Main and standby power switching circuit

Abstract

The utility model provides a main and standby power switching circuit, which comprises a main battery unit and a standby battery unit, wherein the main battery unit and the standby battery unit directly supply power to a switching unit or supply power to the switching unit through a booster circuit; the power output end of the switching unit is connected with the input end of the power module; the output end of the power supply module is connected with the power supply end of the charging chip and the post-stage circuit. The signal output end of the switching unit is connected with the signal receiving end of the control module; the output end of the charging chip is connected with the input end of the standby battery unit; the enabling end of the control module is connected with the control end of the charging chip; when the switching unit adopts the standby battery unit to supply power, the enabling end of the control module outputs a disable signal; when the switching unit switches out the standby battery, the switching unit can transmit the switched-out signal to the control module through the signal output end of the switching unit. The control module can control the charging chip to stop working through the enabling end of the control module, so that the standby battery and the charging chip are prevented from forming a discharging sneak loop and electric quantity loss, and the endurance time is prolonged.

Description

Technical Field

[0001] The utility model belongs to the technical field of power electronics, and more specifically, particularly relates to a main and standby power switching circuit. Background Art

[0002] During the design process of an in-vehicle terminal, a rescue function needs to be provided for the vehicle. The working characteristics of the vehicle's rescue function require that the backup battery of the in-vehicle terminal can work at a temperature of -20°C, and a call duration of 10 minutes plus a satellite search endurance time of 60 minutes is required. Among them, satellite search is the connection between the user terminal part and the space satellite, so as to determine the position of the user terminal and achieve the purpose of positioning.

[0003] Currently, the main battery and the backup battery are used alternately to supply power to the in-vehicle terminal; in order to ensure the continuity of power supply and the realizability of the rescue function, when the main battery is used to supply power to the in-vehicle terminal, the backup battery is disconnected to avoid insufficient power of the backup battery to realize the rescue function; when the main battery is disconnected or under-voltage, the backup battery is used to supply power to the in-vehicle terminal.

[0004] However, since there is a discharge latent circuit in the backup battery in the circuit, that is, when the backup battery is used to supply power to the in-vehicle terminal, the backup battery will charge itself through the charging path, that is, the discharge latent circuit, which will cause power loss and shorten the endurance time. Summary of the Utility Model

[0005] In view of this, the purpose of the utility model is to provide a main and standby power switching circuit, which is used to control the charging chip to turn off when the backup battery unit is cut in, and extend the endurance time of the backup battery unit.

[0006] The present application discloses a main and standby power switching circuit, including: a main battery unit, a backup battery unit, a switching unit, a boost circuit, a power supply module, a charging chip and a control module;

[0007] The output end of the main battery unit is connected to the first input end of the switching unit;

[0008] The output end of the backup battery unit is connected to the second input end of the switching unit through the boost circuit;

[0009] The power output end of the switching unit is connected to the input end of the power supply module;

[0010] The output end of the power supply module is respectively connected to the power supply end of the charging chip and the subsequent circuit;

[0011] The signal output end of the switching unit is connected to the signal receiving end of the control module;

[0012] The output terminal of the charging chip is connected to the input terminal of the backup battery unit;

[0013] The enable terminal of the control module is connected to the control terminal of the charging chip; when the switching unit is powered by the backup battery unit, the enable terminal of the control module outputs a disabling signal.

[0014] Optionally, the control terminal of the switching unit is connected to the control terminal of the control module.

[0015] Optionally, the switching unit includes: a detection unit and a switching unit;

[0016] The first input terminal of the detection unit receives the output signal of the primary battery unit;

[0017] The second input terminal of the detection unit serves as the control terminal of the switching unit;

[0018] The output terminal of the detection unit is connected to the control terminal of the switching unit, and the connection point serves as the signal output terminal of the switching unit;

[0019] The first input terminal of the switching unit serves as the first input terminal of the switching unit;

[0020] The second input terminal of the switching unit serves as the second input terminal of the switching unit;

[0021] The output terminal of the switching unit serves as the power output terminal of the switching unit.

[0022] Optionally, the switching unit includes: a first capacitor, a second capacitor, a third capacitor, a first switching transistor, a second switching transistor, a third switching transistor, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, and a seventh resistor;

[0023] The first end of the first switching transistor is connected to one end of the first capacitor, and the connection point serves as the second input terminal of the switching unit;

[0024] The second end of the first switching transistor is respectively connected to the second end of the second switching transistor, one end of the first resistor, and one end of the second resistor;

[0025] The control terminal of the first switching transistor is respectively connected to the other end of the first resistor and one end of the third resistor;

[0026] The first end of the second switching transistor is respectively connected to one end of the second capacitor and one end of the seventh resistor, and the connection point serves as the output terminal of the switching unit;

[0027] The control terminal of the second switching transistor is respectively connected to the other end of the second resistor and one end of the fourth resistor;

[0028] The other end of the third resistor is respectively connected to the other end of the fourth resistor and the first end of the third switching transistor;

[0029] The control end of the third switching transistor is respectively connected to one end of the fifth resistor and one end of the sixth resistor;

[0030] The other end of the fifth resistor serves as the control end of the switching unit;

[0031] The other end of the seventh resistor is connected to one end of the third capacitor, and the connection point serves as the first input end of the switching unit;

[0032] The other ends of the first capacitor, the second capacitor, the third capacitor, the second end of the third switching transistor, and the other end of the sixth resistor are grounded.

[0033] Optionally, the detection unit includes: a first diode, a second diode, a fourth switching transistor, an eighth resistor, a ninth resistor, a tenth resistor, and an eleventh resistor;

[0034] The anode of the first diode serves as the first input end of the detection unit;

[0035] The cathode of the first diode is connected to one end of the eleventh resistor;

[0036] The other end of the eleventh resistor is respectively connected to one end of the tenth resistor and the cathode of the second diode;

[0037] One end of the eighth resistor serves as the second input end of the detection unit;

[0038] The other end of the eighth resistor is respectively connected to the anode of the second diode, the control end of the fourth switching transistor, and the first end of the fourth switching transistor;

[0039] The other end of the tenth resistor is grounded;

[0040] The second end of the fourth switching transistor serves as the output end of the detection unit.

