS of the negative electrode of the battery, and at this time, the clamp circuit 70 does not operate. When the battery is connected to a high-voltage charger, for example, a 20V charger, if the battery voltage is 4V, the voltage at the loop current sampling point VM is-16V high voltage, and the potentials of the three poles of the switching tube 60 are as shown in fig. 2, where VSS represents the drain, VM represents the source, and SW represents the gate. The voltage difference between the drain and the source of the switch tube 60 is 16V, which is greater than the breakdown voltage VDS between the source and the drain, and when the clamp circuit 70 is not provided, the switch tube 60 is broken down and burned, and the battery protection chip fails. The embodiment of the utility model provides a through introducing clamping circuit 70 in return circuit current sampling point VM department, clamp return circuit current sampling point VM's negative voltage when inserting high-pressure charger, make the absolute value of return circuit current sampling point VM's negative voltage be less than breakdown voltage between the source drain of switch tube 60, for example, clamp to-4V, the voltage difference between the drain of switch tube 60 and the source electrode is 4V, is far less than breakdown voltage VDS between the source drain. The switch 60 is not damaged by breakdown and the battery protection chip can still work normally.
It is visible, the embodiment of the utility model provides a through clamp circuit 70 it is right when the negative high pressure appears in return circuit current sampling point VM carries out the clamping and handles, has realized the high withstand voltage of battery protection chip when using the low-voltage switch tube, has guaranteed the high withstand voltage and the reliability of chip when reducing battery protection chip area and cost.
Optionally, as mentioned above, when the clamping circuit 70 works, a voltage drop between the second end and the third end is smaller than the source-drain breakdown voltage VDS of the switching tube. As an embodiment, the clamping circuit 70 includes an NMOS transistor M1 and a diode string, the diode string includes several diodes connected in series;
the drain electrode of the NMOS tube M1 is connected with the power supply voltage sampling point, the grid electrode of the NMOS tube M1 is connected with the cathode of the battery in common, and the source electrode of the NMOS tube M1 is connected with the anode of the diode string group;
and the cathode of the diode string is connected with the loop current sampling point.
Here, when the clamping circuit 70 operates, a voltage drop between the gate of the NMOS transistor M1 and the cathode of the diode string is smaller than the source-drain breakdown voltage VDS of the switching transistor. The number of the diodes in the diode string group can be set according to the actual value of the source-drain breakdown voltage VDS of the switch tube, as long as the sum of the threshold voltage of the NMOS tube and the conduction voltages of the diodes is less than the source-drain breakdown voltage of the switch tube.
For the convenience of understanding, taking the example of the low-voltage switch tube of 5V as an example, it is assumed that the breakdown voltage VDS between the source and the drain of the switch tube is about 10V, and the battery voltage is 4V. As shown in fig. 3, if the diode string includes three diodes connected in series, the three diodes are denoted as a first diode D1, a second diode D2, and a third diode D3. The drain electrode of the NMOS tube M1 is connected with the power supply voltage sampling point, the grid electrode of the NMOS tube M1 is connected with the cathode of the battery in common, and the source electrode of the NMOS tube M1 is connected with the anode of the first diode D1; the cathode of the first diode D1 is connected with the anode of the second diode D2, the cathode of the second diode D2 is connected with the anode of the third diode D3, and the cathode of the third diode D3 is connected with the loop current sampling point VM. The on-state voltages of the NMOS tube M1, the first diode D1, the second diode D2 and the third diode D3 are all 1V, and are 4V in total. When the battery protection chip is normally used, the potential at the loop current sampling point VM is close to the voltage VSS of the negative electrode of the battery, at the moment, VM is greater than VSS-4V, and the NMOS tube M1 and the diode string in the clamping circuit 70 are not conducted. When the battery is connected to a high-voltage charger, for example, a 20V charger, at this time, VM is 4-20-16V, VSS-4V is-4V, and VM is VSS-4V, the NMOS transistor M1 and the diode string in the clamping circuit 70 are turned on, and after the switching on, the voltage of the loop current sampling point VM is pulled up to-4V, so that the voltage difference between the drain and the source of the switching tube is 4V, which is much smaller than the breakdown voltage VDS between the source and the drain, and the damage of the switching tube 60 is avoided. It should be understood that the number of the diodes is only one preferred example of the present invention, and can be specifically set according to actual situations.
