Charging control circuit and vehicle

Abstract

The invention discloses a charging control circuit and a vehicle. The charging control circuit comprises a temperature sensor, a voltage adjusting circuit and a charging protection circuit, and the temperature sensor detects the battery temperature of a battery and outputs an output voltage corresponding to the battery temperature; the voltage adjusting circuit is used for adjusting the output voltage of the temperature sensor, so that when the battery temperature of the battery reaches a target temperature threshold value, the voltage input to the charging protection circuit is target voltage, and the target temperature threshold value is the battery temperature enabling the charging protection circuit to control the charger to stop charging the battery. The difference between the target voltage and the power supply voltage of the voltage regulation circuit is greater than a preset voltage value; the charging protection circuit is used for comparing the voltage output by the voltage adjusting circuit with the target voltage and outputting a control signal according to the comparison result so as to control the charger to be turned off or turned on. According to the invention, when the battery is over-temperature, the charger is timely and accurately controlled to stop charging the battery, and the charging safety of the battery is ensured.

Description

Technical Field

[0001] The present application belongs to the field of electronic technology, and in particular, relates to a charging control circuit and a vehicle. Background Art

[0002] Batteries can power various devices or equipment. In order to protect the environment and save resources, batteries are usually used to power devices or equipment in practical applications. During the battery charging process, the battery temperature must be kept within a suitable range. Accidents are prone to occur if the battery temperature is too high or too low.

[0003] To ensure the safety of the battery during charging, the battery temperature is usually collected through an NTC (Negative Temperature Coefficient) sensor or other temperature sensor. The temperature is then calculated by a processor to determine whether the battery temperature is too high, and the charger is turned off when the battery temperature is too high.

[0004] However, when a program running in the processor fails, locks up unexpectedly, or the processor core fails, the processor cannot respond correctly according to the battery temperature, and thus cannot accurately control the charger to shut down in time when the battery overheats. Summary of the invention

[0005] The embodiments of the present application provide a charging control circuit and a vehicle, which can timely and accurately control the charger to stop charging the battery when the battery is overheated, thereby ensuring the charging safety of the battery.

[0006] In a first aspect, an embodiment of the present application provides a charging control circuit, which includes: a temperature sensor, which is used to detect the battery temperature of a battery and output an output voltage corresponding to the battery temperature; a voltage adjustment circuit, wherein the input end of the voltage adjustment circuit is connected to the output end of the temperature sensor, and the output end of the voltage adjustment circuit is connected to the input end of the charging protection circuit, and is used to adjust the output voltage of the temperature sensor so that when the battery temperature of the battery reaches a target temperature threshold, the voltage input to the charging protection circuit is the target voltage, wherein the target temperature threshold is the battery temperature at which the charging protection circuit controls the charger to stop charging the battery, and the difference between the target voltage and the power supply voltage of the voltage adjustment circuit is greater than a preset voltage value; a charging protection circuit, wherein the input end of the charging protection circuit is connected to the output end of the voltage adjustment circuit, and the output end of the charging protection circuit is connected to the charger, and the charging protection circuit is used to compare the voltage output by the voltage adjustment circuit with the target voltage, and output a control signal according to the comparison result to control the charger to shut down or start up.

[0007] In a second aspect, an embodiment of the present application provides a vehicle, which includes a charging control circuit as described in the first aspect.

[0008] This application uses a hardware circuit composed of a temperature sensor, a voltage adjustment circuit, and a charging protection circuit to control the start or shut down of the charger according to the output voltage of the temperature sensor. Since the probability of hardware circuit failure is much lower than the probability of software abnormality, in this application, even if the processor fails and cannot distinguish whether the battery is overheated, it can timely and accurately identify whether the battery is overheated through hardware identification, and then control the charger through hardware when the battery is overheated, so as to reduce the frequency of accidents caused by the battery temperature being too high but continuing to power the battery.

[0009] In addition, in the present application, a voltage adjustment circuit is also provided to adjust the output voltage of the temperature sensor, and then adjust the voltage of the over-temperature comparison point of the charging protection circuit (i.e., the target voltage), so that when the charging protection circuit detects that the voltage value corresponding to the battery temperature reaches the target voltage, the charger is controlled to be turned off. Since the difference between the target voltage and the supply voltage of the voltage adjustment circuit is greater than the preset voltage value, even if the charging control circuit is disturbed by the environment and the input voltage of the charging protection circuit fluctuates, the charging control circuit can accurately control the charger, thereby ensuring the reliability and stability of the charging control circuit, avoiding false triggering caused by voltage fluctuations, and then when the battery is over-temperature, the charger can be started or shut down in a timely and accurate manner through hardware control. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] In order to more clearly illustrate the technical solution of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0011] Figure 1 is a control principle block diagram of a charging control circuit provided by an embodiment of the present application;

[0012] Figure 2 is a schematic diagram of a circuit structure of a battery side provided by an embodiment of the present application;

[0013] Figure 3 is a principle block diagram of a charging control circuit provided by an embodiment of the present application;

[0014] Figure 4 is a schematic circuit diagram of a charging protection circuit provided by an embodiment of the present application;

[0015] Figure 5 is a characteristic diagram of an NTC provided by an embodiment of the present application;

[0016] Figure 6is a circuit structure diagram of a charging control circuit provided by an embodiment of the present application;

[0017] Figure 7 is a schematic diagram of an equivalent circuit structure of a first filter circuit provided by an embodiment of the present application;

[0018] Figure 8 It is a schematic diagram of the structure of a vehicle provided in another embodiment of the present application.

