Battery voltage detection circuit, vehicle and mobile phone

Abstract

The present application relates to a battery voltage detection circuit, a vehicle and a mobile phone. The battery voltage detection circuit includes: a voltage division module, a voltage follower module and an A / D conversion module; one end interface of the voltage division module is connected to the output end of the battery, and is configured to divide the output voltage of the battery and input the divided voltage to the voltage follower module; the voltage follower module is connected to the other end interface of the voltage division module, and is configured to detect the divided voltage and output a voltage detection signal; the voltage follower module includes a first transistor and a second transistor, one end of the first transistor is connected to the other end interface of the voltage division module, and the other end is connected to one end of the second transistor; the first transistor and the second transistor are complementary transistor pairs, and the second transistor is a reverse cut-off device; the A / D conversion module is connected to the output interface of the voltage follower module. Through the present application, the problem that the A / D conversion module is woken up again is solved, and the accurate measurement of the battery voltage is realized.

Description

Technical Field

[0001] This application relates to the technical field of batteries, particularly to a battery voltage detection circuit, a vehicle, and a mobile phone. Background Art

[0002] Devices such as in-vehicle devices and mobile phones need to detect the supply voltage of the battery and automatically enter low power consumption or turn off the device when the battery supply voltage is lower than a certain threshold to prevent over-discharge of the battery.

[0003] In the existing solutions, mainly after the battery voltage is divided by a resistor, the battery voltage is detected by using an AD acquisition. However, since the battery is always in the device, the voltage at the battery output interface will always exist when the device is in sleep or shutdown state. Therefore, the battery output voltage will be inverted through the voltage-dividing resistor to the A / D conversion module, causing the A / D conversion module to be woken up again. Summary of the Invention

[0004] In this embodiment, a battery voltage detection circuit, a vehicle, and a mobile phone are provided to solve the problem that the A / D conversion module is woken up again in the related art.

[0005] In the first aspect, in this embodiment, a battery voltage detection circuit is provided, including:

[0006] A voltage-dividing module, a voltage follower module, and an A / D conversion module;

[0007] One end interface of the voltage-dividing module is connected to the output end of the battery, and is used for dividing the output voltage of the battery and inputting the divided voltage to the voltage follower module;

[0008] The voltage follower module is connected to the other end interface of the voltage-dividing module, and is used for detecting the divided voltage and outputting a voltage detection signal; the voltage follower module includes a first transistor and a second transistor. One end of the first transistor is connected to the other end interface of the voltage-dividing module, the other end is connected to one end of the second transistor, and the other end of the second transistor is connected to the A / D conversion module; the first transistor and the second transistor are complementary pair transistors, and the second transistor is a reverse cut-off device;

[0009] The A / D conversion module is connected to the output interface of the voltage follower module, and is used for converting the voltage detection signal into a digital signal.

[0010] In some of these embodiments, the first transistor is an NPN-type triode, the second transistor is a PNP-type triode, and the BE junction of the second transistor is reversely cut off when the power supply of the A / D conversion module is powered off.

[0011] In some of these embodiments, the first transistor is an N-channel field effect transistor, and the second transistor is a P-channel field effect transistor.

[0012] In some of these embodiments, the voltage follower module further includes a first resistor and a second resistor; one end of the first resistor is connected to the first transistor, and the other end is grounded; one end of the second resistor is connected to the second transistor, and the other end is connected to the power input terminal of the A / D conversion module.

[0013] In some of these embodiments, the voltage follower module further includes a first voltage regulator diode, one end of the first voltage regulator diode is connected to the first transistor, and the other end is grounded.

[0014] In some of these embodiments, the voltage follower module further includes a first capacitor and a second capacitor; one end of the first capacitor is connected to the first transistor, and the other end is grounded; one end of the second capacitor is connected to the second transistor, and the other end is grounded.

[0015] In some of these embodiments, the voltage follower module further includes a third resistor, one end of the third resistor is connected to the output terminal of the battery, and the other end is connected to the first transistor.

[0016] In some of these embodiments, the voltage follower module further includes a fourth resistor and a third capacitor; one end of the fourth resistor is connected to the second transistor, and the other end is connected to the A / D conversion module; one end of the third capacitor is connected to the fourth resistor, and the other end is grounded.

