Low-voltage protection circuit, vehicle-mounted device and automobile

Abstract

The utility model discloses a low-voltage protection circuit, a vehicle-mounted device and an automobile, and relates to the technical field of electronic circuits, and the disclosed low-voltage protection circuit comprises a detection chip and a plurality of acquisition modules. The detection chip is connected with the first end of each acquisition module, and the second end of each acquisition module is connected with a vehicle-mounted storage battery. When the detection chip receives the detection voltage of the vehicle-mounted storage battery output by any acquisition module, the detection voltage is compared with the reference voltage, and when the detection voltage is lower than the preset reference voltage, the power supply loop between the vehicle-mounted storage battery and the power supply load is disconnected, so that the power supply load is prevented from being damaged when the storage battery voltage output by the vehicle-mounted storage battery is too low. Therefore, the service life of the vehicle-mounted storage battery is prolonged.

Description

TECHNICAL FIELD

[0001] The utility model relates to electronic circuit technical field especially relates to a low voltage protection circuit, vehicle-mounted device and car. BACKGROUND

[0002] The vehicle battery on the car is connected with the power supply load (such as a car data recorder) through a step-down line, and the vehicle battery forms a power supply loop with the power supply load through the step-down line, so that the vehicle battery supplies power to the power supply load through the power supply loop. However, when the vehicle battery supplies power to the power supply load, the battery will be damaged due to excessive discharge when the voltage output by the vehicle battery is too low.

[0003] The above content is only used to assist in understanding the technical scheme of the utility model and does not represent that the above content is prior art. UTILITY MODEL CONTENT

[0004] The main purpose of the utility model is to provide a low voltage protection circuit, vehicle-mounted device and car, which aims to solve the technical problem that the battery will be damaged due to excessive discharge when the voltage output by the vehicle battery is too low in the prior art.

[0005] To achieve the above purpose, the utility model provides a low voltage protection circuit, which comprises a detection chip and a plurality of acquisition modules.

[0006] The detection chip is connected with the first end of each acquisition module, and the second end of each acquisition module is connected with the vehicle battery.

[0007] The detection chip is used for comparing the detection voltage of the vehicle battery output by any acquisition module with a reference voltage when receiving the detection voltage.

[0008] The detection chip is also used for disconnecting the power supply loop between the vehicle battery and the power supply load when the detection voltage is lower than the reference voltage.

[0009] In an embodiment, the acquisition module is used for acquiring the battery voltage output by the vehicle battery to the power supply load.

[0010] The acquisition module is also used for outputting the detection voltage to the detection chip after dividing the battery voltage.

[0011] In an embodiment, the acquisition module comprises at least a first acquisition module and a second acquisition module.

[0012] The first end of the first acquisition module is connected with the first pin of the detection chip, and the second end of the first acquisition module is connected with the vehicle-mounted storage battery.

[0013] In an embodiment, the first acquisition module comprises a first resistor, a second resistor and a first capacitor.

[0014] The first end of the first resistor is connected with the vehicle-mounted storage battery, the second end of the first resistor is connected with the first end of the second resistor, the first end of the first capacitor and the first pin of the detection chip respectively, and the second end of the second resistor and the second end of the first capacitor are grounded.

[0015] In an embodiment, the second acquisition module comprises a third resistor, a fourth resistor and a second capacitor.

[0016] The first end of the third resistor is connected with the vehicle-mounted storage battery, the second end of the third resistor is connected with the first end of the fourth resistor, the first end of the second capacitor and the second pin of the detection chip respectively, and the second end of the fourth resistor and the second end of the second capacitor are grounded.

[0017] In an embodiment, the circuit further comprises a voltage reduction module.

[0018] The voltage reduction module is connected with the vehicle-mounted storage battery and the power supply load respectively.

[0019] The voltage reduction module is configured to receive the storage battery voltage output by the vehicle-mounted storage battery.

[0020] The voltage reduction module is further configured to convert the storage battery voltage into a target voltage and supply power to the power supply load based on the target voltage.

[0021] The detection chip is further configured to output a control signal to control the voltage reduction module to stop running when the detection voltage is lower than the reference voltage, so as to disconnect the power supply loop between the vehicle-mounted storage battery and the power supply load.

[0022] In an embodiment, the voltage reduction module comprises a first voltage reduction chip, a first fuse, a first Schottky diode, a first inductor, a fifth resistor and a third capacitor.

[0023] The first pin of the first voltage reduction chip is connected with the cathode of the first Schottky diode and the first end of the third capacitor respectively, the anode of the first Schottky diode is connected with the first end of the first fuse, the second end of the first fuse is connected with the vehicle battery, and the second end of the third capacitor is grounded.

[0024] The second pin of the first voltage reduction chip is connected with the first end of the first inductor.

[0025] The third pin of the first voltage reduction chip is connected with the second end of the first inductor and the first end of the fifth resistor respectively.

[0026] The fourth pin of the first voltage reduction chip is connected with the second end of the fifth resistor and the power supply load respectively.

[0027] In an embodiment, the voltage reduction module further comprises a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a fourth capacitor, a fifth capacitor and a sixth capacitor.

[0028] The fifth pin of the first voltage reduction chip is connected with the first end of the sixth resistor, and the second end of the sixth resistor is connected with the third pin of the detection chip.