As an embodiment, the clamping circuit 70 includes an NMOS transistor string set, where the NMOS transistor string set includes a plurality of NMOS transistors connected in series;
the source electrode of each NMOS tube is connected with a common contact between the drain electrode and the grid electrode of the next NMOS tube;
the drain electrode of the first NMOS tube is connected with the power voltage sampling point, the grid electrode and the negative electrode of the battery are connected to the ground in common,
and the source electrode of the last NMOS tube is connected with the loop current sampling point.
Here, when the clamp circuit 70 operates, a voltage drop between the gate of the first NMOS transistor and the source of the last NMOS transistor is smaller than the source-drain breakdown voltage VDS of the switch transistor. The number of the NMOS tubes in the NMOS tube string group can be set according to the actual value of the source-drain breakdown voltage VDS of the switch tube as long as the sum of the threshold voltages of the NMOS tubes is smaller than the source-drain breakdown voltage of the switch tube.
For the convenience of understanding, taking the example of the low-voltage switch tube of 5V as an example, it is assumed that the breakdown voltage VDS between the source and the drain of the switch tube is about 10V, and the battery voltage is 4V. As shown in fig. 4, if the NMOS transistor string set includes four NMOS transistors connected in series, it is marked as a first NMOS transistor M1, a second NMOS transistor M2, a third NMOS transistor M3, and a fourth NMOS transistor M4. The drain electrode of the first NMOS tube M1 is connected with the power supply voltage sampling point, the grid electrode of the first NMOS tube M1 is connected with the negative electrode of the battery in common, and the source electrode of the first NMOS tube M2 is connected with the common junction point between the drain electrode and the grid electrode of the second NMOS tube M2; the source electrode of the second NMOS tube M2 is connected with the common junction between the drain electrode and the grid electrode of the third NMOS tube M3; the source electrode of the third NMOS tube M3 is connected with the common junction between the drain electrode and the gate electrode of the fourth NMOS tube M4; the source electrode of the fourth NMOS tube M4 is connected with the loop current sampling point VM. The threshold voltages of the first NMOS transistor M1, the second NMOS transistor M2, the third NMOS transistor M3 and the fourth NMOS transistor M4 are all 1V, and are 4V in total. When the battery protection chip is normally used, the potential at the loop current sampling point VM is close to the voltage VSS of the negative electrode of the battery, at this time, VM is greater than VSS-4V, and the first NMOS transistor M1, the second NMOS transistor M2, the third NMOS transistor M3 and the fourth NMOS transistor M4 in the clamping circuit 70 are all not conductive. When the battery is connected to a high-voltage charger, for example, a 20V charger, at this time, VM is 4-20-16V, VSS-4V is-4V, and VM is < VSS-4V, the first NMOS transistor M1, the second NMOS transistor M2, the third NMOS transistor M3, and the fourth NMOS transistor M4 in the clamping circuit 70 are turned on, and after the switching on, the voltage of the loop current sampling point VM is pulled up to-4V, so that the voltage difference between the drain and the source of the switching transistor is 4V, which is much smaller than the breakdown voltage VDS between the source and the drain, and the damage of the switching transistor 60 is avoided. It should be understood that the number of the NMOS transistors is only a preferred example of the present invention, and can be specifically set according to practical situations.
As an embodiment, the clamping circuit 70 includes an NMOS transistor and a PMOS transistor string, where the PMOS transistor string includes a plurality of PMOS transistors connected in series;
the drain electrode of the NMOS tube is connected with the power supply voltage sampling point, the grid electrode of the NMOS tube is connected with the negative electrode of the battery in common, and the source electrode of the NMOS tube is connected with the source electrode of the first PMOS tube in the PMOS tube string;
in the PMOS tube string group, a common contact between the grid electrode and the drain electrode of each PMOS tube is connected with the source electrode of the next PMOS tube, and a common contact between the grid electrode and the drain electrode of the last PMOS tube is connected with the loop current sampling point.
When the clamping circuit 70 is in operation, the voltage drop between the common junction of the gate of the NMOS transistor and the gate and the drain of the last PMOS transistor is less than the source-drain breakdown voltage VDS of the switching transistor. The number of the PMOS tubes in the PMOS tube string group can be set according to the actual value of the source-drain breakdown voltage VDS of the switch tube, as long as the sum of the threshold voltage of the NMOS tube and the threshold voltages of the PMOS tubes is less than the source-drain breakdown voltage of the switch tube.