[0017] In some of these embodiments, the voltage dividing module includes a fifth resistor and a sixth resistor; one end of the fifth resistor is connected to the output terminal of the battery, and the other end is connected to one end of the sixth resistor, and the other end of the sixth resistor is grounded.

[0018] In some of these embodiments, the voltage dividing module further includes a fourth capacitor, one end of the fourth capacitor is connected to the first transistor, and the other end is grounded.

[0019] In some of these embodiments, a clamping protection module is further included, one end of the clamping protection module is connected to the output terminal of the battery, and the other end is connected to the voltage dividing module, and the clamping protection module is used to keep the output voltage of the battery constant.

[0020] In some of these embodiments, the clamping protection module includes a second voltage regulator diode, a first diode, and a fifth capacitor; one end of the second voltage regulator diode is connected to the output terminal of the battery, and the other end is grounded; one end of the fifth capacitor is connected to the output terminal of the battery; the other end is grounded; one end of the first diode is connected to the output terminal of the battery, and the other end is connected to the voltage division module.

[0021] In a second aspect, a vehicle is provided in this embodiment, including the battery voltage detection circuit as described in the first aspect.

[0022] In a third aspect, a mobile phone is provided in this embodiment, including the battery voltage detection circuit as described in the first aspect.

[0023] Compared with the related art, the battery voltage detection circuit, vehicle, and mobile phone provided in this embodiment, through the voltage division module, voltage follower module, and A / D conversion module; one end interface of the voltage division module is connected to the output terminal of the battery, for dividing the output voltage of the battery and inputting the divided voltage to the voltage follower module; the voltage follower module is connected to the other end interface of the voltage division module, for detecting the divided voltage and outputting a voltage detection signal; the voltage follower module includes a first transistor and a second transistor, one end of the first transistor is connected to the other end interface of the voltage division module, and the other end is connected to one end of the second transistor, and the other end of the second transistor is connected to the A / D conversion module; the first transistor and the second transistor are complementary pair transistors, and the second transistor is a reverse cut-off device; the A / D conversion module is connected to the output interface of the voltage follower module, for converting the voltage detection signal into a digital signal, solving the problem that the A / D conversion module is woken up again, and achieving accurate measurement of the battery voltage.

[0024] The details of one or more embodiments of this application are set forth in the following drawings and description, so that the other features, objects, and advantages of this application will become more concise and understandable. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The drawings described herein are used to provide a further understanding of this application, and form a part of this application. The schematic embodiments of this application and their descriptions are used to explain this application and do not constitute an improper limitation of this application. In the drawings:

[0026] Figure 1 is a schematic structure of a battery voltage detection circuit according to an embodiment of this application Figure 1 ;

[0027] Figure 2 is a schematic structure of a battery voltage detection circuit according to an embodiment of this application Figure 2 ;

[0028] Figure 3 is a schematic diagram of the structure of a battery voltage detection circuit according to an embodiment of the present application Figure 3 ;

[0029] Figure 4 is a schematic diagram of the structure of a battery voltage detection circuit according to an embodiment of the present application Figure 4 ;

[0030] Figure 5 is a schematic diagram of the structure of a battery voltage detection circuit according to an embodiment of the present application Figure 5 ;

[0031] Figure 6 is a schematic diagram of the structure of a battery voltage detection circuit according to an embodiment of the present application Figure 6 ;

[0032] Figure 7 is a schematic diagram of the structure of a battery voltage detection circuit according to an embodiment of the present application Figure 7 ;

[0033] Figure 8 is a schematic diagram of the structure of a battery voltage detection circuit according to an embodiment of the present application Figure 8 ;

[0034] Figure 9 is a schematic diagram of the structure of a battery voltage detection circuit according to an embodiment of the present application Figure 9 ;

[0035] Figure 10 is a schematic diagram of the structure of a battery voltage detection circuit according to an embodiment of the present application Figure 10 ;

[0036] Figure 11 is a schematic diagram of the structure of a battery voltage detection circuit according to an embodiment of the present application Figure 11 One. Detailed implementation manners

[0037] To understand the purpose, technical solution and advantages of the present application more clearly, the present application will be described and illustrated below with reference to the accompanying drawings and embodiments.