[0019] The reference numerals in the specific implementation manner are as follows:

[0020] 10. Battery side; 20. Charger side;

[0021] 101. Temperature sensor; 102. Battery;

[0022] 201, voltage adjustment circuit; 202, charging protection circuit; 203, charger; 2010, first filter circuit; 2011, hysteresis circuit; 204, digital-to-analog conversion circuit; 205, enabling circuit;

[0023] GND, ground wire; Vbat, positive output terminal of the battery; Vntc, voltage output terminal of the temperature sensor; Vadc, signal output terminal of the analog-to-digital conversion circuit; Vn, signal output terminal of the first filter circuit; Vs, power supply;

[0024] U1, comparator; U2, voltage follower; U3, amplifier; M1, switch component; 2021, drive circuit; 2022, pull-up circuit; Rth, target resistance; Ven, signal output terminal; Vctl, control signal input terminal; R11, first pull-up resistor; R21, second pull-up resistor; R12, first resistor; R22, second resistor; R13, third resistor; R23, fourth resistor; R3, fifth resistor; R4, first drive resistor; R5, second drive resistor; R6, sixth resistor; R7, seventh resistor; R8, eighth resistor; R9, ninth resistor; C1, first capacitor; C2, second capacitor;

[0025] Tprot, temperature value of over-temperature protection point; Rntc, resistance value of temperature sensor. DETAILED DESCRIPTION

[0026] The features and exemplary embodiments of various aspects of the present application will be described in detail below. In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain the present application, rather than to limit the present application. For those skilled in the art, the present application can be implemented without the need for some of these specific details. The following description of the embodiments is only to provide a better understanding of the present application by illustrating the examples of the present application.

[0027] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the statement "include..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0028] It should be noted that the directions or positional relationships indicated by the terms "upper", "lower", "front", "rear", etc. are based on the directions or positional relationships shown in the drawings and are only for the convenience of description. They do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as limitations on this patent.

[0029] It should also be noted that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0030] Before describing the charging control circuit provided in the present application, the control principle of the charging control circuit provided in the present application is first explained.

[0031] In one example, Figure 1 The control principle block diagram of the charging control circuit is shown. Figure 1It can be seen that the control principle block diagram at least includes a temperature sensor 101 and a battery 102 deployed on the battery side 10, and a charging protection circuit 202 and a charger 203 deployed on the charger side 20. The temperature sensor 101 may be a two-terminal element, including but not limited to a thermistor. For example, the temperature sensor 101 may be a negative temperature coefficient thermistor NTC, wherein the thermistor NTC has different resistance values ​​at different temperatures. For example, at 30°C, the resistance value of the NTC is 8.3kΩ; at 125°C, the resistance value of the NTC is 0.5kΩ; at 60°C, the resistance value of the NTC is 3kΩ; at -40°C, the resistance value of the NTC is 200kΩ.

[0032] As an example, Figure 2 FIG. 1 shows a connection circuit diagram between the temperature sensor 101 in the battery side 10 and the battery 102. Figure 2 It can be seen that the negative electrode of the battery 102 is connected to one end of the temperature sensor 101, and then connected to the ground line GND; the positive output end of the battery 102 is Vbat, and the other voltage output end of the temperature sensor 101 is Vntc.

[0033] Structurally, the temperature sensor 101 is usually in close contact with the surface of the battery 102 . Therefore, in practical applications, the temperature detected by the temperature sensor 101 is usually used as the battery temperature of the battery 102 .

[0034] Depend on Figure 1 It can be seen that the temperature sensor 101 detects the battery temperature of the battery 102 and transmits the collected battery temperature to the charging protection circuit 202 of the charger side 20. The charging protection circuit 202 compares the battery temperature with a preset temperature threshold to determine whether the battery 102 is overheated. When the charging protection circuit 202 detects that the battery 102 is overheated, the charging protection circuit 202 sends a control signal to the charger 203 to control the charger 203 to stop charging the battery 102, thereby ensuring the charging safety of the battery.

[0035] As can be seen from the above content, the charger 203 can be started or shut down by the charging protection circuit 202, that is, the charger can be controlled by hardware. Since the probability of hardware circuit failure is much smaller than the probability of software abnormality, in the present application, even if the processor fails and cannot distinguish whether the battery is overheated, it can timely and accurately identify whether the battery is overheated through hardware identification, and then control the charger through hardware when the battery is overheated, so as to reduce the frequency of accidents caused by the battery temperature being too high but continuing to power the battery.

[0036] In order to improve the control accuracy of the charger and ensure the charging safety of the battery, this application is Figure 1Based on the control principle block diagram of the charging control circuit shown in FIG. 1 , the circuit of the charger side 10 is further improved to obtain Figure 3 The functional block diagram of the charging control circuit is shown.

[0037] Depend on Figure 3 It can be seen that the charging control circuit includes a temperature sensor 101 , a battery 102 , a voltage regulating circuit 201 , a charging protection circuit 202 and a charger 203 .

[0038] The temperature sensor 101 is used to detect the battery temperature of the battery 102 and output an output voltage corresponding to the battery temperature. That is, in this application, the output voltage of the temperature sensor 101 represents the battery temperature of the battery 102 .