[0029] The sixth pin of the first voltage reduction chip is connected with the first end of the seventh resistor and the first end of the fourth capacitor respectively.

[0030] The second end of the fourth capacitor, the first end of the eighth resistor, the first end of the fifth capacitor and the first end of the sixth capacitor are connected with the power supply load, the second end of the seventh resistor, the first end of the ninth resistor, the second end of the fifth capacitor and the second end of the sixth capacitor are grounded, and the second end of the eighth resistor is connected with the second end of the ninth resistor.

[0031] In an embodiment, the circuit further comprises a power supply module.

[0032] The power supply module is connected with the vehicle battery and the detection chip respectively.

[0033] The power supply module is configured to receive a battery voltage output by the vehicle battery.

[0034] The power supply module is further configured to supply power to the detection chip based on the battery voltage.

[0035] In an embodiment, the power supply module comprises a second voltage reduction chip, a tenth resistor, a seventh capacitor and an eighth capacitor.

[0036] The first pin of the second voltage reduction chip is connected with the vehicle battery and the first end of the seventh capacitor respectively.

[0037] The second pin of the second voltage reduction chip is connected with the first end of the eighth capacitor, the first end of the tenth resistor and the fourth pin of the detection chip respectively, and the second end of the tenth resistor is connected with the fifth pin of the detection chip;

[0038] The third pin of the second voltage reduction chip, the second end of the seventh capacitor and the second end of the eighth capacitor are grounded.

[0039] In an embodiment, the circuit further comprises a power supply detection module;

[0040] The power supply detection module is connected with an accessory power supply and the detection chip respectively;

[0041] The power supply detection module is configured to turn on a ground return circuit of the detection chip when receiving a power supply voltage output by the accessory power supply, so as to input a first level signal into the detection chip;

[0042] The detection chip is further configured to output a first state signal representing that the accessory power supply is in an output state according to the first level signal.

[0043] In an embodiment, the power supply detection module is further configured to turn off the ground return circuit of the detection chip when not receiving the power supply voltage output by the accessory power supply;

[0044] The detection chip is further configured to receive a second level signal output by the power supply module when the ground return circuit is turned off;

[0045] The detection chip is further configured to output a second state signal representing that the accessory power supply is in an off state according to the second level signal.

[0046] In an embodiment, the power supply detection module comprises a first switch tube, an eleventh resistor and a twelfth resistor;

[0047] The control end of the first switch tube is connected with the first end of the eleventh resistor and the first end of the twelfth resistor respectively, and the second end of the eleventh resistor is connected with the accessory power supply;

[0048] The input end of the first switch tube is connected with the fifth pin of the detection chip;

[0049] The output end of the first switch tube and the second end of the twelfth resistor are grounded.

[0050] In addition, in order to achieve the above object, the utility model further provides a vehicle-mounted device, the vehicle-mounted device includes low voltage protection circuit as described above.

[0051] In addition, in order to achieve the above object, the utility model also provides an automobile, the automobile includes vehicle battery, accessory power supply and power supply load,

[0052] The vehicle battery, the accessory power supply and the power supply load are connected through a step-down line,

[0053] The step-down line is equipped with the low-voltage protection circuit as described above,

[0054] The one or more technical schemes provided by the utility model have at least the following technical effects:

[0055] The low-voltage protection circuit provided by the utility model includes: a detection chip and a plurality of acquisition modules; the detection chip is connected with the first end of each acquisition module respectively, and the second end of each acquisition module is connected with the vehicle battery. BRIEF DESCRIPTION OF DRAWINGS

[0056] The drawings incorporated into the specification and forming a part thereof show, in accordance with the present application, embodiments and, together with the specification, serve to explain the principle of the application.

[0057] In order to more clearly illustrate the technical scheme in the embodiments of the present application or prior art, the drawings needed to be used in the embodiment or prior art description will be briefly introduced as follows, and obviously, other drawings can also be obtained by those skilled in the art without creative labor under the premise of these drawings.

[0058] Figure 1 It is a structural schematic view of the low-voltage protection circuit first embodiment of the utility model,

[0059] Figure 2 It is a structural schematic view of part acquisition module in the first embodiment of the utility model,

[0060] Figure 3 It is a circuit principle diagram of acquisition module in the first embodiment of the utility model,

[0061] Figure 4 It is a flow schematic view of the low-voltage protection circuit second embodiment of the utility model,

[0062] Figure 5 It is a circuit principle diagram of step-down module in the second embodiment of the utility model,

[0063] Figure 6 Structure diagram of the power supply module in the second embodiment of the utility model;

[0064] Figure 7 Circuit principle diagram of the power supply module in the second embodiment of the utility model;

[0065] Figure 8 Structure diagram of the third embodiment of the low-voltage protection circuit of the utility model;

[0066] Figure 9 Circuit principle diagram of the power supply detection module in the third embodiment of the utility model.

[0067] Explanation of reference numerals:

[0068]

[0069]

[0070] The utility model aims at realizing, function characteristics and advantages will be further explained in combination with embodiments, with reference to the drawings. DETAILED DESCRIPTION

[0071] It should be understood that the specific embodiments described herein are only used to explain the utility model scheme, and are not used to limit the utility model.

[0072] In order to better understand the technical scheme of the utility model, the following will be explained in detail in combination with the drawings of the specification and specific embodiments.

