Drive circuit for a protection switch applied to a battery module

Abstract

The application discloses a driving circuit applied to a protection switch of a battery module, which comprises a reverse switch, a non-reverse switch, a capacitor and an energy accumulator; a pulse width modulation signal is used to control the on or off of the reverse switch and the non-reverse switch; when the pulse width modulation signal is at a high level, the reverse switch is off and the non-reverse switch is on, the total voltage of the battery charges the first capacitor and a storage voltage is formed on the capacitor; when the pulse width modulation signal is at a low level, the reverse switch is on and the non-reverse switch is off, a reference voltage is connected to the capacitor through the reverse switch, so that a boosted voltage formed by the superposition of the reference voltage and the storage voltage is formed on the energy accumulator; then, the boosted voltage drives the protection switch to be on.

Description

Technical Field

[0001] This invention relates to a drive circuit, and more particularly to a drive circuit for use in a protective switch of a battery module. Background Technology

[0002] With the evolution of technology, various electronic devices have gradually become indispensable tools in people's lives. To facilitate the use of electronic devices anytime and anywhere, many electronic devices typically have a battery module inside. Electronic devices operate by the energy provided by the battery module.

[0003] For safety reasons, a protection switch is usually installed on the high side (e.g., the positive terminal) of the battery module to electrically connect to the applied electronic devices. When the battery module malfunctions (e.g., overcurrent) or is used improperly (e.g., incorrect battery polarity), the power is cut off by controlling the protection switch, which prevents the battery module from continuing to charge or discharge under these circumstances, thus avoiding damage to the battery module.

[0004] The battery module uses MOS field-effect transistors (such as NMOS field-effect transistors) as protection switches. Traditionally, integrated circuits (such as driver ICs) are used to drive these protection switches. The integrated IC applies a control signal greater than the total battery voltage of the battery module to the gate of the protection switch, thereby turning on the protection switch and allowing the battery module to charge and discharge.

[0005] Integrated circuits (ICs) typically provide only a fixed drive current. If an IC needs to drive multiple parallel protection switches simultaneously, its driving capability becomes significantly insufficient. Furthermore, to extend the power supply time of battery modules, the number of battery cells inside is increasing, resulting in commercially available battery modules often having a total battery voltage exceeding 100V. However, due to the characteristics of semiconductor materials, the drive voltage of an IC has a voltage limit that is difficult to overcome, such as 75V. Therefore, the drive voltage of the IC is often lower than the total battery voltage of the battery module, making it unable to drive the battery module's protection switches. Summary of the Invention

[0006] Based on the technical problems in the prior art, the present invention proposes a driving circuit, which is applied to the protection switch on the high side of a battery module and includes a reverse switch, a non-reverse switch, a capacitor, an energy storage device, and a driving switch. When the driving circuit operates, it uses a pulse width modulation signal to control the conduction or deactivation of the reverse switch and the non-reverse switch to execute the charging procedure of the capacitor or to execute the superposition of the reference voltage and the stored voltage of the capacitor. When the voltage superimposed by the reference voltage and the stored voltage of the capacitor is greater than the total battery voltage of the battery module, a boost voltage higher than the total battery voltage is obtained on the energy storage device. Then, when the capacitor is further charged so that its stored voltage is equal to the total battery voltage, a final boost voltage superimposed by the total battery voltage and the reference voltage is obtained on the energy storage device. This final boost voltage will be higher than the sum of the total battery voltage and the threshold voltage of the protection switch. Then, the final boost voltage can become the gate driving voltage to drive the protection switch to conduct.

[0007] This invention proposes a driving circuit in which a reference voltage higher than the threshold voltage of the protection switch is superimposed on the total battery voltage of the battery module. This ensures that the superimposed boost voltage is always higher than the sum of the total battery voltage and the threshold voltage of the protection switch. Thus, even if the battery module is an ultra-high voltage battery module, the driving circuit can provide an ultra-high voltage gate driving voltage in a timely manner to drive the protection switch to turn on.