[0039] In one example, if Figure 3 As shown, the charging protection circuit 202 is connected to the voltage regulating circuit 201 and the charger 203 , wherein the input end of the charging protection circuit 202 is connected to the output end of the voltage regulating circuit 201 , and the output end of the charging protection circuit 202 is connected to the charger 203 .

[0040] Specifically, the charging protection circuit 202 is used to compare the voltage output by the voltage adjustment circuit 201 with the target voltage, and output a control signal according to the comparison result to control the charger 203 to be turned off or started, so that when the control signal is a signal to turn off the charger, the charger 203 connected to the charging protection circuit 202 no longer charges the battery 102; and when the control signal is a signal to start the charger, the charger 203 charges the battery 102.

[0041] The above-mentioned target voltage is the voltage input to the charging protection circuit 202 when the battery temperature of the battery 102 reaches the target temperature threshold, wherein the target temperature threshold is the battery temperature at which the charging protection circuit 202 controls the charger 203 to stop charging the battery 102. For example, when the temperature sensor 101 detects that the battery temperature of the battery 102 is 60°C, the charging protection circuit 202 controls the charger 203 to shut down to stop charging the battery 102. In this scenario, the target temperature threshold is 60°C, at which temperature, the voltage obtained by adjusting the output voltage corresponding to the temperature sensor 101 by the voltage adjustment circuit 201 is the above-mentioned target voltage.

[0042] In one example, Figure 4 The circuit diagram of the charging protection circuit 202 is shown. Figure 4 It can be seen that the charging protection circuit is composed of a comparator U1, a switch component M1, a driving circuit 2021, a pull-up circuit 2022 and a target resistor Rth.

[0043] Depend on Figure 4It can be seen that the comparator U1 is connected to the input terminal of the driving circuit 2021, and is used to compare the filtered output voltage with the target voltage, and generate a comparison signal according to the comparison result, and transmit the comparison signal to the driving circuit 2021 to control the opening and closing of the switch component M1.

[0044] The driving circuit 2021 is connected to the first end of the switch component M1, and is used to control the on or off of the switch component M1 according to the comparison signal. Among them, the driving circuit 2021 is composed of a first driving resistor R4 and a second driving resistor R5, the first driving resistor R4 is connected in series between the comparator U1 and the switch component M1, one end of the second driving resistor R5 is connected to the input end of the switch component M1, and the other end of the second driving resistor R5 is connected to the ground line. As an example, in the present application, the resistance value of the first driving resistor R4 can be 1kΩ, and the resistance value of the second driving resistor R5 can be 10kΩ. The resistance value of the first driving resistor R4 and the resistance value of the second driving resistor R5 are only examples. In actual applications, the resistance values ​​of the two driving resistors can be adjusted according to actual needs.

[0045] Depend on Figure 4 It can be seen that the first end of the switch component M1 is connected to the output end of the driving circuit 2021 , the second end of the switch component M1 is connected to the charger 203 , and the control end of the switch component M1 is connected to the ground line.

[0046] As an example, the first level value may be the supply voltage V s , the second level value may be 0. In addition, the above-mentioned switch component M1 may be, but is not limited to, a MOS (Metal-Oxide-Semiconductor) tube. For example, the switch component M1 may be an NMOS (N-Metal-Oxide-Semiconductor) tube, and the switch component M1 may also be a PMOS (P-Metal-Oxide-Semiconductor) tube. In the scenario where the switch component M1 is an NMOS, the first end of the switch component M1 is the gate of the NMOS, the second end of the switch component M1 is the drain of the NMOS, and the control end of the switch component M1 is the source of the NMOS. Among them, the switch component M1 is in an on state when the level value corresponding to the comparison signal is a first level value; the switch component M1 is in an off state when the level value corresponding to the comparison signal is a second level value, wherein the first level value is greater than the second level value. That is, when the output voltage of the driving circuit 2021 is at a high level, the switch component M1 is turned on; when the output voltage of the driving circuit 2021 is at a low level, the switch component M1 is turned off.

[0047] It should be noted that, in actual applications, after the output voltage output by the temperature sensor 101 passes through the comparator U1 and the drive circuit 2021, its voltage amplitude is small, and the corresponding output current is also small. At this time, in the circuit, the resistance and the current interfere with each other. Therefore, if the output voltage of the drive circuit 2021 is directly used to control the charger 203, the charger 203 may be falsely triggered. To avoid the above problems, in the present application, a switch component M1 is added after the drive circuit 2021, which can avoid the mutual interference between the resistance and the current, thereby avoiding the false triggering of the charger 203, and thus ensuring the accuracy of the charger control.

[0048] like Figure 4 As shown, the pull-up circuit 2022 is composed of a first pull-up resistor R11 and a second pull-up resistor R21, and the first pull-up resistor R11 and the second pull-up resistor R21 are respectively connected to the inverting input terminal and the non-inverting input terminal of the comparator U1.

[0049] The target resistor Rth is connected to the second pull-up resistor R21 , wherein the resistance value of the target resistor Rth is the resistance value of the temperature sensor 101 at a temperature threshold corresponding to the target voltage.

[0050] The following combination Figure 4 The charging protection circuit is described in detail.

