Circuit and device for VBAT voltage detection protection

Abstract

The invention discloses a circuit and device for VBAT voltage detection protection, and relates to the field of circuit design. The circuit comprises a power switch module which is used for controlling the power output of the battery simulator to the VBAT; the anomaly detection module detects a voltage signal of the VBAT in real time, compares the voltage signal with a threshold voltage, generates a voltage detection signal and transmits the voltage detection signal to the state latch module; the state latch module is used for generating a state latch signal according to the voltage detection signal, transmitting the state latch signal to the switch switching module, keeping the state latch signal unchanged when the VBAT is in overvoltage, and releasing latch until a reset signal is received; and the switch switching module is used for controlling the power switch module to be switched off and switched on according to the state latch signal so as to control whether the battery simulator supplies power to the VBAT or not. The circuit can rapidly cut off the power supply at the moment of VBAT overvoltage, thereby effectively preventing the main circuit board from being damaged due to overvoltage, and improving the testing safety and reliability of the mainboard.

Description

Technical Field

[0001] The present invention relates to the technical field of circuit design, and in particular to a circuit and a device for VBAT voltage detection protection. Background Art

[0002] In the manufacturing and testing process of consumer electronic products, functional testing of the main circuit board is an important step to ensure stable product performance. Usually during testing, a battery simulator (Battery Simulator) is used to provide the main circuit board with a battery voltage (VBAT). However, in actual operation, incorrect wiring of the battery simulator or device failure may cause the VBAT output voltage to increase abnormally or become uncontrolled. In this case, the main circuit board is easily damaged by overvoltage, which may affect the function of the mainboard at the least or burn out at the worst, thereby increasing production costs, reducing test efficiency, and even affecting the product development progress.

[0003] Although the existing motherboard function test equipment has basic voltage protection functions, its circuit response speed is usually slow and it is unable to quickly cut off the power supply at the moment of voltage abnormality, resulting in the motherboard still being at risk of burning due to the power protection mechanism not being triggered in time. In addition, the existing VBAT voltage protection circuit cannot realize the locking function of the abnormal state. When an abnormality occurs, the circuit will try to automatically restore the power supply, causing repeated power-on when the problem is not completely solved, further increasing the risk of motherboard damage. Therefore, it is particularly important in the art to design a VBAT voltage detection protection circuit with fast response and protection locking functions. Summary of the invention

[0004] The purpose of the present invention is to provide a circuit and device for VBAT voltage detection protection, which can cut off the power supply in time when the VBAT is over-voltage, and maintain the latched state before the fault is eliminated, so as to realize real-time monitoring of the voltage and rapid response protection.

[0005] To achieve the above object, the present invention discloses the following technical solution:

[0006] A first aspect of the present invention provides a circuit for VBAT voltage detection protection, comprising a power switch module, an abnormality detection module, a state latch module and a switch switching module; wherein:

[0007] The power switch module is connected to the battery simulator, and is used to control the power output of the battery simulator to VBAT, and disconnect the power supply of the battery simulator to VBAT when VBAT is over-voltage, so as to perform over-voltage protection;

[0008] The abnormality detection module is connected to the power switch module, and is used to detect the voltage signal of VBAT in real time, and compare the voltage signal with a set threshold voltage, generate a voltage detection signal and transmit it to the state latch module;

[0009] The state latch module is connected to the abnormality detection module, and is used to generate a state latch signal according to the voltage detection signal and transmit it to the switch switching module, and keep the current state latch signal unchanged when VBAT overvoltage is detected until the signal latch is released after receiving a reset signal;

[0010] The switch switching module is connected to the state latch module and the power switch module respectively, and is used to control the disconnection and conduction of the power switch module according to the state latch signal, so as to control whether the battery simulator supplies power to VBAT.

[0011] In the above-mentioned circuit for VBAT voltage detection protection, when the circuit is working normally, the power switch module is in the on state, and the battery simulator provides power output to VBAT; the abnormality detection module monitors the voltage signal of VBAT in real time, and if the VBAT voltage is within the preset threshold voltage range, generates a voltage detection signal and transmits it to the state latch module; the state latch module is in the unlocked state, and generates a state latch signal and transmits it to the switch switching module; after receiving the state latch signal, the switch switching module controls the circuit switch module to remain in the on state, and the battery simulator continues to supply power to VBAT;

[0012] When VBAT is over-voltage, if the abnormality detection module detects that the VBAT voltage exceeds the preset threshold voltage range, it generates an over-voltage detection signal and transmits it to the status latch module; the status latch module generates a status latch signal based on the over-voltage detection signal and keeps the status latch signal unchanged; after receiving the status latch signal, the switch switching module controls the power switch module to disconnect, thereby cutting off the power supply of the battery simulator to VBAT.