[0041] Optionally, it further includes: a driving unit;

[0042] The first end of the driving unit is connected to the signal output end of the switching unit;

[0043] The second end of the driving unit is connected to the enable end of the control module;

[0044] The third end of the driving unit is connected to the control end of the charging chip.

[0045] Optionally, the driving unit includes: a twelfth resistor, a thirteenth resistor, a fourteenth resistor, a fifteenth resistor, a sixteenth resistor, and a fifth switching transistor;

[0046] One end of the twelfth resistor serves as the first end of the driving unit;

[0047] The other end of the twelfth resistor is respectively connected to the control end of the fifth switching transistor and one end of the thirteenth resistor;

[0048] The first end of the fifth switching transistor is connected to one end of the fifteenth resistor;

[0049] The other end of the fifteenth resistor is respectively connected to one end of the fourteenth resistor and one end of the sixteenth resistor, and the connection point serves as the third end of the driving unit;

[0050] The other end of the sixteenth resistor serves as the second end of the driving unit;

[0051] The other end of the thirteenth resistor, the second end of the fifth switching transistor, and the other end of the fourteenth resistor are all grounded.

[0052] Optionally, it further includes: an anti-reverse unit;

[0053] The anti-reverse unit is arranged between the main battery unit and the switching unit.

[0054] Optionally, it further includes: a voltage stabilizing unit and a filtering unit;

[0055] The voltage stabilizing unit and the filtering unit are arranged between the main battery unit and the switching unit.

[0056] Optionally, it further includes a detection unit;

[0057] The detection unit is used to detect the information of the main and standby power switching circuit and transmit it to the control module; wherein the information of the main and standby power switching circuit includes: the temperature of the standby battery unit, the output voltage and output current of the charging chip.

[0058] As can be seen from the above technical solutions, a main and backup power switching circuit provided by the present utility model includes: the output end of the main battery unit is connected to the first input end of the switching unit; the output end of the backup battery unit is connected to the second input end of the switching unit through a boost circuit; the power output end of the switching unit is connected to the input end of the power module; the output end of the power module is respectively connected to the power supply end of the charging chip and the subsequent circuit; the signal output end of the switching unit is connected to the signal receiving end of the control module; the output end of the charging chip is connected to the input end of the backup battery unit; the enable end of the control module is connected to the control end of the charging chip; when the switching unit is powered by the backup battery unit, the enable end of the control module outputs a disabling signal; when the switching unit cuts out the backup battery, the cut-out signal can be transmitted to the control module through its own signal output end; the control module can control the charging chip to stop working through its own enable end, avoiding the formation of a discharge latent circuit and power loss between the backup battery and the charging chip, and prolonging the battery life. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0060] Figure 1 is a schematic diagram of a main and backup power switching circuit provided by an embodiment of the present utility model;

[0061] Figure 2 is a schematic diagram of another main and backup power switching circuit provided by an embodiment of the present utility model;

[0062] Figure 3 is a schematic diagram of another main and backup power switching circuit provided by an embodiment of the present utility model;

[0063] Figure 4 is a schematic diagram of another main and backup power switching circuit provided by an embodiment of the present utility model;

[0064] Figure 5 is a schematic diagram of another main and backup power switching circuit provided by an embodiment of the present utility model. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0065] To make the objectives, technical solutions, and advantages of the embodiments of the present utility model clearer, the technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model. Apparently, the described embodiments are some but not all of the embodiments of the present utility model. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.

[0066] In this application, the term "including", "comprising", or any other variation thereof is intended to cover non-exclusive inclusion, such that a process, method, article, or device including a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. Without further limitation, an element defined by the phrase "including a..." does not exclude the presence of additional identical elements in the process, method, article, or device including the element.

[0067] The embodiment of this application provides a main and backup power switching circuit, which is used to solve the problem in the prior art that there is a discharge potential loop in the backup battery in the circuit. That is, when the backup battery is used to supply power to the vehicle-mounted terminal, the backup battery will charge itself through the charging path, that is, the discharge potential loop, thereby causing power loss and shortening the battery life.

[0068] See Figure 1 , the main and backup power switching circuit includes: a main battery unit, a backup battery unit, a switching unit, a boost circuit, a power supply module, a charging chip, and a control module.

[0069] The output terminal of the main battery unit is connected to the first input terminal of the switching unit.

[0070] The output terminal of the main battery unit transmits electrical energy, such as voltage and other signals, to the first input terminal of the switching unit. Then, the switching unit can transmit the electrical energy signal at its first input terminal to its output terminal, so that the electrical energy of the main battery unit can be transmitted to the power output terminal of the switching unit.

[0071] The main battery unit can be an automotive battery unit. The power supply module can be the primary power supply module of the vehicle-mounted terminal.

[0072] Optionally, it may further include: an anti-reverse unit.

[0073] The anti-reverse unit is arranged between the main battery unit and the switching unit.

[0074] The anti-reverse unit can prevent the backup battery unit from charging the main battery unit in reverse.

[0075] The input end of the anti - reverse unit is connected to the output end of the primary battery unit; the output end of the anti - reverse unit is connected to the input end of the switching unit.

[0076] The anti - reverse unit may include an anti - reverse diode; the anode of the anti - reverse diode serves as the input end of the anti - reverse unit; the cathode of the anti - reverse diode serves as the output end of the anti - reverse unit.

[0077] The number of anti - reverse diodes in the anti - reverse unit can be multiple or 1, and no specific limitation is made here. It depends on the actual situation and is within the protection scope of this application.

[0078] Optionally, it further includes: a voltage - stabilizing unit and a filtering unit.

[0079] The voltage - stabilizing unit and the filtering unit are arranged between the primary battery unit and the switching unit.

[0080] Specifically, the input end of the voltage - stabilizing unit is connected to the output end of the primary battery unit; the output end of the voltage - stabilizing unit is connected to the input end of the filtering unit; the output end of the filtering unit is connected to the input end of the first switching unit.