[0073] The main solution of the embodiment of the utility model is: at least detection chip and multiple acquisition modules are arranged in the low-voltage protection circuit, the detection chip is connected with the first end of each acquisition module respectively, and the second end of each acquisition module is connected with the vehicle battery.

[0074] Because the vehicle battery of the prior art is powered when the voltage output by the vehicle battery is too low, the battery will be damaged due to excessive discharge.

[0075] The utility model provides a kind of solution, when detection chip receives the detection voltage of vehicle battery output by any acquisition module, detection voltage is compared with reference voltage, when detection voltage is lower than preset reference voltage, the power supply loop between vehicle battery and power supply load is disconnected, so it can avoid that battery voltage output by vehicle battery is too low, due to excessive discharge and damage, prolong the service life of vehicle battery.

[0076] Based on this, the embodiment of the utility model proposes a kind of low-voltage protection circuit, with reference to Figure 1 , Figure 1 Structure diagram of the first embodiment of the low-voltage protection circuit of the utility model.

[0077] In this embodiment, the low-voltage protection circuit includes a detection chip U0 and multiple acquisition modules.

[0078] The detection chip U0 is connected to the first end of each of the acquisition modules, and the second end of each acquisition module is connected to the vehicle battery.

[0079] like Figure 1 As shown, the acquisition module includes a first acquisition module 101, a second acquisition module 102, ..., an Nth acquisition module n. The number of acquisition modules can be set according to requirements. The first end of each acquisition module is connected to the pin corresponding to the detection chip U0, and the second end of each acquisition module is connected to the vehicle battery.

[0080] It should be noted that the vehicle battery and the power supply load are connected via a step-down cable to form a power supply circuit. The vehicle battery can output its voltage through this power supply circuit to the power supply load, thus supplying power to the load. The power supply load can be various devices in the vehicle that receive power from the vehicle battery, such as a dashcam.

[0081] The detection chip U0 is used to compare the detection voltage with a reference voltage when it receives the detection voltage of the vehicle battery output by any of the acquisition modules.

[0082] It should be noted that the aforementioned reference voltage can be used as a threshold for determining whether the detection voltage is too low. When the detection voltage is low, it can be assumed that the battery voltage output by the vehicle battery is below a safe value.

[0083] In the specific implementation, each acquisition module can convert the battery voltage output from the vehicle battery to the power supply load into a detection voltage. The detection chip U0 can receive the detection voltage output by each acquisition module through the corresponding pin and compare any detection voltage with the reference voltage.

[0084] The detection chip U0 is also used to disconnect the power supply circuit between the vehicle battery and the power supply load when the detection voltage is lower than the preset reference voltage.

[0085] In practical implementation, a protection device, such as a step-down circuit or a switching transistor, can be installed between the vehicle battery and the power supply load. This protection device is in a closed state by default, ensuring the power supply circuit between the vehicle battery and the power supply load is open. This protection device is connected to the corresponding pin of the detection chip U1 and is controlled by U1. When the detection chip U1 outputs a corresponding signal to control the protection device to open, the power supply circuit between the vehicle battery and the power supply load is disconnected. This protection device can also have a step-down function to reduce the battery voltage output by the vehicle battery to a value supported by the power supply load, ensuring that the vehicle battery can supply power to the load.

[0086] Based on this, when the detection chip U0 detects that the detection voltage is lower than the reference voltage, it can be determined that the battery voltage output by the vehicle-mounted battery is lower than the safety value, that is, the battery voltage is too low, and a corresponding signal can be output to control the protection device in the power supply loop to be disconnected, thereby disconnecting the power supply loop between the vehicle-mounted battery and the power supply load, and achieving low-voltage protection of the vehicle-mounted battery.

[0087] In order to improve the detection accuracy, the control chip U0 can execute low-voltage protection when the detection voltage is continuously lower than the reference voltage within a preset time (such as 5s), and output a corresponding control signal to control the protection device in the power supply loop to be disconnected.

[0088] Further, in the embodiment, the acquisition module is configured to acquire the battery voltage output by the vehicle-mounted battery to the power supply load.

[0089] The acquisition module is further configured to output the detection voltage to the detection chip after voltage division of the battery voltage.

[0090] In a specific implementation, each acquisition module can acquire the battery voltage output by the vehicle-mounted battery to the power supply load, and each acquisition module can be provided with a voltage division circuit to divide the battery voltage and output the detection voltage to the detection chip U0.

[0091] For ease of understanding, refer to Figure 2 , Figure 2 The first embodiment of the utility model is partially shown in the structure diagram of the acquisition module. The first embodiment and the following embodiments are described with reference to the first acquisition module 101 and the second acquisition module 102 shown in the figure, but the scheme is not limited to this. For other acquisition modules, refer to the description of the first acquisition module 101 and the second acquisition module 102 in the first embodiment and the following embodiments, which will not be described here. Figure 2

[0092] As shown in the figure, the acquisition module at least includes the first acquisition module 101 and the second acquisition module 102. Figure 2

[0093] The first end of the first acquisition module 101 is connected with the first pin 1 of the detection chip U0, the second end of the first acquisition module 101 is connected with the vehicle-mounted battery, the second end of the second acquisition module 102 is connected with the second pin 2 of the detection chip U0, and the second end of the second acquisition module 102 is connected with the vehicle-mounted battery.