[0051] exist Figure 4 In the embodiment, the resistance values ​​of the first pull-up resistor R11 and the second pull-up resistor R21 can be the same, for example, the resistance values ​​of the first pull-up resistor R11 and the second pull-up resistor R21 can both be 21 kΩ. The resistance value of the target resistor Rth is the set resistance of the over-temperature protection point, that is, the target voltage required for the comparator U1 to perform voltage comparison can be adjusted by adjusting the resistance value of the target resistor Rth. Figure 4 Vs is the power supply, and its corresponding voltage value is V s is 3.3V; Ven is the signal output terminal of the charging protection circuit 202, which can control the charger 203 to be enabled, wherein, when the signal output terminal Ven outputs a high level, the charger 203 charges the battery 102; when the signal output terminal Ven outputs a low level, the charger 203 is turned off and no longer charges the battery 102.

[0052] Depend on Figure 4 It can be seen that the voltage at the non-inverting input terminal of the comparator U1 can be calculated by the following formula:

[0053]

[0054] In formula (1), V p is the voltage at the non-inverting input of comparator U1.

[0055] The voltage at the inverting input of comparator U1 can be calculated as follows:

[0056]

[0057] In formula (2), V n is the voltage at the inverting input of comparator U1, R ntc is the resistance value of the temperature sensor 101, specifically the resistance value of the thermistor.

[0058] The voltage V between the GS of the switch component M1 gs It can be calculated by the following formula:

[0059]

[0060] In formula (3), V gs is the voltage between the GS of the switch component M1, V o is the output voltage of comparator U1.

[0061] When V p With V n When the following equation is satisfied,

[0062] V p ≥V n (4)

[0063] The output voltage of comparator U1 is V o Close to the power supply voltage Vs, that is

[0064] V o =V s (5)

[0065] At this time, V gs Satisfy the following formula:

[0066]

[0067] When V gs Greater than the on-state voltage threshold V of the switch component M1 gs At (th), the switch component M1 is turned on, the signal output terminal Ven outputs a low level, and the charger 203 is turned off.

[0068] When V p With V n When the following equation is satisfied,

[0069] V p <V n (7)

[0070] The output voltage of comparator U1 is V o is 0, that is

[0071] Vo =0 (8)

[0072] At this time, V gs Satisfy the following formula:

[0073] V gs =0 (9)

[0074] Since V gs is 0, therefore, the switch component M1 is disconnected, the signal output terminal Ven is pulled high by the processor to output a high level, the charger 203 is started, and charges the battery 102 .

[0075] In addition, in the scenario where the temperature sensor 101 is an NTC, as the battery temperature increases, the resistance of the NTC decreases, that is, the characteristic diagram corresponding to the NTC is as follows: Figure 5 shown.

[0076] The temperature value of the over-temperature protection point corresponding to the comparator U1 is T prot When Figure 5 The resistance R of the NTC corresponding to the temperature value can be determined prot Therefore, when the battery temperature is greater than T prot When the NTC resistance is less than R prot ; When the battery temperature is less than T prot When the NTC resistance is greater than R prot .

[0077] From the above description, it can be seen that in order to make the charging protection circuit have an over-temperature protection function, that is, to ensure that the battery temperature is greater than T prot When the charger 203 is turned off, the resistance of the target resistor Rth needs to be T prot The corresponding NTC resistance R prot , where R prot It can be 3kΩ.

[0078] Right now

[0079] R th =R prot (10)

[0080] Then formula (1) becomes the following:

[0081]

[0082] From formula (2) and formula (11), it can be seen that when the battery temperature is less than T prot When the resistance of NTC is greater than R prot , at this time, V p <V n , V gsis 0, the switch component M1 is disconnected, the signal output terminal Ven is pulled high by the processor, and the charger 203 charges the battery 102; when the battery temperature is greater than T prot When the NTC resistance is less than R prot , at this time, V p >V n , V gs Greater than V gs (th), the switch component M1 is turned on, the signal output terminal Ven is pulled low, the charger 203 is turned off, and the battery 102 is no longer charged.

[0083] This completes the explanation of the charging protection circuit 202 .

[0084] In one example, by Figure 3 It can be seen that the charging control circuit further includes a voltage regulating circuit 201 , wherein the input end of the voltage regulating circuit 201 is connected to the output end of the temperature sensor 101 , and the output end of the voltage regulating circuit 201 is connected to the input end of the charging protection circuit 202 .

[0085] Among them, the voltage adjustment circuit 201 is used to adjust the output voltage of the temperature sensor 101 so that when the battery temperature of the battery 102 reaches the target temperature threshold, the voltage input to the charging protection circuit 202 is the target voltage, wherein the target temperature threshold is the battery temperature at which the charging protection circuit 202 controls the charger 203 to stop charging the battery 102, and the difference between the target voltage and the power supply voltage of the voltage adjustment circuit 201 is greater than the preset voltage value.

[0086] In one example, Figure 6 The circuit structure diagram of the charging control circuit is shown (the charger, temperature sensor and battery are not shown). Figure 6 It can be seen that the voltage adjustment circuit 201 is composed of a first resistor R12 and a second resistor R22, wherein the first resistor R12 is connected between the temperature sensor 101 and the first pull-up resistor R11, and is used to adjust the voltage value of the inverting input terminal of the comparator U1; the second resistor R22 is connected between the target resistor Rth and the second pull-up resistor R21, and is used to adjust the voltage value of the non-inverting input terminal of the comparator U1. The resistance values ​​of the first resistor R12 and the second resistor R22 can be the same, for example, R 12 =R 22 =18kΩ.