[0013] Optionally, in the above-mentioned circuit for VBAT voltage detection protection, the power switch module includes a light emitting diode LED2, a fifteenth resistor R15, a sixteenth resistor R16 and a solid-state relay U9;

[0014] The first input end of the solid-state relay U9 is connected to the first voltage through the sixteenth resistor R16, and the first voltage is also connected to the second input end of the solid-state relay U9 through the fifteenth resistor R15 and the light-emitting diode LED2 in sequence; the first output end of the solid-state relay U9 is connected to the abnormality detection module and connected to VBAT, and the second output end of the solid-state relay U9 is connected to the battery simulator;

[0015] During normal operation, the solid-state relay U9 is in a closed state, and the battery simulator supplies power to VBAT; when VBAT is over-voltage, the solid-state relay U9 is controlled to be disconnected, cutting off the power supply of the battery simulator to VBAT.

[0016] Optionally, in the above-mentioned circuit for VBAT voltage detection protection, the abnormality detection module includes a window comparator U10, an eighth capacitor C8, a seventeenth resistor R17, an eighteenth resistor R18 and a nineteenth resistor R19, and the seventeenth resistor R17, the eighteenth resistor R18 and the nineteenth resistor R19 constitute a voltage divider network;

[0017] The window comparator U10 includes a first comparator CMP1, a second comparator CMP2 and a reference voltage source; one end of the seventeenth resistor R17 is connected to VBAT, and the other end is connected to one end of the eighteenth resistor R18 and connected to the positive input terminal INA of the first comparator CMP1; the other end of the eighteenth resistor R18 is connected to one end of the nineteenth resistor R19 and connected to the inverting input terminal INB of the second comparator CMP2, and the other end of the nineteenth resistor R19 is grounded; the inverting input terminal of the first comparator CMP1 is connected to the positive input terminal of the second comparator CMP2 and is grounded through the reference voltage source; the output terminal OUTA of the first comparator CMP1 is connected to the output terminal OUTB of the second comparator CMP2 and outputs a signal to the state latch module; the power supply terminal of the window comparator U10 is connected to the second voltage, and its power supply terminal is also grounded through the eighth capacitor C8.

[0018] Furthermore, the threshold voltage includes a high voltage threshold V H and low voltage threshold V L , the resistance values ​​of each resistor in the voltage divider network are set as follows:

[0019] R total =R17+R18+R19=V H / I max , where R total is the total resistance, I max is the maximum current in the voltage divider network;

[0020] R19=V REF / I max , where V REF A reference voltage provided by the reference voltage source;

[0021] R18=(R total / V L )×V REF -R19;

[0022] R17=R total -(R18+R19);

[0023] In the formula, R17, R18 and R19 are the resistance values ​​of the seventeenth resistor, the eighteenth resistor and the nineteenth resistor respectively.

[0024] In the above-mentioned circuit for VBAT voltage detection protection, the first comparator CMP1 is used to detect whether the voltage of its positive input terminal INA is higher than the high voltage threshold V H , and when higher than the high voltage threshold V H When the voltage at the inverting input terminal INB is lower than the low voltage threshold V L , and when it falls below the low voltage threshold V L When the overvoltage detection signal is low, it outputs a low level.

[0025] Optionally, in the above-mentioned circuit for VBAT voltage detection protection, a level conversion module is further provided between the abnormality detection module and the state latch module, and the level conversion module includes an NPN switch tube Q1, a thirteenth resistor R13 and a fourteenth resistor R14;

[0026] The base of the switch tube Q1 is connected to the output end of the window comparator U10, and is connected to the second voltage through the fourteenth resistor R14; the second voltage is also connected to the collector of the switch tube Q1 through the thirteenth resistor R13, and the collector of the switch tube Q1 is also connected to the state latch module; the emitter of the switch tube Q1 is grounded.

[0027] When the window comparator U10 outputs a high-level voltage detection signal, the switch tube Q1 is turned on and outputs a low-level voltage conversion signal to the state latch module; when the window comparator U10 outputs a low-level overvoltage detection signal, the switch tube Q1 is turned off and outputs a high-level overvoltage conversion signal to the state latch module.