[0008] To achieve the above objectives, this invention proposes a drive circuit for a protection switch of a battery module. The battery module is connected to the protection switch, and the battery module charges or discharges when the protection switch is turned on. The drive circuit includes: a reverse switch; a non-reverse switch, a pulse width modulation signal used to control the on / off state of the reverse switch and the non-reverse switch; a first capacitor, one end of which is connected to a first node along with the reverse switch and the non-reverse switch, and the other end of which is connected to a second node; a first diode, the anode of which is connected to the total battery voltage of the battery module, and the cathode of which is connected to the second node; a second diode, the anode of which is connected to the second node, and the cathode of which is connected to a third node; an energy storage device, one end of which is connected to the third node, and the other end of which is connected to the total battery voltage; and a drive switch, which is a transistor switch, the first end of which is connected to the protection switch, and the second end of which is connected to the third node. The control terminal is connected to the total battery voltage. When the pulse width modulation signal is high, the reverse switch is closed and the non-reverse switch is on, and the total battery voltage charges the first capacitor to form a storage voltage on the first capacitor. When the pulse width modulation signal is low, the reverse switch is on and the non-reverse switch is closed, and the reference voltage is connected to the first node through the reverse switch to form a superimposed voltage of the reference voltage and the storage voltage on the second node. When the superimposed voltage is higher than the total battery voltage, a boost voltage higher than the total battery voltage will be formed on the energy storage device. When the first capacitor is charged so that the storage voltage is equal to the total battery voltage, a final boost voltage of the total battery voltage and the reference voltage will be formed on the energy storage device. When the drive switch is on, the final boost voltage drives the protection switch to turn on through the drive switch.

[0009] Preferably, the protection switch is an N-channel field-effect transistor located on the high side of the battery module.

[0010] Preferably, the driving switch is a P-channel field-effect transistor or a PNP transistor.

[0011] Preferably, the final boost voltage is higher than the sum of the total battery voltage and the threshold voltage of the protection switch.

[0012] Preferably, the drive switch will turn on when the voltage difference between the final boost voltage and the total battery voltage is greater than the threshold voltage of the drive switch.

[0013] Preferably, the reverse switch includes a first switch, a second switch, and a third switch, all of which are transistor switches. The first terminal of the first switch is connected to a reference voltage, the second terminal is grounded, and the control terminal receives a pulse width modulation signal. The first terminal of the second switch is grounded, the second terminal is connected to the reference voltage, and the control terminal is connected to the first terminal of the first switch. The first terminal of the third switch is connected to a first node, the second terminal is connected to the reference voltage, and the control terminal is connected to the first terminal of the second switch. When the pulse width modulation signal is at a high level, the first switch is on, the second switch is on, and the third switch is off. When the pulse width modulation signal is at a low level, the first switch is off, the second switch is off, and the third switch is on.

[0014] Preferably, the first switch is an N-channel field-effect transistor or an NPN transistor, while the second and third switches are P-channel field-effect transistors or PNP transistors, respectively.

[0015] Preferably, the non-reverse switch is a transistor switch, with its first terminal connected to the first node, its second terminal grounded, and its control terminal receiving a pulse width modulation signal. When the pulse width modulation signal is at a high level, the non-reverse switch is turned on; when the pulse width modulation signal is at a low level, the non-reverse switch is turned off.

[0016] Preferably, the non-reverse switch is an N-channel field-effect transistor or an NPN transistor.

[0017] Furthermore, the drive circuit applied to the protection switch of the battery module also includes a voltage regulator, which is connected to the total battery voltage and uses the total battery voltage to adjust a reference voltage. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the driving circuit of the present invention operating when the pulse width modulation signal is at a high level.

[0019] Figure 2 This is a schematic diagram of the driving circuit of the present invention operating when the pulse width modulation signal is at a low level.

[0020] Explanation of reference numerals in the attached figures:

[0021] 100: Battery Module

[0022] 101: Positive Input / Output

[0023] 102: Negative Input / Output

[0024] 11: Battery Cell

[0025] 13: Protective switch

[0026] 200: Drive circuit

[0027] 201: Pulse Width Modulation Signal

[0028] 21: Reverse switch

[0029] 211: First Switch

[0030] 212: Second Switch

[0031] 213: Third Switch

[0032] 22: Non-reverse switch

[0033] 23: First capacitor

[0034] 24: First Diode

[0035] 25: Second diode

[0036] 26: Energy Storage Device

[0037] 27: Drive switch

[0038] 281: First Node

[0039] 282: Second Node

[0040] 283: Third Node

[0041] 29: Voltage Regulator

[0042] R1: First resistor

[0043] R2: Second resistor

[0044] R3: Third resistor

[0045] R4: Fourth resistor

[0046] R5: Fifth resistor

[0047] R6: Sixth resistor

[0048] R7: Seventh resistor

[0049] R8: Eighth resistor Detailed Implementation

[0050] Please see Figure 1 and Figure 2 These are schematic diagrams of the driving circuit of the present invention operating when the pulse-width modulation (PWM) signal is at a high level and when the driving circuit of the present invention is at a low level. The driving circuit of the present invention is applied to a battery module to control the switching of the battery module's protection switch. Firstly, as... Figure 1As shown, the battery module 100 includes a plurality of battery cells 11 connected in series. These battery cells 11 connected in series form a total battery voltage V. BAT The positive terminal of battery module 100 is connected to positive input / output (Input+ / Output+) 101, and the negative terminal is connected to negative input / output (Input- / Output-) 102. A protection switch 13 is located on the high side of battery module 100, such as between positive input / output (Input+ / Output+) 101 and the positive terminal of battery module 100. In this invention, the protection switch 13 is a transistor switch, such as an N-channel field-effect transistor (e.g., an NMOS field-effect transistor).

[0051] The drive circuit 200 includes a reverse switch 21, a non-reverse switch 22, a first capacitor 23, a first diode 24, a second diode 25, an energy storage device 26, and a drive switch 27. The drive circuit 200 receives a pulse width modulation (PWM) signal 201 and uses the PWM signal 201 to control the on / off state of the reverse switch 21 and the non-reverse switch 22. The PWM signal 201 can be generated by a battery management system (BMS) or a battery management chip. When the PWM signal 201 is high, the reverse switch 21 is off, and the non-reverse switch 22 is on. When the PWM signal 201 is low, the reverse switch 21 is on, and the non-reverse switch 22 is off.

[0052] Furthermore, the reverse switch 21 includes a first switch 211, a second switch 212, and a third switch 213. The first switch 211, the second switch 212, and the third switch 213 are all transistor switches. The first switch 211 can also be an N-channel field-effect transistor or an NPN transistor, while the second switch 212 and the third switch 213 can also be P-channel field-effect transistors (such as PMOS field-effect transistors) or PNP transistors. The first terminal (drain or collector) of the first switch 211 is connected to the reference voltage V. REF The second terminal (source or emitter) is grounded, while the control terminal (gate or base) receives the pulse width modulation signal 201 through the first resistor R1. The first terminal (drain or collector) of the second switch 212 is grounded through the second resistor R2, and the second terminal (source or emitter) is connected to the reference voltage V. REF The control terminal (gate or base) is connected to the first terminal of the first switch 211 via the third resistor R3 and to the second terminal of the second switch 212 via the fourth resistor R4. The first terminal (drain or collector) of the third switch 213 is connected to the first node 281 via the fifth resistor R5, and the second terminal (source or emitter) is connected to the reference voltage V via the sixth resistor R6. REF The control terminal (gate or base) is connected to the first terminal of the second switch 212.

[0053] Additionally, the non-reverse switch 22 is a single-transistor switch, which can also be an N-channel field-effect transistor or an NPN transistor. The first terminal (drain or collector) of the non-reverse switch 22 is connected to the first node 281 through the seventh resistor R7, the second terminal (source or emitter) is grounded, and the control terminal (gate or base) receives the pulse width modulation signal 210 through the eighth resistor R8.

[0054] One end of the first capacitor 23 is connected to the first node 281 along with the reverse switch 21 and the non-reverse switch 22, while the other end is connected to the second node 282. The positive terminal of the first diode 24 is connected to the total battery voltage V of the battery module 100. BAT The negative terminal is connected to the second node 282. The positive terminal of the second diode 25 is connected to the second node 282, while the negative terminal is connected to the third node 283. The energy storage device 26 consists of at least a capacitor, one end of which is connected to the third node 283 and the other end is connected to the total battery voltage V. BAT The drive switch 27 is also a transistor switch, such as a P-channel field-effect transistor or a PNP transistor. Its first terminal (drain or collector) is connected to the protection switch 13, its second terminal (source or emitter) is connected to the third node 283, and its control terminal (gate or base) is connected to the total battery voltage V. BAT In addition, the drive circuit 200 also includes a voltage regulator 29, such as a voltage converter, which is connected to the battery module 100 (not shown) to utilize the total battery voltage V of the battery module 100. BAT Adjust the reference voltage V REF For example: Voltage regulator 29 adjusts the total battery voltage V above 100V. BAT Adjusted to a reference voltage of 12V V REF In this invention, the reference voltage V REF The threshold voltage V of the protection switch 13 is greater than or equal to TH (e.g. V) GS ).