For the convenience of understanding, taking the example of the low-voltage switch tube of 5V as an example, it is assumed that the breakdown voltage VDS between the source and the drain of the switch tube is about 10V, and the battery voltage is 4V. As shown in fig. 5, the clamping circuit 70 includes an NMOS transistor M1 and a PMOS transistor string, and if the PMOS transistor string includes three PMOS transistors connected in series, it is denoted as a first PMOS transistor M2, a second PMOS transistor M3, and a third PMOS transistor M4. The drain electrode of the NMOS transistor M1 is connected with the power supply voltage sampling point, the grid electrode of the NMOS transistor M1 is connected with the negative electrode of the battery in common, and the source electrode of the NMOS transistor M2 is connected with the source electrode of the first PMOS transistor M2; a common joint between the grid electrode and the drain electrode of the first PMOS tube M2 is connected with the source electrode of the second PMOS tube M3; a common joint between the grid electrode and the drain electrode of the second PMOS tube M3 is connected with the source electrode of the third PMOS tube M4; and a common joint between the grid electrode and the drain electrode of the third PMOS pipe M4 is connected with the loop current sampling point. The threshold voltages of the NMOS transistor M1, the first PMOS transistor M2, the second PMOS transistor M3 and the third PMOS transistor M4 are all 1V, and are 4V in total. When the battery protection chip is normally used, the potential at the loop current sampling point VM is close to the voltage VSS of the negative electrode of the battery, at the moment, VM is greater than VSS-4V, and the NMOS tube M1, the first PMOS tube M2, the second PMOS tube M3 and the third PMOS tube M4 in the clamping circuit 70 are not conducted. When the battery is connected to a high-voltage charger, for example, a 20V charger, at this time, VM is 4-20-16V, VSS-4V is-4V, and VM is less than VSS-4V, the NMOS transistor M1, the first PMOS transistor M2, the second PMOS transistor M3, and the third PMOS transistor M4 in the clamping circuit 70 are turned on, and after the switching on, the voltage intensity line of the loop current sampling point VM is pulled up to-4V, so that the voltage difference between the drain and the source of the switching transistor is 4V, which is much smaller than the breakdown voltage VDS between the source and the drain, and the damage of the switching transistor 60 is avoided. It should be understood that the number of the PMOS transistors is only a preferred example of the present invention, and can be specifically set according to practical situations.
Optionally, in this embodiment, the source and the drain of the switching tube 60 are symmetrical. The switch tube control circuit 50 outputs a substrate switching signal and a control signal to indicate the on or off of the switch tube 60. Optionally, as shown in fig. 6, an application schematic diagram of the battery protection circuit provided in this embodiment is provided. After the battery passes through the preset resistor R4 and the preset capacitor C1, the battery provides a power supply voltage VDD to the battery protection circuit.
The switch tube control circuit 50 comprises a logic circuit 51, a substrate switching circuit 52 and a gate control circuit 53;
an input end of the logic circuit 51 is connected to a second end of the delay circuit 40, a first output end is connected to a first end of the substrate switching circuit 52, and a second output end is connected to a first end of the gate control circuit 53;
a second end of the substrate switching circuit 52 is connected to the substrate of the switch tube;
the output end of the grid control circuit 53 is connected with the grid of the switching tube;
the logic circuit 51 is configured to perform logic processing on an output signal of the delay circuit 40, generate a substrate switching signal, send the substrate switching signal to the substrate switching circuit 52, generate a control signal, and send the control signal to the gate control circuit 53; the substrate switching circuit 52 is configured to switch the substrate polarity of the switching tube 60 according to the substrate switching signal; the gate control circuit 53 is configured to output a gate control signal to the switching tube 60 according to the control signal, so as to control the gate of the switching tube 60 to be turned on or off.
Here, the logic circuit 51, upon receiving the output signal of the delay circuit 40, performs logic processing on the output signal, generates a substrate switching signal and transmits the substrate switching signal to the substrate switching circuit 52, and generates a control signal and transmits the control signal to the gate control circuit 53. The substrate switching circuit 52 switches the substrate polarity of the switch transistor 60 according to the substrate switching signal, so as to select the switch transistor 60 as an N-type substrate or a P-type substrate. The gate control circuit 53 controls the on/off of the gate of the switching tube 60 according to the control signal, so as to protect the charging and discharging of the battery.