[0038] Unless otherwise defined, the technical terms or scientific terms involved in this application shall have the general meanings understood by those with ordinary skills in the technical field to which this application belongs. In this application, words such as "a", "an", "one kind", "the", "these", etc. do not indicate a limitation in quantity, and they can be singular or plural. The terms "include", "comprise", "have" and any variants thereof involved in this application are intended to cover non-exclusive inclusion; for example, a process, method, system, product or device that includes a series of steps or modules (units) is not limited to the listed steps or modules (units), but may include unlisted steps or modules (units), or may include other steps or modules (units) inherent in these processes, methods, products or devices. The words such as "connect", "be connected", "couple" and the like involved in this application are not limited to physical or mechanical connections, but may include electrical connections, whether directly or indirectly. The "plurality" involved in this application means two or more. "And / or" describes the association relationship of associated objects and indicates that three relationships can exist. For example, "A and / or B" can represent: A exists alone, A and B exist simultaneously, and B exists alone. Usually, the character " / " indicates that the objects associated before and after are in an "or" relationship. The terms "first", "second", "third", etc. involved in this application are only used to distinguish similar objects and do not represent a specific sorting of the objects.

[0039] In this embodiment, a battery voltage detection circuit is provided. Figure 1 It is a schematic structural diagram of a battery voltage detection circuit according to an embodiment of the present application. The circuit includes:

[0040] A voltage division module 11, a voltage follower module 12, and an A / D conversion module 13;

[0041] One end interface of the voltage division module is connected to the output terminal 14 of the battery, and is used to divide the output voltage of the battery and input the divided voltage to the voltage follower module 12;

[0042] The voltage follower module 12 is connected to the other end interface of the voltage division module 11, and is used to detect the divided voltage and output a voltage detection signal; the voltage follower module 12 includes a first transistor 15 and a second transistor 16. One end of the first transistor 15 is connected to the other end interface of the voltage division module 11, and the other end is connected to one end of the second transistor 16. The other end of the second transistor 16 is connected to the A / D conversion module 13; the first transistor 15 and the second transistor 16 are complementary pair transistors, and the second transistor 16 is a reverse cut-off device;

[0043] The A / D conversion module 13 is connected to the output interface of the voltage follower module 12, and is used to convert the voltage detection signal into a digital signal.

[0044] It can be understood that, as Figure 1 shown, the second transistor 16 is a reverse cut-off device. Therefore, when the device is turned off or in a sleep state, the battery output voltage will not flow back to the A / D conversion module 13 through the voltage dividing resistor, solving the problem that the A / D conversion module 13 is woken up again. In addition, temperature changes will cause a voltage drop across the second transistor 16, which will further cause the voltage following module 12 to be unable to accurately measure the battery voltage. Therefore, in this embodiment, a first transistor 15 is added, and the first transistor 15 and the second transistor 16 are complementary pair transistors, so that the first transistor 15 can offset the voltage drop generated by the second transistor 16 due to temperature changes, thereby accurately measuring the battery voltage; in addition, the first transistor 15 and the second transistor 16 can amplify the current, making the battery voltage detection circuit have better driving ability.

[0045] It should be noted that complementary pair transistors are two transistors with opposite polarities and the same parameters; the type of the battery is not limited in this embodiment. For example, it can be a lithium battery, a storage battery, or a nickel-metal hydride battery; a reverse cut-off device is a transistor with a reverse cut-off function when the power supply of the A / D conversion module 13 is powered off.

[0046] In some alternative embodiments, the first transistor 15 is an NPN bipolar junction transistor, and the second transistor 16 is a PNP bipolar junction transistor. When the power supply of the A / D conversion module 13 is powered off, the BE junction of the second transistor 16 is reverse cut-off.

[0047] It can be understood that in this embodiment, the first transistor 15 is an NPN bipolar junction transistor, and the second transistor 16 is a PNP bipolar junction transistor, that is, the first transistor 15 is the complementary pair transistor of the second transistor 16. Therefore, the first transistor 15 can offset the voltage drop generated by the second transistor 16 due to temperature changes, thereby accurately measuring the battery voltage; in addition, when the power supply of the A / D conversion module 13 is powered off, the BE junction of the second transistor 16 is reverse cut-off. Therefore, when the device is turned off or in a sleep state, the battery output voltage will not flow back to the A / D conversion module 13 through the voltage dividing resistor, solving the problem that the A / D conversion module 13 is woken up again.