[0055] Specifically, when the drive circuit 200 is operating, it will receive the pulse width modulation signal 201. For example... Figure 1 As shown, when the pulse width modulation signal 201 is at a high level, the first switch 211 of the reverse switch 21 is turned on, the second switch 212 is turned on, and the third switch 213 is turned off. The non-reverse switch 22 is turned on, and the total battery voltage V BAT The first capacitor 23 is charged to store electricity in the first capacitor 23, thereby forming a storage voltage V. S .like Figure 2 As shown, when the pulse width modulation signal 201 is at a low level, the first switch 211 of the inverting switch 21 is closed, the second switch 212 is closed, and the third switch 213 is turned on, while the non-inverting switch 22 is closed. Therefore, the reference voltage V... REFThe third switch 213 is electrically connected to the first node 281 to form a voltage V stored at the second node 282. S and reference voltage V REF The superimposed voltage V C =V S +V REF .

[0056] Subsequently, the pulse width modulation signal 201 repeatedly switches between high and low levels, and the first capacitor 23 is continuously charged by the total battery voltage V. BAT Charging causes the superimposed voltage V on the second node 282 to... C Higher than the total battery voltage V BAT At that time, a boost voltage V will be generated on the energy storage device 26. B =V S +V REF .

[0057] The pulse width modulation signal 201 continues to repeatedly switch between high and low levels, and the first capacitor 23 continues to be charged by the total battery voltage V. BAT Charging causes the storage voltage V formed on the first capacitor 23 to increase. S Equal to the total battery voltage V BAT Then, the reference voltage V REF Superimposed to the total battery voltage V BAT Storage voltage V S =V BAT Above, so as to form a superimposed voltage V at the second node 282. C =V BAT +V REF And form the final boost voltage V on the energy storage device 26. BF =V BAT +V REF .

[0058] The final boost voltage V BF =V BAT +V REF The final boost voltage V is formed after the energy storage device 26. BF =V BAT +V REF With the total battery voltage V BAT Voltage difference V between d =V REF It will be greater than the threshold voltage V of the drive switch 27. TH (e.g. V) SG This causes the drive switch 27 to be turned on. Then, the final boost voltage V... BF =V BAT +V REFThe gate drive voltage of the protection switch 13 is used to drive the protection switch 13 to conduct through the drive switch 27.

[0059] Therefore, the driving circuit 200 of the present invention uses a pulse width modulation signal 201 to control the switching on or off of switches 21 and 22 to perform the charging of capacitor 23 or the reference voltage V. REF With the storage voltage V of capacitor 23 S The superposition, and at the reference voltage V REF With the storage voltage V of capacitor 23 S The superimposed voltage V c Greater than the total battery voltage V BAT At that time, a voltage higher than the total battery voltage V is obtained at the energy storage device 26. BAT boost voltage V B Next, capacitor 23 is further charged, causing its stored voltage V to increase. S Equivalent to the total battery voltage V BAT At that time, a voltage V from the total battery voltage will be obtained on the energy storage device 26. BAT With reference voltage V REF The final boost voltage V generated by superposition BF This final boost voltage V BF It will be higher than the total battery voltage V. BAT With the threshold voltage V of the protection switch 13 TH The summation of these values ​​results in the final boost voltage V. BF It can become the gate drive voltage to drive the protection switch 13 to conduct.

[0060] Thus implemented, the circuit design of the drive circuit 200 of the present invention is based on the total battery voltage V. BAT On top of this, a voltage V higher than the threshold voltage of the protection switch 13 is further superimposed. TH Reference voltage V REF So that the final boost voltage V is obtained by superposition. BF Always higher than the total battery voltage V BAT With the threshold voltage V of the protection switch 13 TH Therefore, even if the battery module 100 is an ultra-high voltage battery module 100, the drive circuit 200 of the present invention can provide an ultra-high voltage gate drive voltage in a timely manner to drive the protection switch 13 to turn on.

[0061] Furthermore, in a preferred embodiment of the present invention, the first capacitor 23 and the energy storage device 26 may also be selected as large-capacity capacitors as energy storage elements, and the reverse switch 21 and the non-reverse switch 22 may also be selected as transistors with high voltage resistance as switching elements, so that the driving circuit 200 of the present invention can be applied to the driving of the protection switch 13 of the high-voltage battery module 100.