[0094] Among them, the first acquisition module 101 and the second acquisition module 102 are configured to acquire the battery voltage output by the vehicle-mounted battery to the power supply load, and output the detection voltage to the detection chip U0 after voltage division of the battery voltage.

[0095] ​​For ease of understanding, with reference to Figure 3 described, but not limited to the present solution, Figure 3 is the circuit principle diagram of the collecting module in the first embodiment of the utility model. Figure 3 In the embodiment, the first collecting module 101 comprises a first resistor R1, a second resistor R2 and a first capacitor C1; a first end of the first resistor R1 is connected with the vehicle-mounted battery, a second end of the first resistor R1 is connected with a first end of the second resistor R2, a first end of the first capacitor C1 and a first pin of the detection chip U0 respectively, and a second end of the second resistor R2 and a second end of the first capacitor C1 are grounded GND.

[0096] The second collecting module 102 comprises a third resistor R3, a fourth resistor R4 and a second capacitor C2; a first end of the third resistor R3 is connected with the vehicle-mounted battery, a second end of the third resistor R3 is connected with a first end of the fourth resistor R4, a first end of the second capacitor C2 and a second pin 2 of the detection chip U0 respectively, and a second end of the fourth resistor R4 and a second end of the second capacitor C2 are grounded GND.

[0097] In the specific implementation, the first collecting module 101 can collect the battery voltage output by the vehicle-mounted battery through the first resistor R1, the second resistor R2 and the first capacitor C1, the first resistor R1 and the second resistor R2 constitute a voltage dividing circuit for dividing the battery voltage, and the detection voltage is output to the first pin 1 of the detection chip U0. The second collecting module 102 can collect the battery voltage output by the vehicle-mounted battery through the third resistor R3, the fourth resistor R4 and the second capacitor C2, the third resistor R3 and the fourth resistor R4 constitute a voltage dividing circuit for dividing the battery voltage, and the detection voltage is output to the second pin 2 of the detection chip U0. The above-mentioned first capacitor C1 and second capacitor C2 are used to filter the high-frequency noise and ripple in the battery voltage output by the vehicle-mounted battery, and improve the accuracy of collection.

[0098] The low-voltage protection circuit provided in the embodiment comprises a detection chip and a plurality of collecting modules; the detection chip is connected with the first end of each collecting module, and the second end of each collecting module is connected with the vehicle-mounted battery. Since the detection chip of the embodiment compares the detection voltage with the reference voltage when receiving the detection voltage of the vehicle-mounted battery output by any collecting module, and disconnects the power supply loop between the vehicle-mounted battery and the power supply load when the detection voltage is lower than the preset reference voltage, the vehicle-mounted battery output can be prevented from being damaged due to excessive discharge when the battery voltage is too low, and the service life of the vehicle-mounted battery is prolonged.

[0099] Based on the first embodiment of the utility model, the second embodiment of the utility model is provided. In the second embodiment of the utility model, the same or similar contents as the first embodiment can be referred to the foregoing description, and the subsequent description will not be repeated. On this basis, please refer to Figure 4 , Figure 4 It is the flow chart of the second embodiment of the utility model low-voltage protection circuit.

[0100] In the embodiment, the low-voltage protection circuit further comprises a voltage reduction module 200.

[0101] The voltage reduction module 200 is connected with the vehicle battery and the power supply load respectively.

[0102] The device composed of the voltage reduction module 200 or the device provided with the voltage reduction module 200 can be the protection device described in the foregoing embodiments.

[0103] The voltage reduction module 200 is used for receiving the battery voltage output by the vehicle battery.

[0104] In the specific implementation, the input end of the voltage reduction module 200 is connected with the vehicle battery, and the output end is connected with the power supply load, and the three constitute a power supply loop. The voltage reduction module 200 can receive the battery voltage output by the vehicle battery through the power supply loop.

[0105] The voltage reduction module 200 is also used for converting the battery voltage into a target voltage and supplying power to the power supply load based on the target voltage.

[0106] It should be noted that the target voltage can be the voltage supported by the power supply load.

[0107] In the specific implementation, the voltage reduction module 200 can reduce the battery voltage output by the vehicle battery through the internal voltage reduction loop to obtain the target voltage, and then output the target voltage to the power supply load to realize the power supply to the power supply load.

[0108] The detection chip U0 is also used for outputting a control signal to control the voltage reduction module 200 to stop running when the detection voltage is lower than the reference voltage, so as to disconnect the power supply loop between the vehicle battery and the power supply load.

[0109] In the specific implementation, the control end of the voltage reduction module 200 can be connected with the third pin 3 of the detection chip U0. When the detection voltage is lower than the reference voltage, the third pin 3 of the detection chip U0 can output a control signal to the voltage reduction module 200. After receiving the control signal, the voltage reduction module 200 disconnects the internal circuit and stops running, so as to disconnect the power supply loop between the vehicle battery and the power supply load.

[0110] For the convenience of understanding, refer toFigure 5 The utility model discloses a circuit principle diagram of the voltage reduction module in the second embodiment of the utility model. Figure 5 Figure 5 The voltage reduction module 200 includes a first voltage reduction chip U1, a first fuse F1, a first Schottky diode D1, a first inductor L1, a fifth resistor R5, and a third capacitor C3.