[0048] In some other alternative embodiments, the first transistor 15 is an N-channel field effect transistor, and the second transistor 16 is a P-channel field effect transistor.

[0049] It can be understood that in this embodiment, the first transistor 15 is an N-channel field effect transistor, and the second transistor 16 is a P-channel field effect transistor. That is, the first transistor 15 is the complementary pair transistor of the second transistor 16. Therefore, the first transistor 15 can cancel out the voltage drop generated by the second transistor 16 due to temperature change, so that the voltage of the battery can be accurately measured. In addition, the gate and source of the field effect transistor are insulated. Therefore, when the device is turned off or in a sleep state, the battery output voltage will not flow back to the A / D conversion module 13 through the voltage dividing resistor, solving the problem that the A / D conversion module 13 is woken up again.

[0050] In some alternative embodiments, as Figure 2 shown, the voltage follower module 12 further includes a first resistor 21 and a second resistor 22. One end of the first resistor 21 is connected to the first transistor 15, and the other end is grounded. One end of the second resistor 22 is connected to the second transistor 16, and the other end is connected to the power input terminal 23 of the A / D conversion module.

[0051] It can be understood that the first resistor 21 in this embodiment is a pull-down resistor, and the second resistor 22 is a pull-up resistor. The first resistor 21 provides a sinking current for forming an emitter follower structure or a source follower structure with the first transistor 15. The second resistor 22 provides a sourcing current for forming an emitter follower structure or a source follower structure with the second transistor 16. In addition, the first resistor 21 and the second resistor 22 also play a role in current limiting, preventing excessive current from being transmitted to the first transistor 15 and the second transistor 16, and solving the problem that the first transistor 15 and the second transistor 16 are easily damaged due to excessive current.

[0052] In some alternative embodiments, as Figure 3 shown, the voltage follower module 12 further includes a first voltage regulator diode 31. One end of the first voltage regulator diode 31 is connected to the first transistor 15, and the other end is grounded.

[0053] It can be understood that in this embodiment, the first voltage regulator diode 31 can prevent a relatively high voltage from appearing on the first resistor 21, thereby solving the problem that the second transistor 16 is damaged due to an excessive voltage appearing on the first resistor 21.

[0054] In some alternative embodiments, as Figure 4 shown, the voltage follower module 12 further includes a first capacitor 41 and a second capacitor 42. One end of the first capacitor 41 is connected to the first transistor 15, and the other end is grounded. One end of the second capacitor 42 is connected to the second transistor 16, and the other end is grounded.

[0055] It can be understood that in this embodiment, the first capacitor 41 and the second capacitor 42 can filter out the noise of the voltage. Further, the battery voltage can be detected more accurately through the first transistor 15 and the second transistor 16.

[0056] In some alternative embodiments, as Figure 5 shown, the voltage follower module 12 further includes a third resistor 51. One end of the third resistor 51 is connected to the output terminal 14 of the battery, and the other end is connected to the first transistor 15.

[0057] It can be understood that in this embodiment, the third resistor 51 functions to limit the current, preventing excessive current from being transmitted to the first transistor 15, and solving the problem that the first transistor 15 is prone to damage due to excessive current.

[0058] In some alternative embodiments, as Figure 6 shown, the voltage follower module 12 further includes a fourth resistor 61 and a third capacitor 62; one end of the fourth resistor 61 is connected to the second transistor 16, and the other end is connected to the A / D conversion module 13; one end of the third capacitor 62 is connected to the fourth resistor 61, and the other end is grounded.

[0059] It can be understood that in this embodiment, the fourth resistor 61 and the third capacitor 62 form an RC low-pass filter, which can filter high-frequency noise. Further, the battery voltage detection circuit can more accurately detect the battery voltage.

[0060] In some alternative embodiments, as Figure 7 shown, the voltage dividing module 11 includes a fifth resistor 71 and a sixth resistor 72; one end of the fifth resistor 71 is connected to the output terminal 14 of the battery, the other end is connected to one end of the sixth resistor 72, and the other end of the sixth resistor 72 is grounded.