[0087] It should be noted that the above target voltage can be the power supply voltage V s half of the target voltage, that is, the target voltage can be V s / 2. Therefore, the following equation is satisfied between the second resistor R22 and the second pull-up resistor R21:

[0088] R1=R2+Rprot (12)

[0089] In actual applications, the power supply voltage will jitter. Therefore, if the target voltage is set to V s , when the power supply voltage fluctuates, it may cause the charger 203 to be triggered incorrectly. For example, when the target voltage is V s =3.3V, the input voltage of the comparator U1 is 3.25V. If the power supply voltage fluctuates and the target voltage drops from 3.3V to 3.2V, the comparator U1 determines that the battery 102 is overheated and controls the charger 203 to stop charging the battery 102. To avoid the above problem, in this application, the target voltage is set to V s / 2, which can effectively avoid the problem of charger mis-triggering caused by power supply voltage jitter.

[0090] In one example, Figure 6 The circuit structure of the charging control circuit shown in Figure 4 A first filter circuit 2010 and a hysteresis circuit 2011 are added to the circuit structure of the charging control circuit shown.

[0091] Depend on Figure 6 It can be seen that the first filter circuit 2010 is connected to the output end of the voltage adjustment circuit 201, and is used to filter the adjusted output voltage to obtain the filtered output voltage. The first filter circuit 2010 is composed of a temperature sensor 101, a first resistor R12, a first pull-up resistor R11, a first capacitor C1, and a third resistor R13.

[0092] As an example, in the first filter circuit 2010, the first end of the first resistor R12 is connected to the output end of the temperature sensor 101, the second end of the first resistor R12 is connected to the first end of the first pull-up resistor R11, and the second end of the first pull-up resistor R11 is connected to the power supply; the first capacitor C1 is connected in parallel with the third resistor R13, wherein the first end of the first capacitor C1 is connected to the ground line, the second end of the first capacitor C1 is connected to the first end of the first pull-up resistor R11, the first end of the third resistor R13 is connected to the ground line, the second end of the third resistor R13 is connected to the first end of the first pull-up resistor R11, and the first end of the first pull-up resistor R11 is connected to the inverting input end of the comparator U1. The resistance value of the third resistor R13 can be 200kΩ.

[0093] As an example, the temperature sensor 101 is simplified to obtain Figure 7 The equivalent circuit diagram of the first filter circuit 2010 is shown in FIG. Figure 7 In the figure, Rntc is the equivalent resistance of the temperature sensor 101. The resistance of Rntc can be calculated from R ntcIndicates; Vn is the signal output end of the first filtering circuit 2010.

[0094] The transfer function corresponding to the first filter circuit 2010 is:

[0095]

[0096] The cut-off frequency f1 of the first filter circuit 2010 is:

[0097]

[0098] It can be seen from the above formula (14) that the cut-off frequency of the first filter circuit 2010 has nothing to do with the resistance value of the temperature sensor 101, wherein the range of the cut-off frequency f1 can be 0.1kHz <f1<1kHz。

[0099] In one example, by Figure 6 It can be seen that the hysteresis circuit 2011 is connected to the output end of the first filter circuit 2010, and is used to control the charger 203 to restart according to the filtered output voltage after the charger 203 is shut down due to over-temperature. Figure 6 It can be known that the hysteresis circuit 2011 is composed of a third resistor R13 and a fourth resistor R23, wherein the resistance values ​​of the third resistor R13 and the fourth resistor R23 can be the same, for example, both are 200 kΩ.

[0100] As an example, the first end of the third resistor R13 is connected to the ground line, and the second end of the third resistor R13 is connected to the inverting input terminal of the comparator U1; the first end of the fourth resistor R23 is connected to the non-inverting input terminal of the comparator U1, and the second end of the fourth resistor R23 is connected to the output terminal of the comparator U1.

[0101] It should be noted that in the related art, after the charger is shut down due to the over-high battery temperature, the charger is restarted by manual start-up, which may cause the charger to fail to restart in time, thereby causing the battery to be charged untimely. To solve the above problem, in the present application, a hysteresis circuit 2011 is added, so that after the charger is shut down, if the battery temperature drops to a certain level, the charging control circuit controls the charger to restart.

[0102] In addition, in order to increase the voltage range of the restart voltage set by the charging control circuit to control the charger to restart, thereby avoiding the problem of repeated restart of the charger, in this application, on the basis of setting the hysteresis circuit 2011, the target voltage is set to V s / 2.

[0103] In one example, when the charger 203 is operating normally, the output voltage V o is 0. At this time, the input voltage Vpw It can be expressed by the following formula:

[0104]

[0105] The input voltage V nw It can be expressed by the following formula:

[0106]

[0107] That is, when V pw With V nw When the following equation is satisfied, the over-temperature protection takes effect, that is, the charging control circuit controls the charger 203 to be turned off:

[0108] V pw =V nw (17)

[0109] At this time, the resistance value R corresponding to the temperature sensor 101 is ntc1 It can be expressed by the following formula:

[0110] R ntc1 =R prot (18)

[0111] When the over-temperature protection takes effect, the charging control circuit controls the charger 203 to be turned off. At this time, the output voltage V o V s , the input voltage V pu It can be expressed by the following formula:

[0112]

[0113] The input voltage V nu It can be expressed by the following formula:

[0114]