Optionally, as a preferred example of the present invention, as shown in fig. 6, the voltage protection circuit 20 includes a first resistor R1, a second resistor R2, a third resistor R3, an over-discharge protection circuit 21, and an over-charge protection circuit 22;
the first end of the over-discharge protection circuit 21 is connected with the common junction point between the first resistor R1 and the second resistor R2, and the second end is connected with the delay circuit 40;
the first end of the overcharge protection circuit 22 is connected to the common junction between the second resistor R2 and the third resistor R3, and the second end is connected to the delay circuit 40;
the other end of the first resistor R1 is connected with a power supply voltage sampling point; the other end of the third resistor R3 is connected with the negative electrode of the battery in common;
the over-discharge protection circuit 21 is configured to obtain a power supply voltage from the power supply voltage sampling point, and send a detection flipping signal to the delay circuit 40 when the power supply voltage is smaller than a first voltage threshold; the overcharge protection circuit 22 is configured to obtain a power supply voltage from the power supply voltage sampling point, and send a detection rollover signal to the delay circuit 40 when the power supply voltage is greater than a second voltage threshold.
Here, the first voltage threshold is a discharge protection voltage threshold, and is a criterion for determining whether or not the battery is over-discharged. The second voltage threshold is a charge protection voltage threshold and is a standard for judging whether the battery is overcharged.
When the over-discharge protection circuit 21 is enabled, detecting the power supply voltage, comparing the power supply voltage with the first voltage threshold value to judge whether the battery is over-discharged, and when the power supply voltage is smaller than the first voltage threshold value, considering that the battery is over-discharged, generating a detection turning signal and sending the detection turning signal to the delay circuit 40.
When the overcharge protection circuit 22 is enabled, detecting the power supply voltage, comparing the power supply voltage with the second voltage threshold to judge whether the battery is overcharged, and when the power supply voltage is greater than the second voltage threshold, considering that the battery is overdischarged, generating a detection turning signal and sending the detection turning signal to the delay circuit 40.
Optionally, as a preferred example of the present invention, as shown in fig. 6, the current protection circuit 30 includes a discharge overcurrent protection circuit 31, a short-circuit protection circuit 32, and a charge overcurrent protection circuit 33;
the first ends of the discharging overcurrent protection circuit 31, the short-circuit protection circuit 32 and the charging overcurrent protection circuit 33 are respectively connected with the loop current sampling points;
second ends of the discharging overcurrent protection circuit 31, the short-circuit protection circuit 32 and the charging overcurrent protection circuit 33 are respectively connected with the delay circuit 40;
the discharging overcurrent protection circuit 31 is configured to obtain a discharging current from the loop current sampling point, and send a detection turning signal to the delay circuit 40 when the discharging current is greater than a first current threshold; the charging overcurrent protection circuit 33 is configured to obtain a charging current from the loop current sampling point, and send a detection turning signal to the delay circuit 40 when the charging current is greater than a second current threshold; the short-circuit protection circuit 32 is configured to obtain a short-circuit voltage from the loop current sampling point, and send a detection flip signal to the delay circuit 40 when the short-circuit voltage is greater than a short-circuit protection voltage threshold.
Here, the first current threshold is a discharge protection current threshold, and is a criterion for determining whether the loop current is too large during the discharge of the battery. The second current threshold is a charging protection current threshold, and is a standard for judging whether the loop current is too large in the battery charging process. The short-circuit protection voltage threshold is a standard for judging whether a short circuit occurs in the charging and discharging process of the battery.
When the discharge overcurrent protection circuit 31 is enabled, a loop current is detected. In practical application, the first current threshold may be converted into a first protection voltage, then a voltage value of a loop current sampling point VM is obtained through a current detection resistor, the voltage value is compared with the first protection voltage, if the voltage value is greater than the first protection voltage, the loop current is considered to be greater than the first current threshold, and if the loop current is too large in the battery discharge process, a detection turning signal is generated and sent to the delay circuit 40.
When the charging overcurrent protection circuit 33 is enabled, a loop current is detected. In practical application, the second current threshold may be converted into a second protection voltage, then the voltage value of the loop current sampling point VM is obtained through the current detection resistor, the voltage value is compared with the second protection voltage, if the voltage value is smaller than the second protection voltage, the loop current is considered to be larger than the second current threshold, and if the loop current is too large in the battery charging process, a detection turning signal is generated and sent to the delay circuit 40.