[0061] It can be understood that in this embodiment, the fifth resistor 71 and the sixth resistor 72 form a voltage divider, which is used to convert the voltage at the output terminal 14 of the battery into a lower voltage that the A / D conversion module 13 can process, so that the battery voltage can be accurately detected by this battery voltage detection circuit.

[0062] In some alternative embodiments, as Figure 8 shown, the voltage dividing module 11 further includes a fourth capacitor 81. One end of the fourth capacitor 81 is connected to the first transistor 71, and the other end is grounded.

[0063] It can be understood that in this embodiment, the fourth capacitor 81 can filter out the voltage noise. Further, the battery voltage can be more accurately detected through the first transistor 15 and the second transistor 16.

[0064] In some alternative embodiments, as Figure 9 shown, the battery voltage detection circuit further includes a clamping protection module 91. One end of the clamping protection module 91 is connected to the output terminal 14 of the battery, and the other end is connected to the voltage dividing module 11. The clamping protection module 91 is used to keep the output voltage of the battery constant.

[0065] It can be understood that in this embodiment, the clamping protection module 91 can prevent the voltage division module 11 from having a relatively high voltage, thereby solving the problem that the first transistor 15 is damaged due to an excessive voltage appearing on the voltage division module 11.

[0066] In some alternative embodiments, such as Figure 10 shown, the clamping protection module 91 includes a second voltage stabilizing diode 101, a first diode 102, and a fifth capacitor 103; one end of the second voltage stabilizing diode 101 is connected to the output terminal 14 of the battery, and the other end is grounded; one end of the fifth capacitor 103 is connected to the output terminal 14 of the battery; the other end is grounded; one end of the first diode 102 is connected to the output terminal 14 of the battery, and the other end is connected to the voltage division module 11.

[0067] It can be understood that in this embodiment, the second voltage stabilizing diode 101 can prevent the voltage division module 11 from having a relatively high voltage, thereby solving the problem that the first transistor 15 is damaged due to an excessive voltage appearing on the voltage division module 11; in addition, the first diode 102 is used to prevent the output terminal voltage of the battery from being connected reversely, resulting in damage to the subsequent circuit; the fifth capacitor 103 can filter out the voltage noise at the output terminal of the battery. Further, the battery voltage can be detected more accurately through the first transistor 15 and the second transistor 16.

[0068] In this embodiment, a vehicle is further provided. The vehicle includes the above battery voltage detection circuit. Therefore, in this embodiment, the battery voltage detection circuit can be used to accurately detect the battery voltage in the vehicle. In addition, it can also prevent the battery output voltage from flowing back to the A / D conversion module 13 through the voltage dividing resistor, solving the problem that the A / D conversion module 13 is awakened again when the vehicle is in a dormant or shutdown state.

[0069] In this embodiment, a mobile phone is further provided. The mobile phone includes the above battery voltage detection circuit. Therefore, in this embodiment, the battery voltage detection circuit can be used to accurately detect the battery voltage in the mobile phone. In addition, it can also prevent the battery output voltage from flowing back to the A / D conversion module 13 through the voltage dividing resistor, solving the problem that the A / D conversion module 13 is awakened again when the mobile phone is in a dormant or shutdown state.

[0070] In some alternative embodiments, such as Figure 11 shown, the battery voltage detection circuit includes: an anti-backflow module 112, an A / D conversion module 13, and a clamping protection module 91. The anti-backflow module 112 includes a voltage division module and a voltage follower module.

[0071] One end of the clamping protection module 91 is connected to the output terminal 14 of the battery, and the other end is connected to the voltage dividing module. The clamping protection module 91 is used to keep the output voltage of the battery constant. The clamping protection module 91 includes a second voltage stabilizing diode 101, a first diode 102, and a fifth capacitor 103. One end of the second voltage stabilizing diode 101 is connected to the output terminal 14 of the battery, and the other end is grounded. One end of the fifth capacitor 103 is connected to the output terminal 14 of the battery, and the other end is grounded. One end of the first diode 102 is connected to the output terminal 14 of the battery, and the other end is connected to the voltage dividing module.