[0081] When including the anti - reverse unit, the input end of the anti - reverse unit is connected to the output end of the primary battery unit; the input end of the voltage - stabilizing unit is connected to the output end of the anti - reverse unit; the output end of the voltage - stabilizing unit is connected to the input end of the filtering unit; the output end of the filtering unit is connected to the input end of the first switching unit.

[0082] Of course, the positions of the voltage - stabilizing unit and the filtering unit can also be swapped, or the anti - reverse unit can be swapped with any one of the voltage - stabilizing unit and the filtering unit. Details are not elaborated here. It depends on the actual situation and is within the protection scope of this application.

[0083] The output end of the backup battery unit is connected to the second input end of the switching unit through a boost circuit.

[0084] The output end of the backup battery unit transmits electrical energy, such as signals like voltage, to the second input end of the switching unit. Then, the switching unit can transmit the electrical energy signal at its second input end to its output end, enabling the electrical energy of the backup battery unit to be transmitted to the power output end of the switching unit.

[0085] The switching unit can cut in or cut out the backup battery unit, that is, it can control the backup battery unit to supply power to the vehicle - mounted terminal, such as supplying power to the subsequent circuit; it can also control the backup battery unit to stop supplying power to the vehicle - mounted terminal, such as stopping supplying power to the subsequent circuit.

[0086] The power output end of the switching unit is connected to the input end of the power module.

[0087] The power supply module can process the electrical energy signal output from the power output terminal of the switching unit, such as performing AC-DC conversion or amplification processing, etc. The functions of the power supply module are not limited here and can be determined according to the actual situation, all within the protection scope of this application.

[0088] The switching unit can make a judgment based on the output voltage of the primary battery unit. When the output voltage of the primary battery unit is less than the threshold voltage, it controls the backup battery unit to cut in for power supply, seamlessly realizing the automatic switching between the primary battery unit and the backup battery unit for use by the power supply module.

[0089] The output terminals of the power supply module are respectively connected to the power supply terminal of the charging chip and the subsequent circuit.

[0090] That is to say, after processing the received electrical energy signal, the power supply module supplies power to the charging chip and the subsequent circuit.

[0091] When the charging chip receives power supply, it can work normally. Of course, it can also control the charging chip to stop working when the charging chip receives power supply.

[0092] After receiving power supply, the subsequent circuit can work normally, such as running normally or performing rescue searches, etc.

[0093] The signal output terminal of the switching unit is connected to the signal receiving terminal of the control module.

[0094] That is to say, the state of the switching unit can be transmitted to the signal receiving terminal of the control module through its own output terminal. When the switching unit is in different states, it can realize the cutting in or out of the backup battery unit. For example, when the switching unit is in the cutting-in state, it can cut in the backup battery unit. When the switching unit is in the cutting-out state, it can cut out the backup battery unit. Furthermore, the control module can know whether the backup battery unit is cut in or out.

[0095] It should be noted that the switching unit can also realize the cutting in or out of the primary battery unit, which is not specifically limited here and can be determined according to the actual situation, all within the protection scope of this application.

[0096] The output terminal of the charging chip is connected to the input terminal of the backup battery unit.

[0097] Furthermore, the charging chip can charge the backup battery. For example, when the backup battery unit is cut out and needs to be charged, the charging chip can use the electrical energy of the primary battery unit or other power sources to charge the backup battery unit; that is, the input voltage of the charging chip can directly come from the output voltage of the primary battery unit.

[0098] Such as Figure 2As shown, a MOS transistor can be set between the output terminal of the charging chip and the input terminal of the backup battery unit.

[0099] Figure 2 Each English character in it is the corresponding node or the voltage of the corresponding node. Specifically:

[0100] UBD: The main power voltage provided by the main battery unit; UB_PR: The voltage after UBD passes through the reverse protection unit; UB_VCC: The voltage after the main power voltage UBD of the main battery unit passes through reverse protection, voltage regulation, and π filtering; UB_VCC_IN: The input terminal of the power module; VBAT_BOOST_8V3: The output voltage of 8.3V of the backup battery unit after passing through the boost circuit, used to supply the subsequent stage power supply; VCC5V_BAT: The output voltage of the power module; VBAT: The positive output voltage of the backup battery unit; CHARGE_PWM: The PWM signal provided by the control module to the charging chip; BAT_CHARGE_SHUTDOWN: The signal output terminal of the switching unit, which can also be understood as the flag when switching the backup battery unit. High level represents switching to the backup battery unit, and low level represents using the main battery unit.

[0101] The enable terminal of the control module is connected to the control terminal of the charging chip; when the switching unit is powered by the backup battery unit, the enable terminal of the control module outputs a disable signal.

[0102] The boost circuit can be a BOOST boost circuit.

[0103] When the switching unit is powered by the backup battery unit, the backup battery unit discharges. The backup battery unit first passes through the boost circuit for boosting to VBAT_BOOST8V3, and then inputs to the power module.

[0104] Since the output voltage of the backup battery unit cannot reach the input voltage requirement of the primary power supply, it needs to be boosted by the BOOST boost circuit to reach, which is the set output voltage value of the BOOST boost circuit.

[0105] VBAT_BOOST_8V3 is the voltage of 8.3V output by the backup battery unit after being boosted by the BOOST boost circuit, used to supply the subsequent stage power supply.

[0106] The control module can be an MCU. Of course, it can also be other devices, which are not specifically limited here and can be determined according to the actual situation, and all are within the protection scope of this application.

[0107] As can be seen from the foregoing description, the control module can receive the status information output by the switching unit. Since the control module can process the status information, it can then control the operating status of the charging chip through the enable terminal of the control module. When the switching unit is powered by the backup battery unit, that is, when the switching unit controls the backup unit to cut in, the enable terminal of the control module outputs a disabling signal to control the charging chip to turn off and stop working. When the switching unit is powered by the primary battery unit and the switching unit controls the backup battery to cut out, the enable terminal of the control module outputs an enabling signal to control the charging chip to conduct and work normally. That is, the control module can detect the operating status of the switching unit, that is, the status of the primary / backup power switch, and then control the enabling and disabling of the charging chip according to the operating status of the switching unit.