[0115] After the over-temperature protection occurs, if the temperature of the battery 102 meets certain conditions, the charger 203 starts to charge the battery 102 again. pu With V nu Satisfy the following formula:

[0116] V pu =V nu (twenty one)

[0117] When the charger 203 is restarted, the battery temperature detected by the temperature sensor 101 is Trst. At this time, the resistance value of the temperature sensor 101 is R ntc2 , R ntc2 It can be expressed by the following formula:

[0118]

[0119] It should be noted that R1, R2, and R3 in the above formulas (13)-(22) satisfy formulas (23), (24), and (25) respectively:

[0120] R 11 =R 21 =R1 (23)

[0121] R 12 =R 22 =R2 (24)

[0122] R 13 =R 23 =R3 (25)

[0123] It is easy to notice that in order to ensure that formula (17) holds, that is, R ntc2 >0, it is necessary to ensure that R1 and R3 satisfy the following formula:

[0124]

[0125] By comparing formula (18) and (22), we can see that R ntc1 With R ntc2 Satisfy the following formula:

[0126]

[0127] When the resistance values ​​corresponding to the above resistors are used, R ntc1 =3kΩ, R ntc2 =8.3kΩ, f1=0.78kHz.

[0128] When the temperature sensor 101 is a negative temperature coefficient resistor, T rst With T prot Satisfy the following formula:

[0129] T rst <T prot (28)

[0130] In formula (28), T prot The resistance of the temperature sensor 101 is R prot , the temperature of the battery 102 .

[0131] From the above, we can see that when the battery temperature reaches T prot When the battery temperature drops to T rst In order to prevent the battery 102 from being in a high temperature state for a long time, in this application, T is set rst Much smaller than Tprot , for example, setting T rst Set T to 30°C prot is 60℃.

[0132] In one example, if Figure 6 As shown, the charging control circuit also includes a digital-to-analog conversion circuit 204 and an enabling circuit 205. The analog-to-digital conversion circuit 204 is connected to the output end of the temperature sensor 101, and is used to perform analog-to-digital conversion on the output voltage of the temperature sensor 101 to generate a target output voltage; the enabling circuit 205 is connected to the charger 203 through the fifth resistor R3, and is used to receive a control signal sent by the processor, and control the start or shut down of the charger 203 according to the control signal sent by the processor, wherein the control signal sent by the processor is a signal generated by the processor according to the size of the target output voltage and the target voltage.

[0133] Depend on Figure 6 It can be seen that the enabling circuit 205 is composed of a fifth resistor R3 and a switch component M1. When the charger 203 works normally, if the input signal of the control signal input terminal Vctl is high level, the control switch component M1 is turned off, and the signal output terminal Ven outputs a high level, and the charger 203 works normally; when the battery 102 is overheated, the switch component M1 is turned on, the signal output terminal Ven outputs a low level, and the charger 203 stops working. The control signal input terminal Vctl is connected to the processor and can receive the control signal sent by the processor.

[0134] It is easy to notice that in the present application, the output voltage representing the battery temperature collected by the digital-to-analog conversion circuit can be transmitted to the processor, so that when the over-temperature detection circuit fails, the processor can determine whether the battery is over-temperature based on the target output voltage of the digital-to-analog conversion circuit, and then when the battery is over-temperature, the charger can be started or shut down in a timely and accurate manner through software.

[0135] In one example, if Figure 6 As shown, the analog-to-digital conversion circuit 204 is composed of a sampling circuit, a gain circuit and a second filtering circuit ( Figure 6 The sampling circuit, the gain circuit and the second filtering circuit are not marked in the figure). The sampling circuit is connected to the output end of the temperature sensor 101 and is used to sample the output voltage of the temperature sensor 101; the second filtering circuit is connected to the output end of the sampling circuit and is used to filter the output voltage collected by the sampling circuit to obtain a filtered output voltage; the gain circuit is connected to the output end of the second filtering circuit and is used to amplify the filtered output voltage to obtain a target output voltage.

[0136] The following combination Figure 6 The sampling circuit, the gain circuit and the second filtering circuit are described.

[0137] The sampling circuit is composed of a voltage follower U2. Figure 6 It can be seen that the inverting input terminal of the voltage follower U2 is connected to the output terminal of the voltage follower U2, the non-inverting input terminal of the voltage follower U2 is connected to the temperature sensor 101, and the output terminal of the voltage follower U2 is connected to the input terminal of the second filter circuit.

[0138] The gain circuit is composed of an amplifier U3, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8 and a ninth resistor R9. Figure 6 It can be seen that the sixth resistor R6 is connected between the output end of the voltage follower U2 and the non-inverting input end of the amplifier (U3); the first end of the seventh resistor R7 is connected to the ground line, and the second end of the seventh resistor R7 is connected to the non-inverting input end of the amplifier U3; the first end of the eighth resistor R8 is connected to the ground line, and the second end of the eighth resistor R8 is connected to the inverting input end of the amplifier U3; the first end of the ninth resistor R9 is connected to the inverting input end of the amplifier U3, and the second end of the ninth resistor R9 is connected to the output end of the amplifier U3.

[0139] Among them, the gain G of the gain circuit can be expressed by the following formula:

[0140]

[0141] In formula (29), the sixth resistor R6 can have the same resistance as the seventh resistor R7, that is, R6=200kΩ, R7=200kΩ. In addition, the resistance of the eighth resistor R8 can be 100kΩ, and the resistance of the ninth resistor R9 can be 10kΩ. The gain G determined thereby is 0.55.