[0072] One end interface of the voltage dividing module is connected to the output terminal of the battery, and is used to divide the output voltage of the battery and input the divided voltage into the voltage follower module. The voltage dividing module includes a fifth resistor 71, a sixth resistor 72, and a fourth capacitor 81. One end of the fifth resistor 71 is connected to the output terminal 14 of the battery, the other end is connected to one end of the sixth resistor 72, and the other end of the sixth resistor 72 is grounded. One end of the fourth capacitor 81 is connected to the NPN type triode 110, and the other end is grounded.

[0073] The voltage follower module is connected to the other end interface of the voltage dividing module, and is used to detect the divided voltage and output a voltage detection signal. The voltage follower module includes an NPN type triode 110, a PNP type triode 111, a first resistor 21, a second resistor 22, a third resistor 51, a fourth resistor 61, a first voltage stabilizing diode 31, a first capacitor 41, a second capacitor 42, and a third capacitor 62.

[0074] One end of the NPN type triode 110 is connected to the other end interface of the voltage dividing module, the other end is connected to one end of the PNP type triode 111, and the other end of the PNP type triode 111 is connected to the A / D conversion module 13. The NPN type triode 110 and the PNP type triode 111 are complementary pair transistors, and the BE junction of the PNP type triode 111 is reversely cut off when the power supply of the A / D conversion module 13 is powered off.

[0075] One end of the first resistor 21 is connected to the NPN type triode 110, and the other end is grounded. One end of the second resistor 22 is connected to the PNP type triode 111, and the other end is connected to the power input terminal 23 of the A / D conversion module 13.

[0076] The NPN transistor 110 and the first resistor 21 form a first emitter follower, which is used to mirror the voltage after voltage division by the voltage division module to the emitter output interface of the NPN transistor 110. The PNP transistor 111 and the second resistor 22 form a second emitter follower, which is used to mirror the voltage on the first resistor 21 to the emitter output interface of the PNP transistor 111. The first emitter follower and the second emitter follower form a complementary structure, which is used to cancel the Vbe voltage drop of the PNP transistor 111 and the influence of the change in Vbe caused by temperature changes, so as to ensure that within the designed temperature range, the voltage at the emitter of the PNP transistor 111 is exactly equal to the voltage after voltage division by the voltage division module;

[0077] One end of the first voltage regulator diode 31 is connected to the NPN transistor 110, and the other end is grounded; one end of the first capacitor 41 is connected to the NPN transistor 110, and the other end is grounded; one end of the second capacitor 42 is connected to the PNP transistor 111, and the other end is grounded;

[0078] One end of the third resistor 51 is connected to the output terminal 14 of the battery, and the other end is connected to the NPN transistor 110; one end of the fourth resistor 61 is connected to the PNP transistor 111, and the other end is connected to the A / D conversion module 13; one end of the third capacitor 62 is connected to the fourth resistor 61, and the other end is grounded;

[0079] The A / D conversion module 13 is connected to the output interface of the voltage follower module, and is used to convert the voltage detection signal into a digital signal.

[0080] In this embodiment, the first resistor 21 is a pull-down resistor, and the second resistor 22 is a pull-up resistor. The first resistor 21 provides a sinking current and is used to form an emitter follower structure or a source follower structure with the NPN transistor 110; the second resistor 22 provides a sourcing current and is used to form an emitter follower structure or a source follower structure with the PNP transistor 111; in addition, the first resistor 21 and the second resistor 22 also play a current limiting role, which is used to prevent too high a current from being transmitted to the NPN transistor 110 and the PNP transistor 111, and solves the problem that the NPN transistor 110 and the PNP transistor 111 are easily damaged due to too high a current. The third resistor 51 plays a current limiting role to prevent too high a current from being transmitted to the NPN transistor 110. The fourth resistor 61 and the third capacitor 62 form an RC low-pass filter, which can filter high-frequency noise;

[0081] The first voltage regulator diode 31 can prevent a relatively high voltage from appearing on the first resistor 21, thereby solving the problem that the PNP transistor 111 is damaged due to too high a voltage appearing on the first resistor 21;

[0082] The first capacitor 41 and the second capacitor 41 can filter out the noise of the voltage. The fourth capacitor 81 can filter out the noise of the voltage. The second voltage regulator diode 101 can prevent a relatively high voltage from appearing in the voltage dividing module, thereby solving the problem that the NPN transistor 110 is damaged due to an excessive voltage appearing in the voltage dividing module. The first diode 102 is used to prevent the output terminal voltage of the battery from being connected reversely, resulting in damage to the subsequent circuit. The fifth capacitor 103 can filter out the noise of the output terminal voltage of the battery. The fifth resistor 71 and the sixth resistor 72 form a voltage divider for converting the output terminal voltage 14 of the battery into a lower voltage that the A / D conversion module 13 can process. The fourth capacitor 81 can filter out the noise of the voltage.