[0108] It should be noted that in the prior art, it is necessary to increase the battery life of the backup battery. However, there is a discharge latent loop for the backup battery in the vehicle-mounted terminal. A latent loop is an unexpected signal transmission path that may cause circuit instability or interference. The latent loop may be caused by improper circuit design, wiring errors, or component failures. The discharge latent loop may cause an increase in signal transmission delay, signal distortion, or a decrease in circuit performance. The discharge latent loop of the backup battery may cause unexpected discharge of the backup battery and shorten the battery life of the backup battery.

[0109] However, in the primary / backup power switching circuit provided in this application, if the backup battery unit cuts in and the charging chip does not turn off, a discharge latent loop will occur. For example, as Figure 3 shown, the discharge latent loop is: backup battery unit → boost circuit → switching unit → power supply module → charging chip → backup battery unit. Therefore, in this application, the control module receives the status of the switching unit to control the charging chip. When the backup battery unit cuts in, the control module controls the charging chip to turn off, thereby turning off the discharge latent loop and extending the battery life.

[0110] In this embodiment, the output terminal of the primary battery unit is connected to the first input terminal of the switching unit; the output terminal of the backup battery unit is connected to the second input terminal of the switching unit through a boost circuit; the power output terminal of the switching unit is connected to the input terminal of the power supply module; the output terminal of the power supply module is respectively connected to the power supply terminal of the charging chip and the subsequent circuit; the signal output terminal of the switching unit is connected to the signal receiving terminal of the control module; the output terminal of the charging chip is connected to the input terminal of the backup battery unit; the enable terminal of the control module is connected to the control terminal of the charging chip; when the switching unit is powered by the backup battery unit, the enable terminal of the control module outputs a disabling signal; when the switching unit cuts out the backup battery, it can transmit the cut-out signal to the control module through its own signal output terminal; the control module can control the charging chip to stop working through its own enable terminal, avoiding the formation of a discharge latent loop and power consumption between the backup battery and the charging chip, and extending the battery life.

[0111] Optionally, the control terminal of the switching unit is connected to the control terminal of the control module.

[0112] That is to say, the switching unit is controlled by the control module. Specifically, the switching unit can control whether to switch in the backup battery unit according to the magnitude of the output voltage value of the primary battery unit, or can also control whether to switch in the backup battery unit according to the control signal of the control module. The control method controlled by the control signal of the control module and the control method controlled by the output voltage of the primary battery unit can be used independently or in combination, which is not specifically limited here and can be determined according to the actual situation, and all are within the protection scope of this application.

[0113] Specifically, the control module can detect the energy storage situation of the primary battery unit, receive the control signal of the upper computer, etc., and then send a corresponding control signal to the control terminal of the switching unit, and then control the switching unit to switch in the backup battery unit.

[0114] The switching unit can also receive the output voltage of the primary battery unit. When the output voltage of the primary battery unit is less than the threshold voltage, the switching unit switches in the backup battery unit.

[0115] The control signal output by the control terminal of the control module to the switching unit can configure the presence or absence of the signal according to the requirements of the application scenario, which will not be elaborated here one by one.

[0116] Normally, the switching unit can control the backup battery to cut out, and of course it can also be other situations, which will not be elaborated here one by one and can be determined according to the actual situation, and all are within the protection scope of this application.

[0117] Optionally, referring to Figure 4 , the switching unit includes: a detection unit (including D1, D2, R8, R9, R10, R11 and Q4 as shown in Figure 4 ) and a switching unit (including Q1, Q2, Q3, C1, C2, C3, R1, R2, R3, R4, R5, R6 and R7 as shown in Figure 4 ).

[0118] As shown in Figure 4 , MCU_PWRPASS: the control terminal of the control module, that is, the MCU transport mode control pin, which is pulled low during the transport mode and pulled high in other cases; UBPR_CUT: the voltage between the output voltage of the primary battery unit connected to the anode of the first diode D1 through the reverse protection unit, and this voltage value can be used to determine whether the primary battery unit loses power.

[0119] The detection unit can be used to detect whether a control signal sent by the control module is received, and to detect whether the output voltage of the primary battery unit is less than the threshold voltage. When the detection unit detects the control switching signal sent by the control module or the output voltage of the primary battery unit is less than the threshold voltage, it outputs a control signal to the switching unit, and the switching unit performs corresponding control actions.

[0120] The control signal sent by the control module can be a cut-out signal, that is, the switching unit cuts out the backup battery unit. When the output voltage of the primary battery unit is less than the threshold voltage, the switching unit cuts in the backup battery unit. Of course, the control signal sent by the control module can also be a cut-in signal. When the control signal is a cut-in signal, the backup battery unit can be cut in.

[0121] It should be noted that the cut-out signal sent by the control module and the output voltage of the primary battery unit being less than the threshold voltage will not exist simultaneously.

[0122] When the control module sends a cut-out signal, it is generally sent when the vehicle is in the transportation mode. When the vehicle is in the transportation mode, the output voltage of the primary battery unit will not be less than the threshold voltage.

[0123] The first input terminal of the detection unit receives the output signal of the primary battery unit.

[0124] Specifically, the first input terminal of the detection unit can be directly connected to the output terminal of the primary battery unit. Of course, it can also be connected to the output terminal of the primary battery unit through an anti-reverse unit. For example, the output terminal of the primary battery unit is connected to the input terminal of the anti-reverse unit; the output terminal of the anti-reverse unit is connected to the first output terminal of the detection unit.

[0125] The second input terminal of the detection unit serves as the control terminal of the switching unit.

[0126] Specifically, the second input terminal of the detection unit is connected to the control terminal of the control module and receives the control signal of the control module.

[0127] The output terminal of the detection unit is connected to the control terminal of the switching unit, and the connection point serves as the signal output terminal of the switching unit and is connected to the signal receiving terminal of the control module.

[0128] That is to say, the output signal of the detection unit can be used as the output signal of the switching unit and output to the signal receiving terminal of the control module.