[0111] The first pin VIN of the first voltage reduction chip U1 is connected to the cathode of the first Schottky diode D1 and the first end of the third capacitor C3, respectively. The anode of the first Schottky diode D1 is connected to the first end of the first fuse F1. The second end of the first fuse F1 is connected to the vehicle battery. The second end of the third capacitor C3 is grounded GND. The second pin SW1 of the first voltage reduction chip U1 is connected to the first end of the first inductor L1. The third pin S- of the first voltage reduction chip U1 is connected to the second end of the first inductor L1 and the first end of the fifth resistor R5, respectively. The fourth pin S+ of the first voltage reduction chip U1 is connected to the second end of the fifth resistor R5 and the power supply load, respectively.

[0112] Further, the voltage reduction module 200 further includes a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a fourth capacitor C4, a fifth capacitor C5, and a sixth capacitor C6.

[0113] The fifth pin EN of the first voltage reduction chip U1 is connected to the first end of the sixth resistor R6. The second end of the sixth resistor R6 is connected to the third pin 3 of the detection chip U0. The sixth pin FR of the first voltage reduction chip U1 is connected to the first end of the seventh resistor R7 and the first end of the fourth capacitor C4, respectively. The second end of the fourth capacitor C4, the first end of the eighth resistor R8, the first end of the fifth capacitor C5, and the first end of the sixth capacitor C6 are all connected to the power supply load. The second end of the seventh resistor R7, the first end of the ninth resistor R9, the second end of the fifth capacitor C5, and the second end of the sixth capacitor C6 are all grounded GND. The second end of the eighth resistor R8 is connected to the second end of the ninth resistor R9. The seventh pin G of the first voltage reduction chip U1 is grounded GND.

[0114] In addition, the third pin 3 of the detection chip U0 is also grounded GND through a thirteenth resistor R3.

[0115] ​In a specific implementation, the first voltage reduction chip U1, the first fuse F1, the first Schottky diode D1, the first inductor L1, the fifth resistor R5, the third capacitor C3, the sixth resistor R6, the seventh resistor R7, the eighth resistor R8, the ninth resistor R9, the fourth capacitor C4, the fifth capacitor C5, and the sixth capacitor C6 of the above-mentioned voltage reduction module 200 constitute a voltage reduction circuit. The battery voltage output by the vehicle-mounted battery is output to the first voltage reduction chip U1 through the first fuse F1, the first Schottky diode D1, and the third capacitor C3, the first voltage reduction chip U1 reduces the battery voltage, and the voltage after reduction is converted into a target voltage through the first inductor L1, the fifth resistor R5, the fourth capacitor C4, the seventh resistor R7, the eighth resistor R8, the ninth resistor R9, the fifth capacitor C5, and the sixth capacitor C6, and then output to the power supply load to supply power to the power supply load.

[0116] It should be understood that when the detection chip U0 detects that the detection voltage is lower than the reference voltage, the control signal is output to the sixth resistor R6 through the third pin 3 of the detection chip U0, and the fifth pin EN of the first voltage reduction chip U1 is disconnected when receiving the control signal of the detection chip U0 through the sixth resistor R6, thereby disconnecting the voltage reduction circuit formed by the first voltage reduction chip U1, stopping the power supply to the power supply load, and achieving protection of the vehicle-mounted battery.

[0117] It should be noted that after the power supply circuit is disconnected, if the battery voltage output by the vehicle-mounted battery returns to the normal level, that is, the detection voltage received by the detection chip reaches the reference voltage, a corresponding signal can be output to drive the first voltage reduction chip to run again, so that the power supply circuit between the vehicle-mounted battery and the power supply load is restored.

[0118] It can be understood that the low-voltage protection circuit of the embodiment can support low-voltage protection of vehicle-mounted batteries with different battery voltages, and different battery voltages can be configured with different reference voltages. Assuming that the range of battery voltage is 8V-30V, and taking a vehicle-mounted battery with an output of 12V battery voltage and a vehicle-mounted battery with an output of 24V battery voltage as an example. When the vehicle-mounted battery with an output of 12V battery voltage is connected, the low-voltage threshold can be set to 11.8V, and assuming that the detection voltage obtained by the voltage division of the 11.8V battery voltage by the acquisition module is 1.53V, the detection voltage of 1.53V can be used as the reference voltage. When the detection chip detects that the detection voltage is lower than 1.53V, it is determined that the battery voltage is lower than 11.8V, and the first voltage reduction chip U1 can be controlled to be disconnected, thereby disconnecting the power supply circuit. When the battery voltage recovers, that is, greater than or equal to 11.8V, the control chip U0 can drive the first voltage reduction chip U1 again, turn on the power supply circuit between the vehicle-mounted battery and the power supply load, and restore the power supply to the power supply load.

[0119] When the vehicle battery connected with 24V battery voltage, the low voltage threshold can be set as 23.8V, assuming that the detection voltage of 3.055V is obtained by dividing the battery voltage of 23.8V through the acquisition module, the detection voltage of 3.055V can be used as the reference voltage, when the detection chip detects that the detection voltage is lower than 3.055V, it is determined that the battery voltage is lower than 23.8V, the first voltage reduction chip U1 can be controlled to be disconnected, so as to disconnect the power supply circuit; when the battery voltage recovers, that is, greater than or equal to 23.8V, because the battery voltage is high, the control chip U0 can delay a certain time, such as 2 minutes, and then drive the first voltage reduction chip U1 again, the power supply circuit between the vehicle battery and the power supply load is turned on, and the power supply of the power supply load is restored.