[0028] Optionally, in the above-mentioned circuit for VBAT voltage detection protection, the state latch module includes a twelfth resistor R12 and an RS latch U7;

[0029] The collector of the switch tube Q1 is connected to the set end of the RS latch U7 through the twelfth resistor R12; the reset end of the RS latch is connected to the PC host computer to receive a reset signal; the output end of the RS latch U7 is connected to the switch switching module; the power supply end of the RS latch U7 is connected to the first voltage;

[0030] The RS latch U7 generates a corresponding state latch signal according to the voltage conversion signal or overvoltage conversion signal input thereto and transmits it to the switch switching module. When VBAT is overvoltage, the RS latch U7 generates a high-level state latch signal according to the high-level overvoltage detection signal and keeps the high-level state latch signal unchanged until the reset signal sent by the PC host computer is received and the latch is released.

[0031] Optionally, in the above-mentioned circuit for VBAT voltage detection protection, the switch switching module includes a sixth capacitor C6, a seventh capacitor C7 and an analog switch chip U8;

[0032] The output end of the RS latch U7 is connected to the enable end of the analog switch chip U8; the first input end of the analog switch chip U8 is connected to the first voltage, and its first input end is also grounded through the seventh capacitor C7; the second input end of the analog switch chip U8 is grounded; the output end of the analog switch chip U8 is connected to the second input end of the solid-state relay U9; the power supply end of the analog switch chip U8 is connected to the first voltage, and its power supply end is also grounded through the sixth capacitor C6;

[0033] The analog switch chip U8 controls the on and off of the solid-state relay U9 according to the state latch signal of its enable terminal to control the power output of the battery simulator, and when the state latch signal is at a high level, the solid-state relay U9 is disconnected, cutting off the battery simulator from supplying power to VBAT.

[0034] A second aspect of the present invention provides a device for VBAT voltage detection and protection, the device comprising the circuit for VBAT voltage detection and protection as described in the first aspect.

[0035] The effects provided in the content of the invention are only the effects of the embodiments, not all the effects of the invention. One of the above technical solutions has the following advantages or beneficial effects:

[0036] The present application provides a circuit and device for VBAT voltage detection protection, and the circuit includes a power switch module, an abnormality detection module, a state latch module and a switch switching module. The power switch module is connected to a battery simulator to control the power output of the battery simulator to VBAT; the abnormality detection module detects the voltage signal of VBAT in real time, compares the voltage signal with the threshold voltage, generates a voltage detection signal and transmits it to the state latch module; the state latch module generates a state latch signal according to the voltage detection signal and transmits it to the switch switching module, and keeps the state latch signal unchanged when VBAT is overvoltage until the reset signal is received and the latch is released; the switch switching module controls the power switch module to disconnect and conduct according to the state latch signal to control whether the battery simulator supplies power to VBAT. This circuit can quickly cut off the power supply when VBAT is overvoltage, and lock the overvoltage state through the state latch function until the fault is eliminated, avoiding repeated power-on before the fault is eliminated, thereby effectively protecting the device under test, reducing the risk of equipment damage in the motherboard function test, and improving the stability and reliability of the test process. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0038] Figure 1 A schematic diagram of a circuit structure for VBAT voltage detection protection according to an embodiment of the present application;

[0039] Figure 2 A circuit schematic diagram for VBAT voltage detection protection according to an embodiment of the present application;

[0040] Reference numerals:

[0041] 110 - power switch module, 120 - abnormality detection module, 130 - state latch module, 140 - switch switching module, 150 - level conversion module. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0043] It should be noted that references to "one embodiment", "embodiment", "example embodiment", etc. in this specification refer to the embodiment being described which may include specific features, structures or characteristics, but not every embodiment must include these specific features, structures or characteristics. In addition, such expressions do not refer to the same embodiment. Furthermore, when describing specific features, structures or characteristics in conjunction with an embodiment, whether or not there is an explicit description, it is indicated that incorporating such features, structures or characteristics into other embodiments is within the knowledge of those skilled in the art.

[0044] As described in the background technology, in the main circuit board function test, when the battery simulator has a wiring error or equipment failure, the VBAT voltage will cause an abnormal increase, which can easily cause overvoltage damage to the mainboard, affecting the normal use and development progress of the product. Although the prior art provides basic voltage protection functions, the response speed is slow, and the abnormal state cannot be effectively locked, resulting in repeated power supply when the fault is not eliminated, increasing the risk of damage. Based on this, an embodiment of the present application provides a circuit and device for VBAT voltage detection protection, which can immediately cut off the power supply when the VBAT overvoltage is detected, and maintain a latched state before the fault is eliminated, so as to achieve real-time monitoring of the voltage and rapid response protection.