[0129] The first input terminal of the switching unit serves as the first input terminal of the switching unit and is connected to the output terminal of the primary battery unit.

[0130] It should be noted that an anti - reverse unit, a voltage - stabilizing unit, a filtering unit, etc. can also be provided between the first input end of the switching unit and the output end of the primary battery unit. Specific limitations are not made here and it can be determined according to the actual situation, all of which are within the protection scope of this application.

[0131] The voltage received at the first input end of the switching unit can be the voltage after anti - reverse, voltage - stabilizing, and filtering of the output voltage of the primary battery unit. The voltage received at the first input end of the detection unit can be the voltage after anti - reverse of the output voltage of the primary battery unit. Of course, the voltage received at the first input end of the switching unit and the voltage received at the first input end of the detection unit can also be the same voltage. That is, after the first input ends of the switching unit and the detection unit are connected, they are directly or indirectly connected to the output end of the primary battery unit.

[0132] The second input end of the switching unit serves as the second input end of the switching unit and is connected to the output end of the backup battery unit through a boost circuit.

[0133] Specifically, the second input end of the switching unit is connected to the output end of the boost circuit; the input end of the boost circuit is connected to the output end of the backup battery unit.

[0134] The output end of the switching unit serves as the power output end of the switching unit and is connected to the input end of the power module.

[0135] Optionally, as Figure 4 shown, the switching unit includes: a first capacitor C1, a second capacitor C2, a third capacitor C3, a first switch tube Q1, a second switch tube Q2, a third switch tube Q3, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R, and a seventh resistor R7.

[0136] One end of the first switch tube Q1 is connected to one end of the first capacitor C1, and the connection point serves as the second input end of the switching unit and is connected to the output end of the backup battery unit through a boost circuit.

[0137] Specifically, one end of the first switch tube Q1 and one end of the first capacitor C1 are both connected to the output end of the boost circuit; the input end of the boost circuit is connected to the output end of the backup battery unit.

[0138] The second end of the first switch tube Q1 is respectively connected to the second end of the second switch tube Q2, one end of the first resistor R1, and one end of the second resistor R2.

[0139] The control end of the first switch tube Q1 is respectively connected to the other end of the first resistor R1 and one end of the third resistor R3.

[0140] The first end of the second switching transistor Q2 is respectively connected to one end of the second capacitor C2 and one end of the seventh resistor R7, and the connection point serves as the output end of the switching unit and is connected to the input end of the power supply module.

[0141] Specifically, the first end of the second switching transistor Q2, one end of the second capacitor C2, and one end of the seventh resistor R7 are all connected to the input end of the power supply module.

[0142] The control end of the second switching transistor Q2 is respectively connected to the other end of the second resistor R2 and one end of the fourth resistor R4.

[0143] The first switching transistor Q1 and the second switching transistor Q2 can be PMOS transistors. The first switching transistor Q1 and the second switching transistor Q2 are used to connect or disconnect the connection from the backup battery unit to the power supply module.

[0144] The other end of the third resistor R3 is respectively connected to the other end of the fourth resistor R4 and the first end of the third switching transistor Q3.

[0145] The control end of the third switching transistor Q3 is respectively connected to one end of the fifth resistor R5 and one end of the sixth resistor R.

[0146] The third switching transistor Q3 can be a triode.

[0147] When the third switching transistor Q3 is turned on, the third resistor R3 and the fourth resistor R4 are pulled to the ground GND. At this time, the gate-source voltage Vgs of the first switching transistor Q1 and the second switching transistor Q2 is less than the conduction voltage Vgs(th), and the first switching transistor Q1 and the second switching transistor Q2 are turned on. The output end of the backup battery unit supplies power to the power supply module through the discharge circuit; when the third switching transistor Q3 is turned off, there is no voltage drop across the first resistor R1 and the second resistor R2. At this time, the gate-source voltage Vgs of the first switching transistor Q1 and the second switching transistor Q2 is Vgs = 0 > Vgs(th), and the first switching transistor Q1 and the second switching transistor Q2 are turned off, and the discharge circuit of the backup battery unit is cut off.

[0148] The other end of the fifth resistor R5 serves as the control end of the switching unit and is respectively connected to the output end of the detection unit and the signal input end of the control module.

[0149] Specifically, the other end of the fifth resistor R5 is respectively connected to the second end of the fourth switching transistor Q4 in the detection unit and the signal input end of the control module.

[0150] The other end of the seventh resistor R7 is connected to one end of the third capacitor C3, and the connection point serves as the first input end of the switching unit and is directly or indirectly connected to the output end of the main battery unit.

[0151] Specifically, the other end of the seventh resistor R7 and one end of the third capacitor C3 are both directly or indirectly connected to the output terminal of the main battery unit. For example, the other end of the seventh resistor R7 and one end of the third capacitor C3 are both directly connected to the output terminal of the main battery unit, or the other end of the seventh resistor R7 and one end of the third capacitor C3 are both connected to the output terminal of the main battery unit through at least one of the reverse protection unit, the filtering unit, and the voltage stabilizing unit.

[0152] The other end of the first capacitor C1, the other end of the second capacitor C2, the other end of the third capacitor C3, the second end of the third switching transistor Q3, and the other end of the sixth resistor R are grounded to GND.

[0153] The first capacitor C1, the second capacitor C2, and the third capacitor C3 are used to achieve circuit protection and stabilize the voltages at the first input terminal, the second input terminal, and the output terminal of the switching unit.

[0154] Optionally, as Figure 4 shown, the detection unit includes: a first diode D1, a second diode D2, a fourth switching transistor Q4, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, and an eleventh resistor R11.

[0155] The anode of the first diode D1 serves as the first input terminal of the detection unit and is directly or indirectly connected to the output terminal of the main battery unit.

[0156] The cathode of the first diode D1 is connected to one end of the eleventh resistor R11.

[0157] The other end of the eleventh resistor R11 is respectively connected to one end of the tenth resistor R10 and the cathode of the second diode D2.