When the short-circuit protection circuit 32 is enabled, it is detected whether the battery is short-circuited. In practical application, a short-circuit protection voltage threshold is preset, a voltage value of a loop current sampling point VM is obtained, the voltage value is compared with the short-circuit protection voltage threshold, if the voltage value is smaller than the short-circuit protection voltage threshold, a battery is considered to be short-circuited, a detection turning signal is generated and sent to the delay circuit 40.
The above-mentioned embodiments are only used for illustrating the technical solution of the present invention, and not for limiting the same; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not substantially depart from the spirit and scope of the embodiments of the present invention, and are intended to be included within the scope of the present invention.
Claims (10)
1. A battery protection circuit, comprising:
the circuit comprises a reference and bias circuit, a voltage protection circuit, a current protection circuit, a delay circuit, a switching tube control circuit, a switching tube and a clamping circuit;
the first end of the voltage protection circuit is connected with a power supply voltage sampling point, and the second end of the voltage protection circuit is connected with the first end of the delay circuit;
the first end of the current protection circuit is connected with the loop current sampling point, and the second end of the current protection circuit is connected with the second end of the delay circuit;
the second end of the delay circuit is connected with the first end of the switch tube control circuit;
the second end of the switch tube control circuit is connected with the grid electrode of the switch tube;
the source electrode and the drain electrode of the switching tube are connected in series in a charge-discharge loop between the battery and a charging power supply or a load;
the first end of the clamping circuit is connected with the power supply voltage sampling point, the second end of the clamping circuit is connected with the negative electrode of the battery in common, and the third end of the clamping circuit is connected with the loop current sampling point;
the loop current sampling point is positioned at the negative pole of the charging power supply or the load side;
the reference and bias circuit is connected with the power supply voltage sampling point;
the reference and bias circuit is used for generating bias voltage required by the voltage protection circuit and bias current required by the current protection circuit; the voltage protection circuit is used for detecting power supply voltage and generating a detection turning signal when the power supply voltage is abnormal; the current protection circuit is used for detecting the charging current and the discharging current and generating a detection turnover signal when the charging current and the discharging current are abnormal; the delay circuit is used for carrying out delay processing on the detection overturning signal; the switch tube control circuit is used for generating a control signal according to an output signal of the delay circuit and sending the control signal to the switch tube so as to control the switch tube to be started or closed; the clamping circuit is used for clamping the loop current sampling point when the negative high voltage appears at the loop current sampling point.
2. The battery protection circuit of claim 1, wherein when the clamp circuit is in operation, a voltage drop between the second terminal and the third terminal is less than a source-drain breakdown voltage of the switching tube.
3. The battery protection circuit of claim 2, wherein the clamping circuit comprises an NMOS transistor and a diode string, the diode string comprising a plurality of diodes connected in series;
the drain electrode of the NMOS tube is connected with the power supply voltage sampling point, the grid electrode of the NMOS tube is connected with the negative electrode of the battery in common, and the source electrode of the NMOS tube is connected with the positive electrode of the diode string;
and the cathode of the diode string is connected with the loop current sampling point.
4. The battery protection circuit of claim 3, wherein a sum of a threshold voltage of the NMOS transistor and a turn-on voltage of the plurality of diodes is less than a source-drain breakdown voltage of the switch transistor.
5. The battery protection circuit of claim 2, wherein the clamp circuit comprises an NMOS string, the NMOS string comprising a plurality of NMOS transistors connected in series;
the source electrode of each NMOS tube is connected with a common contact between the drain electrode and the grid electrode of the next NMOS tube;
the drain electrode of the first NMOS tube is connected with the power supply voltage sampling point, and the grid electrode and the negative electrode of the battery are connected to the ground in common;
and the source electrode of the last NMOS tube is connected with the loop current sampling point.
6. The battery protection circuit of claim 5, wherein the sum of the threshold voltages of the plurality of NMOS transistors is less than the source-drain breakdown voltage of the switch transistor.