[0142] It can be seen from formula (29) that the sixth resistor R6 and the seventh resistor R7 have an attenuation effect, and the eighth resistor R8 and the ninth resistor R9 have an amplification effect.

[0143] In one example, by Figure 6 It can be seen that the second filter circuit is composed of the sixth resistor R6, the seventh resistor R7 and the second capacitor C2, wherein the second capacitor C2 is connected in parallel with the seventh resistor R7. Therefore, the transfer function of the second filter circuit can be determined as follows:

[0144]

[0145] The corresponding cut-off frequency f2 is:

[0146]

[0147] Among them, the frequency range of the cut-off frequency f2 is 0.1 kHz < f2 < 1 kHz. Based on the resistance values of the above-mentioned sixth resistor R6, seventh resistor R7, eighth resistor R8, and ninth resistor R9, f2 = 0.72 kHz can be calculated.

[0148] It can be seen from Figure 6 that the signal output terminal of the analog-to-digital conversion circuit 205 is Vadc. To ensure the output accuracy of the digital-to-analog conversion circuit 205, in this application, the output voltage value V of Vadc adc should be less than V ref , and the maximum value of V adc should be about 90% of V ref . Among them, V ref is the reference voltage, which can be 1.8V.

[0149] V adc can be calculated by the following formula:

[0150]

[0151] It can be seen from formula (32) that the range of V adc is 0.01V < V adc < 1.65V.

[0152] As an example, when the battery temperature reaches 125 °C with the resistance values of each resistor determined, V adc = 0.02V; when the temperature sensor is disconnected, V adc = 1.64V.

[0153] It can be seen from the above that in this application, the hardware circuit composed of a temperature sensor, a voltage adjustment circuit, and a charging protection circuit is used to control the start or shutdown of the charger according to the output voltage of the temperature sensor. Since the probability of a hardware circuit failure is much smaller than the probability of a software anomaly, in this application, even when the processor fails and cannot distinguish whether the battery is overheated, the battery can be accurately identified as overheated in a timely manner through hardware recognition, and then the charger can be controlled in a hardware manner when the battery is overheated to reduce the frequency of accidents caused by continuing to supply power to the battery when the battery temperature is too high.

[0154] In addition, in the present application, a voltage adjustment circuit is also provided to adjust the output voltage of the temperature sensor, and then adjust the voltage of the over-temperature comparison point of the charging protection circuit (i.e., the target voltage), so that when the charging protection circuit detects that the voltage value corresponding to the battery temperature reaches the target voltage, the charger is controlled to be turned off. Since the difference between the target voltage and the supply voltage of the voltage adjustment circuit is greater than the preset voltage value, even if the charging control circuit is disturbed by the environment and the input voltage of the charging protection circuit fluctuates, the charging control circuit can accurately control the charger, thereby ensuring the reliability and stability of the charging control circuit, avoiding false triggering caused by voltage fluctuations, and then when the battery is over-temperature, the charger can be started or shut down in a timely and accurate manner through hardware control.

[0155] The present application also provides a vehicle, such as Figure 8 As shown, the vehicle includes the above-mentioned charging control circuit.

[0156] It should be noted that the vehicle 1 provided in the present application may be a pure electric vehicle, a hybrid electric vehicle or an extended-range vehicle, etc., and the present application does not make any special limitation thereto.

[0157] In addition, the vehicle 1 provided in the embodiment of the present application has the same technical effect because it adopts the charging control circuit provided in the embodiment of the present application, and will not be repeated here.

[0158] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A charging control circuit, characterized in that: include: A temperature sensor (101) is used to detect a battery temperature of a battery (102) and output an output voltage corresponding to the battery temperature; a voltage regulating circuit (201), wherein an input end of the voltage regulating circuit (201) is connected to an output end of the temperature sensor (101), and an output end of the voltage regulating circuit (201) is connected to an input end of a charging protection circuit (202), and is used to adjust the output voltage of the temperature sensor (101), so that when the battery temperature of the battery (102) reaches a target temperature threshold, the voltage input to the charging protection circuit (202) is a target voltage, wherein the target temperature threshold is a battery temperature at which the charging protection circuit (202) controls the charger (203) to stop charging the battery (102), and a difference between the target voltage and the power supply voltage of the voltage regulating circuit (201) is greater than a preset voltage value; The charging protection circuit (202), wherein the input end of the charging protection circuit (202) is connected to the output end of the voltage adjustment circuit (201), the output end of the charging protection circuit (202) is connected to the charger (203), and the charging protection circuit (202) is used to compare the voltage output by the voltage adjustment circuit (201) with the target voltage, and output a control signal according to the comparison result to control the charger (203) to be turned off or on.

2. The charging control circuit according to claim 1, characterized in that: The charging control circuit further includes: A first filtering circuit (2010) is connected to the output end of the voltage regulating circuit (201) and is used to filter the adjusted output voltage to obtain a filtered output voltage; A hysteresis circuit (2011) is connected to the output end of the first filter circuit (2010) and is used to control the charger (203) to restart according to the filtered output voltage after the charger (203) is shut down due to over-temperature.