[0158] One end of the eighth resistor R8 serves as the second input terminal of the detection unit and is connected to the control terminal of the control module.

[0159] The other end of the eighth resistor R8 is respectively connected to the anode of the second diode D2, the control terminal of the fourth switching transistor Q4, and the first end of the fourth switching transistor Q4.

[0160] The first diode D1 and the second diode D2 are used to achieve circuit protection.

[0161] The fourth switching transistor Q4 can be a triode.

[0162] It should be noted that when the connection relationship between the control terminal of the control module and the control terminal of the switching unit is omitted, the eighth resistor R8 can be directly replaced by a pull-up power supply, or one end of the first resistor R1 is directly connected to the pull-up power supply. At this time, the switching unit is not controlled by the control module.

[0163] The other end of the tenth resistor R10 is grounded to GND.

[0164] The second terminal of the fourth switching transistor Q4 serves as the output terminal of the detection unit and is connected to one end of the fifth resistor R5 in the switching unit and the signal input terminal of the control module.

[0165] Now, the main and backup power switching process of the switching unit will be described:

[0166] (1) When the vehicle is operating normally, the control signal of the control module is pulled high. Under this condition, if the output voltage of the primary battery unit is lower than the threshold voltage, the vehicle terminal will normally switch to the mode powered by the backup battery unit.

[0167] Specifically, when the output voltage of the primary battery unit decreases to be less than the threshold voltage, the voltage division of the ninth resistor R9 will increase, and when the voltage division value of the ninth resistor R9 is greater than the conduction threshold of the fourth switching transistor Q4, the fourth switching transistor Q4 conducts; then, the voltage division value of the sixth resistor R also increases, and when the voltage division value of the sixth resistor R is greater than the conduction threshold of the third switching transistor Q3, the third switching transistor Q3 conducts; at this time, the gate levels of the first switching transistor Q1 and the second switching transistor Q2 are low, the first switching transistor Q1 and the second switching transistor Q2 are turned on, and the backup battery unit is switched in and starts to supply power.

[0168] When the output voltage of the primary battery unit resumes to be greater than the threshold voltage, the fourth switching transistor Q4 is turned off, and similarly, the third switching transistor Q3, the second switching transistor Q2, and the first switching transistor Q1 are also turned off. The backup battery unit is switched out, and the output voltage of the primary battery unit supplies power to the power module through the seventh resistor R7.

[0169] This threshold voltage can be a set critical voltage value, and its specific value is not elaborated here one by one. It can be determined according to the actual situation, and all are within the protection scope of this application.

[0170] The threshold voltage can be set by adjusting the voltage division ratios of the first diode D1, the second diode D2, the eighth resistor R8, the ninth resistor R9, the tenth resistor R10, and the eleventh resistor R11.

[0171] Specifically, assume that the voltage drops of the first diode D1 and the second diode D2 are both 0.4V, R11 = 47 kohm, R10 = 33 kohm, R9 = 47 kohm, R8 = 2 kohm; kohm is the unit of resistance ohm; the voltage at the control terminal of the control module or the corresponding pull-up power supply is 3.3V; the conduction voltage VBE of the fourth switching transistor Q4 is 0.6V. Then it can be calculated that when the output voltage of the primary battery unit is greater than 5.91V, the fourth switching transistor Q4 is turned off, the backup battery unit is switched out and does not work; when the output voltage of the primary battery unit is less than 5.91V, the fourth switching transistor Q4 conducts, and the backup battery is switched in and starts to supply power.

[0172] Therefore, the threshold voltage can be set to 5.91V. Of course, the threshold voltage can also be determined according to the actual device type and circuit structure adopted. Details are not elaborated here one by one. It depends on the actual situation, and all are within the protection scope of the application.

[0173] (2) When the vehicle is in the transportation mode, the control signal of the control module is pulled low. The fourth switch Q4 and the third switch Q3 in the switching unit are in the off state, and the first switch Q1 and the second switch Q2 are also in the off state. However, there will be a weak leakage current in the freewheeling diodes built in the first switch Q1 and the second switch Q2, which can be regarded as the normal leakage current of the backup battery unit and the BOOST boost circuit; the backup battery unit is cut out, and the backup battery unit will not discharge to the subsequent circuit through the discharge loop in this mode. Therefore, even after the vehicle-mounted terminal exits the transportation mode, the backup battery unit still has sufficient power and will not be over-discharged to damage the battery.

[0174] The transportation mode can be understood as: the vehicle-mounted terminal is in the shutdown state, and the backup battery unit of the vehicle-mounted terminal will not discharge in the transportation mode.

[0175] (3) When the backup battery unit is used for power supply, if the backup battery unit is over-discharged, the control module cannot work properly, and the discharge loop of the backup battery unit is cut off, that is, the backup battery unit will not discharge to the subsequent circuit through the discharge loop, realizing the protection of the backup battery.

[0176] It should be noted that in the existing main-backup power switching technology, a self-built switch circuit is usually adopted between the output end of the main battery and the input end of the power module, resulting in a high cost; while in this application, only the seventh resistor R7 is used between the output end of the main battery unit and the power module, avoiding increasing the cost of the main-backup power switching circuit.

[0177] Optionally, see Figure 5 It further includes: a driving unit (including R12, R13, R14, R15, R16 and Q5 as shown in Figure 5 ).

[0178] The first end of the driving unit is connected to the signal output end of the switching unit.

[0179] The second end of the driving unit is connected to the enable end of the control module.

[0180] The third end of the driving unit is connected to the control end of the charging chip.

[0181] When the control module is an MCU, the enable end of the MCU can send a PWM signal to the charging chip to control the on and off of the charging chip.

[0182] It should be noted that the charging chip can also be controlled independently by the driving unit; that is, the charging chip is controlled by a pure hardware circuit; the charging chip can also be controlled independently by the MCU, such as the charging chip is controlled by pure software; it can also be a control method combining the driving unit and the MCU, that is, a control method combining software and hardware.

[0183] That is, the first end of the driving unit receives the signal of the switching unit and controls the on / off of the charging chip through the third end of the driving unit.