[0120] Further, referring to Figure 6 , Figure 6 It is a structure schematic view of the power supply module in the second embodiment of the utility model.

[0121] In the embodiment, the low voltage protection circuit further comprises a power supply module 300.

[0122] The power supply module 300 is connected with the vehicle battery and the detection chip U0 respectively.

[0123] The power supply module 300 is used for receiving the battery voltage output by the vehicle battery.

[0124] In the specific implementation, the power supply module 300 can form a power supply circuit with the vehicle battery and the detection chip U0, and the battery voltage output by the vehicle battery is received through the power supply circuit.

[0125] The power supply module 300 is further used for supplying power to the detection chip U0 based on the battery voltage.

[0126] In the specific implementation, the power supply module 300 can convert the received battery voltage into a chip voltage supported by the detection chip U0, and output the chip voltage to the detection chip U0, so as to supply power to the detection chip U0.

[0127] For the convenience of understanding, reference Figure 7 is made for illustration, but does not limit the scheme. Figure 7 It is a circuit principle view of the power supply module in the second embodiment of the utility model. Figure 7 In the embodiment, the power supply module 300 comprises a second voltage reduction chip U2, a tenth resistor R10, a seventh capacitor C7 and an eighth capacitor C8.

[0128] The first pin VDD of the second voltage reduction chip U2 is connected with the vehicle storage battery and the first end of the seventh capacitor C7 respectively; the second pin OUT of the second voltage reduction chip U2 is connected with the first end of the eighth capacitor C8, the first end of the tenth resistor R10 and the fourth pin 4 of the detection chip U0 respectively, the second end of the tenth resistor R10 is connected with the fifth pin 5 of the detection chip, and the third pin VSS of the second voltage reduction chip U2, the second end of the seventh capacitor C7 and the second end of the eighth capacitor C8 are all grounded GND.

[0129] In a specific implementation, the second voltage reduction chip U2, the tenth resistor R10, the seventh capacitor C7 and the eighth capacitor C8 of the power supply module 300 constitute a voltage reduction loop. The storage battery voltage output by the vehicle storage battery is output to the second voltage reduction chip U2 through the seventh capacitor C7, the second voltage reduction chip U2 reduces the storage battery voltage, obtains a chip voltage, and then outputs the chip voltage to the fourth pin 4 of the detection chip U0 through the eighth capacitor C8 and the tenth resistor R10, so as to supply power to the detection chip U0 and enable the detection chip U0 to operate normally.

[0130] For example, assuming that the storage battery voltage is 12V, the chip voltage output to the detection chip U0 after being reduced by the second voltage reduction chip U2 can be 5V, and the detection chip U0 is powered by the 5V chip voltage and is started.

[0131] The voltage reduction module of the embodiment is connected with the vehicle storage battery and the power supply load respectively, and the power supply module is connected with the vehicle storage battery and the detection chip respectively. When the detection voltage is lower than the reference voltage, the detection chip outputs a control signal to control the voltage reduction module to stop operating, so that the power supply loop between the vehicle storage battery and the power supply load is disconnected, and the precision of the low-voltage protection is effectively improved. Moreover, the power supply module supplies power to the detection chip by the storage battery voltage, so as to ensure that the detection chip can operate stably, and further ensure that the low-voltage protection function can be realized stably.

[0132] Based on the first embodiment and the second embodiment of the utility model, the third embodiment of the utility model is proposed. In the third embodiment of the utility model, the same or similar contents as the above first embodiment and the second embodiment can be referred to the above introduction, and the subsequent will not be described in detail. On this basis, please refer to Figure 8 , Figure 8 It is a structure schematic view of the third embodiment of the utility model low-voltage protection circuit.

[0133] In the embodiment, the low-voltage protection circuit further comprises a power supply detection module 400.

[0134] The power supply detection module 400 is connected with the accessory power supply and the detection chip U0 respectively.

[0135] The power supply detection module 400 is configured to turn on a ground loop of the detection chip U0 when receiving a power supply voltage output by the accessory power supply, so as to input a first level signal to the detection chip U0.

[0136] It should be noted that the accessory power supply can be a power supply connected with an ignition key switch of the automobile, and is configured to supply power to accessory devices (such as a sound system, an air conditioner, a vehicle lamp, a power window, etc.) requiring power supply when the vehicle is started, and the accessory power supply can be composed of an Accessory (ACC) circuit.

[0137] For the convenience of understanding, the power supply detection module 400 will be described below with reference to Figure 9 but the present solution is not limited thereto. Figure 9 The circuit principle diagram of the power supply detection module in the third embodiment of the present application. Figure 9 The power supply detection module 400 includes a first switch tube Q1, an eleventh resistor R11 and a twelfth resistor R12.

[0138] The control end of the first switch tube Q1 is connected with the first end of the eleventh resistor R11 and the first end of the twelfth resistor R12 respectively, the second end of the eleventh resistor R11 is connected with the accessory power supply, the input end of the first switch tube Q1 is connected with the fifth pin 5 of the detection chip U0, and the output end of the first switch tube Q1 and the second end of the twelfth resistor R12 are both grounded GND. The sixth pin 6 of the detection chip U0 is grounded GND.