[0062] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection claimed by the present invention. All equivalent variations and modifications made in accordance with the shape, structure, features and spirit described in the claims of the present invention should be included within the scope of the claims of the present invention.

Claims

1. A drive circuit applied to a protection switch of a battery module, wherein the battery module is connected to the protection switch, and the battery module charges or discharges when the protection switch is turned on, characterized in that, The driving circuit includes: Reverse switch; The non-reverse switch is controlled by a pulse width modulation signal to turn the reverse switch and the non-reverse switch on or off. The first capacitor has one end connected to the first node along with the reverse switch and the non-reverse switch, and the other end connected to the second node. The first diode has its positive terminal connected to the total battery voltage of the battery module and its negative terminal connected to the second node; The second diode has its positive terminal connected to the second node and its negative terminal connected to the third node; An energy storage device, one end of which is connected to the third node and the other end of which is connected to the total battery voltage; and The drive switch is a transistor switch, with its first terminal connected to the protection switch, its second terminal connected to the third node, and its control terminal connected to the total battery voltage. Specifically, when the pulse width modulation signal is at a high level, the reverse switch is closed and the non-reverse switch is on, and the total battery voltage charges the first capacitor to form a stored voltage on the first capacitor; when the pulse width modulation signal is at a low level, the reverse switch is on and the non-reverse switch is closed, and the reference voltage is connected to the first node through the reverse switch to form a superimposed voltage of the reference voltage and the stored voltage on the second node. When the superimposed voltage is higher than the total battery voltage, a boost voltage higher than the total battery voltage will be formed on the energy storage device; when the first capacitor is charged so that the stored voltage is equal to the total battery voltage, a final boost voltage of the total battery voltage and the reference voltage will be formed on the energy storage device; when the drive switch is on, the final boost voltage drives the protection switch to be on through the drive switch.

2. The drive circuit applied to the protection switch of the battery module according to claim 1, characterized in that, The protection switch is an N-channel field-effect transistor located on the high side of the battery module.

3. The drive circuit applied to the protection switch of the battery module according to claim 1, characterized in that, The driving switch is a P-channel field-effect transistor or a PNP transistor.

4. The drive circuit applied to the protection switch of the battery module according to claim 1, characterized in that, The final boost voltage is higher than the sum of the total battery voltage and the threshold voltage of the protection switch.

5. The drive circuit applied to the protection switch of the battery module according to claim 1, characterized in that, The drive switch will turn on when the voltage difference between the final boost voltage and the total battery voltage is greater than the threshold voltage of the drive switch.

6. The drive circuit applied to the protection switch of the battery module according to claim 1, characterized in that, The reverse switch includes a first switch, a second switch, and a third switch, all of which are transistor switches. The first switch has a first terminal connected to the reference voltage, a second terminal grounded, and a control terminal receiving the pulse width modulation signal. The second switch has a first terminal grounded, a second terminal connected to the reference voltage, and a control terminal connected to the first terminal of the first switch. The third switch has a first terminal connected to the first node, a second terminal connected to the reference voltage, and a control terminal connected to the first terminal of the second switch. When the pulse width modulation signal is at a high level, the first switch is on, the second switch is on, and the third switch is off. When the pulse width modulation signal is at a low level, the first switch is off, the second switch is off, and the third switch is on.

7. The drive circuit for a protection switch applied to a battery module according to claim 6, characterized in that, The first switch is an N-channel field-effect transistor or an NPN transistor, while the second switch and the third switch are respectively a P-channel field-effect transistor or a PNP transistor.

8. The drive circuit for a protection switch applied to a battery module according to claim 1, characterized in that, The non-reverse switch is the transistor switch. The first terminal of the non-reverse switch is connected to the first node, the second terminal is grounded, and the control terminal receives the pulse width modulation signal. When the pulse width modulation signal is at the high level, the non-reverse switch is turned on; when the pulse width modulation signal is at the low level, the non-reverse switch is turned off.

9. The drive circuit for a protection switch applied to a battery module according to claim 8, characterized in that, The non-reverse switch is an N-channel field-effect transistor or an NPN transistor.

10. The drive circuit applied to the protection switch of the battery module according to claim 1, characterized in that, It also includes a voltage regulator connected to the total battery voltage and using the total battery voltage to adjust the reference voltage.

Images