[0083] Exemplarily, the output voltage Vbat of the battery is determined by the following formula, where VQ22 is the output voltage of the emitter of the PNP transistor 111, Vbe is the BE junction voltage drop of the PNP transistor 111, which is also the BE junction voltage drop of the NPN transistor 110, VD1 is the conduction voltage drop of the first diode 102, R1 is the resistance value of the fifth resistor 71, and R2 is the resistance value of the sixth resistor 72.

[0084]

[0085] Since Vbe changes with temperature, it will cause the detected Vbat to change with temperature and the change amount of Vbat is larger than the change amount of Vbe itself because it has to be multiplied by (R1 + R2) / R2. Based on this, an NPN transistor 110 is added. The BE junction voltage drops of the NPN transistor 110 and the PNP transistor 111 are basically the same and also change basically the same with temperature, which can offset the influence of the Vbe of the PNP transistor 111. Because the voltage at the emitter terminal of the NPN transistor 110 is as shown in the following formula.

[0086]

[0087] The voltage VQ22 at the emitter terminal of the NPN transistor 110 is obtained by the following formula.

[0088] VQ22 = VQ12 + Vbe (3)

[0089] From this, it can be obtained that the voltage VQ22 at the emitter terminal of the PNP transistor 111 is as shown in the following formula.

[0090]

[0091] It can be seen from formula (4) that the influence of the BE junction voltage drop of the PNP transistor 111 is eliminated, so that the output voltage of the battery can be accurately detected at the emitter terminal of the PNP transistor 111.

[0092] It can be understood that in this embodiment, when the power supply of the A / D conversion module 13 is powered off, the BE junction of the PNP transistor 111 is reversely cut off. Therefore, when the device is turned off or in the sleep state, the battery output voltage will not be back-fed to the A / D conversion module 13 through the voltage-dividing resistor, solving the problem that the A / D conversion module 13 is awakened again. In addition, when the device is powered on again, there will be no problem that the A / D conversion module 13 cannot be awakened and the device cannot work properly. If there is no battery voltage detection circuit of this embodiment in the device, when the device is turned off or in the sleep state, the battery output voltage will be back-fed to the A / D conversion module 13 through the voltage-dividing resistor, which may lead to the risk that the power-on timing does not meet the requirements when the A / D conversion module 13 is powered on again. Therefore, there is a risk that the A / D conversion module 13 cannot be awakened or the device cannot work properly. In addition, temperature changes will cause a voltage drop in the PNP transistor 111, which will further cause the voltage follower module to be unable to accurately measure the battery voltage. Therefore, in this embodiment, an NPN transistor 110 is added, and the NPN transistor 110 and the PNP transistor 111 are complementary pairs of transistors. Thus, the NPN transistor 110 can offset the voltage drop generated by the PNP transistor 111 due to temperature changes, so that the battery voltage can be accurately measured. In addition, the NPN transistor 110 and the PNP transistor 111 can amplify the current, making the battery voltage detection circuit have better driving ability.

[0093] It should be understood that the specific embodiments described herein are only used to explain this application and not to limit it. According to the embodiments provided in this application, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of this application.

[0094] Obviously, the drawings are only some examples or embodiments of this application. For those of ordinary skill in the art, this application can also be applied to other similar situations according to these drawings without creative work. In addition, it can be understood that although the work done during the development process may be complex and time-consuming, for those of ordinary skill in the art, certain design, manufacturing, or production changes based on the technical content disclosed in this application are only conventional technical means and should not be regarded as insufficient disclosure of this application.

[0095] The term "embodiment" in this application means that the specific features, structures, or characteristics described in connection with the embodiment may be included in at least one embodiment of this application. The phrase appears in various positions in the specification does not necessarily mean the same embodiment, nor does it mean independence or alternative to other embodiments. Those of ordinary skill in the art can clearly or implicitly understand that the embodiments described in this application can be combined with other embodiments without conflict.