3. The charging control circuit according to claim 2, characterized in that: The charging protection circuit (202) comprises: A comparator (U1) connected to an input end of the drive circuit (2021), used for comparing the filtered output voltage with the target voltage, generating a comparison signal according to the comparison result, and transmitting the comparison signal to the drive circuit (2021); The driving circuit (2021) is connected to the first end of the switch component (M1) and is used to control the switch component (M1) to be turned on or off according to the comparison signal; The switch component (M1), wherein the first end of the switch component (M1) is connected to the output end of the drive circuit (2021), the second end of the switch component (M1) is connected to the charger (203), and the control end of the switch component (M1) is connected to the ground line.

4. The charging control circuit according to claim 3, characterized in that: The charging protection circuit (202) further includes: A pull-up circuit (2022), wherein the pull-up circuit (2022) comprises a first pull-up resistor (R11) and a second pull-up resistor (R21), which are respectively connected to the inverting input terminal and the non-inverting input terminal of the comparator (U1); A target resistor (Rth) is connected to the second pull-up resistor (R21), wherein a resistance value of the target resistor (Rth) is a resistance value of the temperature sensor (101) at a temperature threshold corresponding to the target voltage.

5. The charging control circuit according to claim 4, characterized in that: The voltage adjustment circuit (201) comprises: A first resistor (R12), connected between the temperature sensor (101) and the first pull-up resistor (R11), and used for adjusting the voltage value of the inverting input terminal of the comparator (U1); The second resistor (R22) is connected between the target resistor (Rth) and the second pull-up resistor (R21) and is used to adjust the voltage value of the non-inverting input terminal of the comparator (U1).

6. The charging control circuit according to claim 5, characterized in that: The first filter circuit (2010) comprises: the temperature sensor (101), the first resistor (R12), the first pull-up resistor (R11), a first capacitor (C1) and a third resistor (R13), wherein: A first end of the first resistor (R12) is connected to an output end of the temperature sensor (101), a second end of the first resistor (R12) is connected to a first end of the first pull-up resistor (R11), and a second end of the first pull-up resistor (R11) is connected to a power supply; The first capacitor (C1) is connected in parallel with the third resistor (R13), wherein a first end of the first capacitor (C1) is connected to a ground line, a second end of the first capacitor (C1) is connected to a first end of the first pull-up resistor (R11), a first end of the third resistor (R13) is connected to a ground line, a second end of the third resistor (R13) is connected to a first end of the first pull-up resistor (R11), and a first end of the first pull-up resistor (R11) is connected to an inverting input end of the comparator (U1).

7. The charging control circuit according to claim 6, characterized in that: The hysteresis circuit (2011) comprises: the third resistor (R13) and the fourth resistor (R23), wherein: A first end of the third resistor (R13) is connected to the ground line; A first end of the fourth resistor (R23) is connected to the in-phase input end of the comparator (U1), and a second end of the fourth resistor (R23) is connected to the output end of the comparator (U1).

8. The charging control circuit according to claim 1, characterized in that: The charging control circuit further includes: an analog-to-digital conversion circuit (204), connected to the output end of the temperature sensor (101), and used to perform analog-to-digital conversion on the output voltage of the temperature sensor (101) to generate a target output voltage; The enabling circuit (205) is connected to the charger (203) via a fifth resistor (R3), and is used to receive a control signal sent by a processor, and control the start or stop of the charger (203) according to the control signal sent by the processor, wherein the control signal sent by the processor is a signal generated by the processor according to the magnitude of the target output voltage and the target voltage.

9. The charging control circuit according to claim 8, characterized in that: The analog-to-digital conversion circuit (204) comprises: A sampling circuit, connected to the output end of the temperature sensor (101), and used for sampling the output voltage of the temperature sensor (101); A second filtering circuit is connected to the output end of the sampling circuit and is used to filter the output voltage collected by the sampling circuit to obtain a filtered output voltage; A gain circuit is connected to the output end of the second filter circuit and is used to amplify the filtered output voltage to obtain the target output voltage.

10. The charging control circuit according to claim 9, characterized in that: The sampling circuit comprises: A voltage follower (U2), wherein the inverting input terminal of the voltage follower (U2) is connected to the output terminal of the voltage follower (U2), the non-inverting input terminal of the voltage follower (U2) is connected to the temperature sensor (101), and the output terminal of the voltage follower (U2) is connected to the input terminal of the second filter circuit.

11. The charging control circuit according to claim 10, characterized in that: The gain circuit includes: an amplifier (U3), a sixth resistor (R6), a seventh resistor (R7), an eighth resistor (R8) and a ninth resistor (R9), wherein: The sixth resistor (R6) is connected between the output end of the voltage follower (U2) and the in-phase input end of the amplifier (U3); The first end of the seventh resistor (R7) is connected to the ground line, and the second end of the seventh resistor (R7) is connected to the in-phase input end of the amplifier (U3); A first end of the eighth resistor (R8) is connected to a ground line, and a second end of the eighth resistor (R8) is connected to an inverting input end of the amplifier (U3); The first end of the ninth resistor (R9) is connected to the inverting input end of the amplifier (U3), and the second end of the ninth resistor (R9) is connected to the output end of the amplifier (U3).

12. The charging control circuit according to claim 11, characterized in that: The second filtering circuit comprises: the sixth resistor (R6), the seventh resistor (R7) and a second capacitor (C2), wherein the second capacitor (C2) is connected in parallel with the seventh resistor (R7).

13. A vehicle, characterized in that: A charging control circuit comprising any one of claims 1 to 12.

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