[0139] In a specific implementation, the first switch tube Q1 is described as an NPN type triode. When the vehicle is in a running state, the accessory power supply can output a power supply voltage to the base of the first switch tube Q1, the first switch tube Q1 is closed, the fifth pin 5 of the detection chip U0 is grounded, and a low-level first level signal is input to the fifth pin 5 of the detection chip U0.

[0140] The detection chip U0 is configured to output a first state signal representing that the accessory power supply is in an output state according to the first level signal.

[0141] In a specific implementation, the low-voltage protection circuit can further include a fourteenth resistor R14, a first end of the fourteenth resistor R14 being connected to the seventh pin 7 of the detection chip U0, and a second end of the fourteenth resistor R14 being an output end and being connectable to an accessory device. When the fifth pin 5 of the detection chip U0 receives the first-level signal, it can be determined that the vehicle is in a running state, and at this time, the seventh pin 7 of the detection chip U0 can output a first state signal to the accessory device through the fourteenth resistor R14. The first state signal can represent that the accessory power supply is in an output state, and can be used to detect whether the vehicle is in a running state. The voltage of the first state signal can be a voltage supported by the accessory device for receiving. By outputting the first state signal to the accessory device, power supply can be provided for the accessory device, and normal operation of the accessory device can be ensured.

[0142] In the embodiment, the power supply detection module 400 is further configured to disconnect the ground loop of the detection chip when the power supply voltage output by the accessory power supply is not received.

[0143] In a specific implementation, when the vehicle is turned off, the accessory power supply stops outputting the power supply voltage, and at this time, the base of the first switch tube Q1 is disconnected because the power supply voltage cannot be received, so that the ground loop of the detection chip U0 is disconnected.

[0144] The detection chip U0 is further configured to receive a second-level signal output by the power supply module when the ground loop is disconnected.

[0145] In a specific implementation, when the ground loop of the detection chip U0 is disconnected, the tenth resistor R10 of the power supply module 300 can serve as a pull-up resistor, and the second voltage reduction chip U2 can output a high-level second-level signal to the fifth pin 5 of the detection chip U0 through the tenth resistor R10 to pull up the fifth pin 5 of the detection chip U0.

[0146] The detection chip U0 is further configured to output a second state signal representing that the accessory power supply is in a disconnected state according to the second-level signal.

[0147] In a specific implementation, after the fifth pin 5 of the detection chip U0 receives the second-level signal, the seventh pin of the detection chip U0 can output a second state signal, which can represent that the accessory power supply is in a disconnected state, and can be used to detect whether the vehicle is in an off state. After the detection chip U0 outputs the second state signal, power supply for the accessory device is stopped.

[0148] The power supply detection module of the embodiment is connected with the accessory power supply and the detection chip respectively. When the power supply detection module receives the power supply voltage output by the accessory power supply, the ground loop of the detection chip is turned on, so that the first level signal is input to the detection chip, and the detection chip can output the first state signal representing that the accessory power supply is in the output state based on the first level signal, thereby supplying power to the accessory device. When the power supply detection module does not receive the power supply voltage output by the accessory power supply, the ground loop of the detection chip is turned off, so that the detection chip receives the second level signal output by the power supply module, and the detection chip outputs the second state signal representing that the accessory power supply is in the off state based on the second level signal, thereby stopping supplying power to the accessory device. Since the accessory power supply can output the power supply voltage when the vehicle is in the running state, and the accessory power supply stops outputting the power supply voltage when the vehicle is in the off state, the above power supply detection module can accurately detect the state of the vehicle, and then control the power supply to the accessory device according to the state of the vehicle.

[0149] In addition, the utility model discloses a kind of vehicle-mounted devices, and the vehicle-mounted device includes the low-voltage protection circuit described in the above embodiment.

[0150] In addition, the utility model discloses a kind of automobile, and the automobile includes vehicle battery, accessory power supply and power supply load.

[0151] The vehicle battery, the accessory power supply and the power supply load are connected by a step-down line.

[0152] The step-down line is provided with the low-voltage protection circuit described in the above embodiment.

[0153] The specific implementation mode of the vehicle-mounted device and the automobile of the utility model can refer to each embodiment of the above low-voltage protection circuit, which will not be described here.

[0154] It should be noted that, in this paper, the term "including", "containing" or any other variant thereof is intended to cover non-exclusive inclusion, so that the process, method, article or system including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or includes elements inherent to such process, method, article or system. Without more limitations, the element defined by the sentence "including a …" does not exclude the presence of another identical element in the process, method, article or system including the element.

[0155] The above embodiment serial number of the utility model is only for description, not representing the pros and cons of the embodiment.

[0156] The above are only preferred embodiments of the present application, and do not limit the patent range of the present application, and any equivalent structure or equivalent process transformation made by using the content of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection range of the present application.

Claims

1. A low voltage protection circuit, characterized by, The circuit comprises a detection chip and a plurality of acquisition modules; The detection chip is connected with the first end of each acquisition module, and the second end of each acquisition module is connected with the vehicle storage battery; The detection chip is configured to compare the detection voltage of the vehicle storage battery output by any acquisition module with a reference voltage when the detection voltage is received; The detection chip is further configured to disconnect the power supply loop between the vehicle storage battery and the power supply load when the detection voltage is lower than the reference voltage.