[0096] The above embodiments merely illustrate several implementation manners of the present application. The description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of patent protection. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several variations and improvements can still be made, and these all fall within the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the appended claims.

Claims

1. A battery voltage detection circuit, characterized in that, Comprising: A voltage division module, a voltage follower module, and an A / D conversion module; One end interface of the voltage division module is connected to the output end of the battery, and is used for dividing the output voltage of the battery and inputting the divided voltage to the voltage follower module; The voltage follower module is connected to the other end interface of the voltage division module, and is used for detecting the divided voltage and outputting a voltage detection signal; the voltage follower module includes a first transistor and a second transistor, the first transistor and the second transistor are complementary paired transistors, and the second transistor is a reverse cut-off device; the complementary paired transistors are two transistors with opposite polarities and consistent parameters; the transistor is a triode or a field effect transistor; the base or gate of the first transistor is connected to the other end interface of the voltage division module, the emitter or source of the first transistor is connected to the base or gate of the second transistor; the collector or drain of the second transistor is grounded; the voltage follower module further includes a first resistor and a second resistor; one end of the first resistor is connected to the emitter or source of the first transistor, and the other end is grounded; one end of the second resistor is connected to the emitter or source of the second transistor, and the other end is connected to the power input end of the A / D conversion module; the voltage follower module further includes a third resistor, one end of the third resistor is connected to the output end of the battery, and the other end is connected to the collector or drain of the first transistor; The A / D conversion module is connected to the output interface of the voltage follower module, and is used for converting the voltage detection signal into a digital signal.

2. The battery voltage detection circuit according to claim 1, characterized in that, The first transistor is an NPN type triode, the second transistor is a PNP type triode, and the BE junction of the second transistor is reversely cut off when the power supply of the A / D conversion module is powered off.

3. The battery voltage detection circuit according to claim 1, wherein The first transistor is an N-channel field effect transistor, and the second transistor is a P-channel field effect transistor.

4. The battery voltage detection circuit according to claim 1, wherein The voltage follower module further includes a first voltage stabilizing diode, one end of the first voltage stabilizing diode is connected to the emitter or source of the first transistor, and the other end is grounded.

5. The battery voltage detection circuit according to claim 1, wherein The voltage follower module further includes a first capacitor and a second capacitor; one end of the first capacitor is connected to the collector or drain of the first transistor, and the other end is grounded; one end of the second capacitor is connected to the base or gate of the second transistor, and the other end is grounded.

6. The battery voltage detection circuit according to claim 1, characterized in that The voltage follower module further includes a fourth resistor and a third capacitor; one end of the fourth resistor is connected to the emitter or source of the second transistor, and the other end is connected to the A / D conversion module; one end of the third capacitor is connected to the fourth resistor, and the other end is grounded.

7. The battery voltage detection circuit according to claim 1, wherein The voltage division module includes a fifth resistor and a sixth resistor; one end of the fifth resistor is connected to the output end of the battery, the other end is connected to one end of the sixth resistor, and the other end of the sixth resistor is grounded.

8. The battery voltage detection circuit according to claim 7, characterized in that, The voltage division module further includes a fourth capacitor, one end of the fourth capacitor is connected to the base or gate of the first transistor, and the other end is grounded.

9. The battery voltage detection circuit according to claim 1, wherein It further includes a clamping protection module. One end of the clamping protection module is connected to the output end of the battery, and the other end is connected to the voltage division module. The clamping protection module is used to keep the output voltage of the battery constant.

10. The battery voltage detection circuit according to claim 9, wherein, The clamping protection module includes a second voltage stabilizing diode, a first diode and a fifth capacitor; one end of the second voltage stabilizing diode is connected to the output end of the battery, and the other end is grounded; one end of the fifth capacitor is connected to the output end of the battery; the other end is grounded; one end of the first diode is connected to the output end of the battery, and the other end is connected to the voltage division module.

11. A vehicle, characterized in that, It includes the battery voltage detection circuit according to any one of claims 1-10.

12. A mobile phone, characterized in that, It includes the battery voltage detection circuit according to any one of claims 1-10.

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