[0184] Optionally, referring to Figure 5 , the driving unit includes: the twelfth resistor R12, the thirteenth resistor R13, the fourteenth resistor R14, the fifteenth resistor R15, the sixteenth resistor R16 and the fifth switching transistor Q5.

[0185] One end of the twelfth resistor R12 serves as the first end of the driving unit and is connected to the signal output end of the switching unit.

[0186] Specifically, the connection point between the fifth resistor R5 and the fourth switching transistor Q4 in the switching unit is connected to one end of the twelfth resistor R12.

[0187] The other end of the twelfth resistor R12 is respectively connected to the control end of the fifth switching transistor Q5 and one end of the thirteenth resistor R13.

[0188] The first end of the fifth switching transistor Q5 is connected to one end of the fifteenth resistor R15.

[0189] The other end of the fifteenth resistor R15 is respectively connected to one end of the fourteenth resistor R14 and one end of the sixteenth resistor R16, and the connection point serves as the third end of the driving unit and is connected to the control end of the charging chip.

[0190] The other end of the sixteenth resistor R16 serves as the second end of the driving unit and is connected to the enable end of the control module.

[0191] The other end of the thirteenth resistor R13, the second end of the fifth switching transistor Q5, and the other end of the fourteenth resistor R14 are all grounded to GND.

[0192] It should be noted that when the driving unit independently controls the charging chip, a pull-up power supply can be connected to the other end of the sixteenth resistor R16, and the enable signal is provided by the pull-up power supply. When the driving unit receives the switching signal, the fifth switching transistor Q5 conducts, pulling down the control end of the charging chip to the ground to control the charging chip to turn off.

[0193] Specifically, when the backup battery unit is switched in, the fourth switching transistor Q4 in the switching unit is turned on while the signal output terminal of the switching unit is pulled high, the voltage division value of the thirteenth resistor R13 increases, and when the voltage division value of the thirteenth resistor R13 is greater than the conduction threshold of the fifth switching transistor Q5, the fifth switching transistor Q5 conducts, the control terminal of the charging chip is pulled low, and the charging chip is turned off, avoiding the situation that the backup battery charges itself, and improving the battery life of the backup battery.

[0194] At the same time, when the signal receiving end of the control module monitors that the signal output terminal of the switching unit is set high, it is determined that the vehicle-mounted terminal is in the state of being powered by the backup battery unit, then the control module turns off unnecessary devices in the subsequent circuit, saves the power of the backup battery unit, and at the same time stops outputting the PWM signal to the charging chip.

[0195] To enable the fourth switching transistor Q4 to be capable of pulling up the third switching transistor Q3 and the fifth switching transistor Q5 simultaneously, the collector current Ic of the fourth switching transistor Q4 is made greater than the sum of the turn-on currents of the bases of the third switching transistor Q3 and the fifth switching transistor Q5. Accordingly, the resistance values of the fifth resistor R5, the sixth resistor R, the twelfth resistor R12, and the thirteenth resistor R13 need to be appropriately adjusted. If the saturation voltage drop VCEsat of the fourth switching transistor Q4 is 0.25V, R8 = 2kohm, R5 = R12 = 43kohm, R6 = R13 = 100kohm, the MCU_PWRPASS voltage is 3.3V, the base-emitter conduction voltage VBE of the third switching transistor Q3 and the fifth switching transistor Q5 is 0.66V, and the base turn-on current IBsat is 0.01mA, then the base voltage VB of the third switching transistor Q3 and the fifth switching transistor Q5 can be calculated as VB = 2.07V > VBE = 0.66V, and the drive current is greater than 2 times IBsat, which can drive the third switching transistor Q3 and the fifth switching transistor Q5 simultaneously.

[0196] When the backup battery unit is switched out, the fourth switching transistor Q4 in the switching unit is turned off while the signal output terminal of the switching unit is pulled low, the voltage division value of the thirteenth resistor R13 decreases, and when the voltage division value of the thirteenth resistor R13 is less than the conduction threshold of the fifth switching transistor Q5, the fifth switching transistor Q5 is turned off, the control terminal of the charging chip is pulled high, and the charging chip conducts. At the same time, when the signal receiving end of the control module monitors that the signal output terminal of the switching unit is pulled down to the ground, the control module determines that the vehicle-mounted terminal is in the state of being powered by the main battery unit, and the control module continuously outputs the PWM signal to the charging chip to control the charging chip to charge the backup battery unit and replenish the power of the backup battery unit.

[0197] In this embodiment, by monitoring the main and backup power states through software, the software can control the connection of the backup battery unit and the backup power charging, strengthening the management of the backup battery unit.

[0198] Optionally, it further includes a detection unit.

[0199] The detection unit is used to detect the information of the main and standby power switching circuit and transmit it to the control module; the information of the main and standby power switching circuit includes: the temperature of the standby battery unit, the output voltage and output current of the charging chip.

[0200] Specifically, for the temperature of the standby battery unit, a temperature sensor can be used to collect the temperature of the standby battery unit. For the output voltage of the charging chip, one end of a voltage dividing circuit can be connected to the output end of the charging chip, and the other end of the voltage dividing circuit can be connected to the voltage pin of the control module to achieve the collection of the output voltage of the charging chip. Of course, a voltage sensor can also be used to collect the output voltage of the charging chip and then transmit it to the control module. For the output current of the charging chip, it can also be collected by a current sensor; the specific collection and detection methods are not elaborated here one by one and can be determined according to the actual situation, all within the protection scope of this application.

[0201] Therefore, the control module can collect the output voltage, current and temperature information of the main battery unit and the standby battery unit, and output a PWM signal to control the enabling of the charging chip.

[0202] The process of the control module outputting a PWM signal to control the charging chip can be: the control module outputs a PWM signal to the control end of the charging chip, that is, the enabling pin of the charging chip, to control and adjust the output current of the charging chip. If the enabling pin of the charging chip receives a high level, the output current of the charging chip reaches the set current value; if the enabling pin of the charging chip receives a low level, the output current of the charging chip is zero.