2. The low voltage protection circuit of claim 1, wherein, The acquisition module comprises at least a first acquisition module and a second acquisition module; The first end of the first acquisition module is connected with the first pin of the detection chip, the second end of the first acquisition module is connected with the vehicle storage battery, the second end of the second acquisition module is connected with the second pin of the detection chip, and the second end of the second acquisition module is connected with the vehicle storage battery, all of which are configured to acquire the storage battery voltage output by the vehicle storage battery to the power supply load, and output the detection voltage to the detection chip after voltage division of the storage battery voltage.

3. The low voltage protection circuit of claim 2, wherein, The first acquisition module comprises a first resistor, a second resistor and a first capacitor; The second acquisition module comprises a third resistor, a fourth resistor and a second capacitor; The first end of the first resistor is connected with the vehicle storage battery, the second end of the first resistor is connected with the first end of the second resistor, the first end of the first capacitor and the first pin of the detection chip respectively, and the second end of the second resistor and the second end of the first capacitor are grounded; The first end of the third resistor is connected with the vehicle storage battery, the second end of the third resistor is connected with the first end of the fourth resistor, the first end of the second capacitor and the second pin of the detection chip respectively, and the second end of the fourth resistor and the second end of the second capacitor are grounded.

4. The low voltage protection circuit of claim 1, wherein, The circuit further comprises a step-down module; The step-down module is connected with the vehicle storage battery and the power supply load respectively; The step-down module is configured to receive the storage battery voltage output by the vehicle storage battery; The step-down module is further configured to convert the storage battery voltage into a target voltage and supply power to the power supply load based on the target voltage; The detection chip is further configured to output a control signal to control the step-down module to stop running when the detection voltage is lower than the reference voltage, so as to disconnect the power supply loop between the vehicle storage battery and the power supply load.

5. The low voltage protection circuit of claim 4, wherein, The step-down module comprises a first step-down chip, a first fuse, a first Schottky diode, a first inductor, a fifth resistor, a third capacitor, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a fourth capacitor, a fifth capacitor and a sixth capacitor; The first pin of the first step-down chip is connected with the cathode of the first Schottky diode and the first end of the third capacitor respectively, the anode of the first Schottky diode is connected with the first end of the first fuse, the second end of the first fuse is connected with the vehicle storage battery, and the second end of the third capacitor is grounded; The second pin of the first step-down chip is connected with the first end of the first inductor; The third pin of the first voltage reduction chip is connected with the second end of the first inductor and the first end of the fifth resistor respectively; The fourth pin of the first voltage reduction chip is connected with the second end of the fifth resistor and the power supply load respectively; The fifth pin of the first voltage reduction chip is connected with the first end of the sixth resistor, and the second end of the sixth resistor is connected with the third pin of the detection chip; The sixth pin of the first voltage reduction chip is connected with the first end of the seventh resistor and the first end of the fourth capacitor respectively; The second end of the fourth capacitor, the first end of the eighth resistor, the first end of the fifth capacitor and the first end of the sixth capacitor are connected with the power supply load, the second end of the seventh resistor, the first end of the ninth resistor, the second end of the fifth capacitor and the second end of the sixth capacitor are grounded, and the second end of the eighth resistor is connected with the second end of the ninth resistor.

6. A low voltage protection circuit as claimed in any one of claims 1 to 5, characterized in that, The circuit further comprises a power supply module; The power supply module comprises a second voltage reduction chip, a tenth resistor, a seventh capacitor and an eighth capacitor; The first pin of the second voltage reduction chip is connected with the vehicle battery and the first end of the seventh capacitor respectively; The second pin of the second voltage reduction chip is connected with the first end of the eighth capacitor, the first end of the tenth resistor and the fourth pin of the detection chip respectively, and the second end of the tenth resistor is connected with the fifth pin of the detection chip; The third pin of the second voltage reduction chip, the second end of the seventh capacitor and the second end of the eighth capacitor are grounded.

7. The low voltage protection circuit of claim 6, wherein, The circuit further comprises a power supply detection module; The power supply detection module is connected with an accessory power supply and the detection chip respectively; The power supply detection module is configured to, when receiving a power supply voltage output by the accessory power supply, turn on a ground loop of the detection chip to input a first level signal to the detection chip; The detection chip is further configured to output a first state signal representing that the accessory power supply is in an output state according to the first level signal.

8. The low voltage protection circuit of claim 7, wherein, The power supply detection module comprises a first switch tube, an eleventh resistor and a twelfth resistor; The control end of the first switch tube is connected with the first end of the eleventh resistor and the first end of the twelfth resistor respectively, and the second end of the eleventh resistor is connected with the accessory power supply; The input end of the first switch tube is connected with the fifth pin of the detection chip; The output end of the first switch tube and the second end of the twelfth resistor are grounded.

9. An in-vehicle device characterized by comprising: The vehicle-mounted device comprises the low-voltage protection circuit according to any one of claims 1 to 8.

10. An automobile characterized by comprising: The automobile comprises a vehicle battery, an accessory power supply and a power supply load; The vehicle battery, the accessory power supply and the power supply load are connected through a voltage reduction line; The voltage reduction line is provided with the low-voltage protection circuit according to any one of claims 1 to 8.

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