7. The battery protection circuit of claim 2, wherein the clamp circuit comprises an NMOS transistor and a PMOS transistor string, the PMOS transistor string comprising a plurality of PMOS transistors connected in series;
the drain electrode of the NMOS tube is connected with the power supply voltage sampling point, the grid electrode of the NMOS tube is connected with the negative electrode of the battery in common, and the source electrode of the NMOS tube is connected with the source electrode of the first PMOS tube in the PMOS tube string;
in the PMOS tube string group, a common contact between the grid electrode and the drain electrode of each PMOS tube is connected with the source electrode of the next PMOS tube, and a common contact between the grid electrode and the drain electrode of the last PMOS tube is connected with the loop current sampling point.
8. The battery protection circuit of claim 7, wherein a sum of a threshold voltage of the NMOS transistor and a threshold voltage of the PMOS transistors is less than a source-drain breakdown voltage of the switch transistor.
9. The battery protection circuit according to any one of claims 1 to 8, wherein the switching tube control circuit comprises a logic circuit, a substrate switching circuit, a gate control circuit;
the input end of the logic circuit is connected with the second end of the delay circuit, the first output end of the logic circuit is connected with the first end of the substrate switching circuit, and the second output end of the logic circuit is connected with the first end of the grid control circuit;
the second end of the substrate switching circuit is connected with the substrate of the switch tube;
the output end of the grid control circuit is connected with the grid of the switching tube;
the logic circuit is used for carrying out logic processing on an output signal of the delay circuit, generating a substrate switching signal, sending the substrate switching signal to the substrate switching circuit, generating a control signal and sending the control signal to the grid control circuit; the substrate switching circuit is used for switching the substrate polarity of the switching tube according to the substrate switching signal; the grid control circuit is used for outputting a grid control signal to the switching tube according to the control signal so as to control the grid of the switching tube to be started or closed.
10. The battery protection circuit of any of claims 1 to 8, wherein the switching tube is an isolated MOSFET or a non-isolated MOSFET.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202022087473.3U CN213402499U (en) | 2020-09-21 | 2020-09-21 | Battery protection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202022087473.3U CN213402499U (en) | 2020-09-21 | 2020-09-21 | Battery protection circuit |
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| CN213402499U true CN213402499U (en) | 2021-06-08 |
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| CN202022087473.3U Active CN213402499U (en) | 2020-09-21 | 2020-09-21 | Battery protection circuit |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113437064A (en) * | 2021-07-20 | 2021-09-24 | 上海华虹宏力半导体制造有限公司 | Voltage protection circuit |
| CN113872266A (en) * | 2021-08-27 | 2021-12-31 | 深圳市创芯微微电子有限公司 | Battery protection circuit, battery protection chip and battery system |
| CN116799766A (en) * | 2023-08-24 | 2023-09-22 | 禹创半导体(深圳)有限公司 | Protection circuit for detecting load during cascade application of battery protection chips |
-
2020
- 2020-09-21 CN CN202022087473.3U patent/CN213402499U/en active Active
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113437064A (en) * | 2021-07-20 | 2021-09-24 | 上海华虹宏力半导体制造有限公司 | Voltage protection circuit |
| CN113437064B (en) * | 2021-07-20 | 2023-08-18 | 上海华虹宏力半导体制造有限公司 | Voltage protection circuit |
| CN113872266A (en) * | 2021-08-27 | 2021-12-31 | 深圳市创芯微微电子有限公司 | Battery protection circuit, battery protection chip and battery system |
| CN113872266B (en) * | 2021-08-27 | 2023-03-24 | 深圳市创芯微微电子有限公司 | Battery protection circuit, battery protection chip and battery system |
| CN116799766A (en) * | 2023-08-24 | 2023-09-22 | 禹创半导体(深圳)有限公司 | Protection circuit for detecting load during cascade application of battery protection chips |
| CN116799766B (en) * | 2023-08-24 | 2023-12-12 | 禹创半导体(深圳)有限公司 | Protection circuit for detecting load during cascade application of battery protection chips |
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Address after: Building 3A28, Smart Home Phase II, No. 76 Baohe Avenue, Baolong Community, Baolong Street, Longgang District, Shenzhen City, Guangdong Province, 518000 Patentee after: Shenzhen Chuangxin Microelectronics Co.,Ltd. Address before: 518116 Room 401, block a, Longgang smart home, 76 Baohe Avenue, Baolong community, Baolong street, Longgang District, Shenzhen City, Guangdong Province Patentee before: SHENZHEN CHUANGXINWEI MICROELECTRONICS Co.,Ltd. |