[0203] The features described in each embodiment of this specification can be replaced or combined with each other. For the same or similar parts between each embodiment, reference can be made to each other. Each embodiment focuses on the differences from other embodiments. In particular, for the system or system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can refer to the partial description of the method embodiment. The systems and system embodiments described above are only illustrative. The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they can be located in one place or distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. Those of ordinary skill in the art can understand and implement it without creative work.

[0204] Those skilled in the art may further realize that the units and algorithm steps of each example described in connection with the embodiments disclosed herein can be implemented by electronic hardware, computer software, or a combination of the two. To clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described according to functions in the above description. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present utility model.

[0205] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present utility model. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present utility model. Therefore, the present utility model will not be limited to these embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A main and standby power switching circuit, characterized in that, Comprising: A main battery unit, a backup battery unit, a switching unit, a boost circuit, a power module, a charging chip, and a control module; The output terminal of the main battery unit is connected to the first input terminal of the switching unit; The output terminal of the backup battery unit is connected to the second input terminal of the switching unit through the boost circuit; The power output terminal of the switching unit is connected to the input terminal of the power module; The output terminal of the power module is respectively connected to the power supply terminal of the charging chip and the subsequent circuit; The signal output terminal of the switching unit is connected to the signal receiving terminal of the control module; The output terminal of the charging chip is connected to the input terminal of the backup battery unit; The enable terminal of the control module is connected to the control terminal of the charging chip; when the switching unit is powered by the backup battery unit, the enable terminal of the control module outputs a disabling signal.

2. The main and backup power switching circuit according to claim 1, wherein The control terminal of the switching unit is connected to the control terminal of the control module.

3. The main and backup power switching circuit according to claim 2, wherein The switching unit includes: a detection unit and a switching unit; The first input terminal of the detection unit receives the output signal of the main battery unit; The second input terminal of the detection unit serves as the control terminal of the switching unit; The output terminal of the detection unit is connected to the control terminal of the switching unit, and the connection point serves as the signal output terminal of the switching unit; The first input terminal of the switching unit serves as the first input terminal of the switching unit; The second input terminal of the switching unit serves as the second input terminal of the switching unit; The output terminal of the switching unit serves as the power output terminal of the switching unit.

4. The main and standby power switching circuit according to claim 3, wherein The switching unit includes: a first capacitor, a second capacitor, a third capacitor, a first switching tube, a second switching tube, a third switching tube, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, and a seventh resistor; One end of the first switching tube and one end of the first capacitor are connected, and the connection point serves as the second input terminal of the switching unit; The second end of the first switching tube is respectively connected to the second end of the second switching tube, one end of the first resistor, and one end of the second resistor; The control terminal of the first switching tube is respectively connected to the other end of the first resistor and one end of the third resistor; One end of the second switching tube is respectively connected to one end of the second capacitor and one end of the seventh resistor, and the connection point serves as the output terminal of the switching unit; The control terminal of the second switching tube is respectively connected to the other end of the second resistor and one end of the fourth resistor; The other end of the third resistor is respectively connected to the other end of the fourth resistor and the first end of the third switching tube; The control terminal of the third switching tube is respectively connected to one end of the fifth resistor and one end of the sixth resistor; The other end of the fifth resistor serves as the control terminal of the switching unit; The other end of the seventh resistor is connected to one end of the third capacitor, and the connection point serves as the first input terminal of the switching unit; The other end of the first capacitor, the other end of the second capacitor, the other end of the third capacitor, the second end of the third switching tube, and the other end of the sixth resistor are grounded.

5. The main and backup power switching circuit according to claim 3, wherein The detection unit includes: a first diode, a second diode, a fourth switching transistor, an eighth resistor, a ninth resistor, a tenth resistor, and an eleventh resistor; The anode of the first diode serves as the first input terminal of the detection unit; The cathode of the first diode is connected to one end of the eleventh resistor; The other end of the eleventh resistor is respectively connected to one end of the tenth resistor and the cathode of the second diode; One end of the eighth resistor serves as the second input terminal of the detection unit; The other end of the eighth resistor is respectively connected to the anode of the second diode, the control terminal of the fourth switching transistor, and the first end of the fourth switching transistor; The other end of the tenth resistor is grounded; The second end of the fourth switching transistor serves as the output terminal of the detection unit.

6. The main and standby power switching circuit according to claim 1, characterized in that, It further includes: A driving unit; The first end of the driving unit is connected to the signal output terminal of the switching unit; The second end of the driving unit is connected to the enable terminal of the control module; The third end of the driving unit is connected to the control terminal of the charging chip.

7. The main and standby power switching circuit according to claim 6, wherein The driving unit includes: a twelfth resistor, a thirteenth resistor, a fourteenth resistor, a fifteenth resistor, a sixteenth resistor, and a fifth switching transistor; One end of the twelfth resistor serves as the first end of the driving unit; The other end of the twelfth resistor is respectively connected to the control terminal of the fifth switching transistor and one end of the thirteenth resistor; The first end of the fifth switching transistor is connected to one end of the fifteenth resistor; The other end of the fifteenth resistor is respectively connected to one end of the fourteenth resistor and one end of the sixteenth resistor, and the connection point serves as the third end of the driving unit; The other end of the sixteenth resistor serves as the second end of the driving unit; The other end of the thirteenth resistor, the second end of the fifth switching transistor, and the other end of the fourteenth resistor are all grounded.

8. The main and backup power switching circuit according to claim 1, characterized in that, It further includes: An anti-reverse unit; The anti-reverse unit is disposed between the main battery unit and the switching unit.

9. The main and backup power switching circuit according to claim 1, wherein It further includes: A voltage stabilizing unit and a filtering unit; The voltage stabilizing unit and the filtering unit are disposed between the main battery unit and the switching unit.

10. The main and backup power switching circuit according to claim 1, characterized in that It further includes a detection unit; The detection unit is configured to detect information of the main and backup power switching circuit and transmit it to the control module; Wherein the information of the main and backup power switching circuit includes: the temperature of the backup battery unit, the output voltage and output current of the charging chip.

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