[0045] refer to Figure 1 , Figure 1 FIG. 1 is a schematic diagram showing a circuit structure for VBAT voltage detection protection according to an embodiment of the present application. Figure 1 As shown, the circuit includes a power switch module 110, an abnormality detection module 120, a state latch module 130 and a switch switching module 140. The power switch module 110 is connected to the battery simulator to control the power output of the battery simulator to VBAT, and disconnects the power supply of the battery simulator 110 to VBAT when VBAT is overvoltage, so as to perform VBAT overvoltage protection. The abnormality detection module 120 is connected to the power switch module 110 to detect the voltage signal of VBAT in real time, and compare the detected voltage signal with the set threshold voltage, generate a voltage detection signal and transmit it to the state latch module 130. The state latch module 130 is connected to the abnormality detection module 120 to generate a state latch signal according to the voltage detection signal and transmit it to the switch switching module 140, and keep the current state latch signal unchanged when VBAT overvoltage is detected until the signal latch is released after receiving a reset signal. The switch switching module 140 is connected to the state latch module 130 and the power switch module 110 respectively, and is used to control the disconnection and conduction of the power switch module 110 according to the state latch signal, thereby controlling the power supply of the battery simulator to VBAT.

[0046] When the circuit is operating normally, the power switch module 110 is connected to the battery simulator, allowing the battery simulator to provide a stable power output to VBAT. At the same time, the abnormality detection module 120 continuously monitors the voltage signal of VBAT, collects and compares the voltage with the preset threshold voltage in real time, and generates a voltage detection signal to transmit to the state latch module 130. If the VBAT voltage remains within the safety threshold range, the state latch module 130 is in an unlocked state, the switch switching module 130 controls the circuit switch module 110 to be in an on state, and the battery simulator normally supplies power to VBAT to ensure the normal operation of the device under test (DUT).

[0047] When VBAT is over-voltage, if the abnormality detection module 120 detects that the VBAT voltage exceeds the preset threshold voltage, an over-voltage detection signal is immediately generated and transmitted to the state latch module 130. At this time, the state latch module 130 responds to the over-voltage detection signal, generates a state latch signal and keeps the state latch signal unchanged, latching the current state. After the switch switching module 140 receives the state latch signal, it controls the power switch module 110 to quickly cut off the power supply of the battery simulator to VBAT, realizes VBAT over-voltage protection, and prevents damage to the device under test. After controlling the power switch module 110 to cut off the power supply of the battery simulator to VBAT, the technician can eliminate the cause of the voltage abnormality, and after confirming that the fault has been resolved, send a reset signal to the state latch module 130 through the PC host computer. After receiving the reset signal, the state latch module 130 releases the latch state.

[0048] Therefore, the circuit of this embodiment can quickly cut off the power supply when VBAT is over-voltage, and lock the state through the state latch function to avoid repeated power-on before the fault is eliminated, thereby effectively protecting the device under test. This design improves the overvoltage protection effect in the motherboard function test, reduces the risk of equipment damage, and improves the stability and overall efficiency of the test process.

[0049] Figure 2 A circuit schematic diagram for VBAT voltage detection protection according to an embodiment of the present application is shown. Figure 2As shown, in this embodiment, the power switch module 110 includes a light-emitting diode LED2, a fifteenth resistor R15, a sixteenth resistor R16 and a solid-state relay U9. Among them, the first input end of the solid-state relay U9 is connected to the first voltage (5V power supply voltage) through the sixteenth resistor R16, and the first voltage is also connected to the second input end of the solid-state relay U9 through the fifteenth resistor R15 and the light-emitting diode LED2 in sequence; the first output end of the solid-state relay U9 is connected to the abnormality detection module 120 and connected to VBAT, and the second output end of the solid-state relay U9 is connected to the battery simulator. When the circuit is working normally, the solid-state relay U9 is in a closed state, and the light-emitting diode LED2 emits light to indicate the current power supply state. At this time, the battery simulator provides power to VBAT; when VBAT is over-voltage, the solid-state relay U9 is controlled to disconnect, and the battery simulator is cut off from the power supply to VBAT. Through the fast response characteristics of the solid-state relay U9, the power supply can be quickly cut off when VBAT is over-voltage, so as to avoid damage to the main circuit board due to over-voltage and protect the safety of the mainboard.

[0050] In some embodiments, the abnormality detection module 120 includes a window comparator U10, an eighth capacitor C8, a seventeenth resistor R17, an eighteenth resistor R18 and a nineteenth resistor R19, and the seventeenth resistor R17, the eighteenth resistor R18 and the nineteenth resistor R19 form a voltage divider network. The window comparator U10 includes a first comparator CMP1, a second comparator CMP2 and a reference voltage source; one end of the seventeenth resistor R17 is connected to VBAT, and the other end is connected to one end of the eighteenth resistor R18 and connected to the positive input end of the first comparator CMP1; the other end of the eighteenth resistor R18 is connected to one end of the nineteenth resistor R19 and connected to the reverse input end INB of the second comparator CMP2, and the other end of the nineteenth resistor R19 is grounded. The reverse input end of the first comparator CMP1 is connected to the positive input end of the second comparator CMP2 and is grounded through the reference voltage source; the output end of the first comparator CMP1 is connected to the output end of the second comparator CMP2 and connected to the state latch module 130. The power supply terminal of the window comparator U10 is connected to the second voltage (3.3V power supply voltage), and the power supply terminal is also grounded through the eighth capacitor C8 to provide a stable operating voltage.

[0051] Specifically, the threshold voltage includes a high voltage threshold V H and low voltage threshold V L , the resistance values ​​of each resistor in the voltage divider network are set as follows:

[0052] R total =R17+R18+R19=V H / I max , where R total is the total resistance, I maxis the maximum current in the voltage divider network, which can be set to 10μA, for example;

[0053] R19=V REF / I max , where V REF The reference voltage provided by the reference voltage source may be set to 400 mV, for example;

[0054] R18=(R total / V L )×V REF -R19;

[0055] R17=R total -(R18+R19);

[0056] In the formula, R17, R18 and R19 are the resistance values ​​of the seventeenth resistor, the eighteenth resistor and the nineteenth resistor respectively.

[0057] In this embodiment, the abnormality detection module 120 monitors and judges the input voltage VBAT in real time based on the window comparator U10 to ensure that it is within the high voltage threshold V H and low voltage threshold V L The seventeenth resistor R17, the eighteenth resistor R18 and the nineteenth resistor R19 are connected between VBAT and the ground terminal to divide the voltage of VBAT and convert it into a suitable voltage signal for comparison. The reference voltage source in the window comparator U10 can provide a stable reference voltage V REF The first comparator CMP1 detects whether the voltage at its positive input terminal INA is higher than the high voltage threshold V H , and when higher than the high voltage threshold V H The second comparator CMP2 detects whether the voltage at its inverting input terminal INB is lower than the low voltage threshold V L , and when it falls below the low voltage threshold V L When the overvoltage detection signal is low, the overvoltage detection signal is also output. The low-level overvoltage detection signal is transmitted to the state latch module as an abnormal detection signal, thereby triggering subsequent protection actions.

[0058] In some embodiments, a level conversion module 150 is further provided between the abnormality detection module 120 and the state latch module 130 for performing level conversion and reliable transmission of signals. The level conversion module 150 includes a switch tube Q1, a thirteenth resistor R13, and a fourteenth resistor R14. Among them, the switch tube Q1 can be selected as an NPN transistor, the base of the switch tube Q1 is connected to the output end of the window comparator U10, and is connected to the second voltage through the fourteenth resistor R14; the second voltage is also connected to the collector of the switch tube Q1 through the thirteenth resistor R13, and the collector of the switch tube Q1 is also connected to the state latch module 130; the emitter of the switch tube Q1 is grounded. When the window comparator U10 outputs a high-level voltage detection signal, the switch tube Q1 is turned on, and the collector voltage of the switch tube Q1 is close to the ground potential (low level), so a low-level voltage conversion signal is output to the state latch module 130; when the window comparator U10 outputs a low-level overvoltage detection signal, the switch tube Q1 is turned off, and the collector of the switch tube Q1 is connected to the second voltage through the thirteenth resistor R13, so a high-level overvoltage conversion signal is output to the state latch module 130, thereby providing isolation and conversion between the input signal and the output signal, ensuring the reliability and accuracy of signal transmission.

[0059] In some embodiments, the state latch module 130 includes a twelfth resistor R12 and an RS latch U7. Among them, the collector of the switch tube Q1 is connected to the set end of the RS latch U7 through the twelfth resistor R12; the reset end of the RS latch is connected to the PC host computer to receive a reset signal; the output end of the RS latch U7 is connected to the switch switching module 140; the power supply end of the RS latch U7 is connected to the first voltage. The RS latch U7 generates a corresponding state latch signal according to the voltage conversion signal or overvoltage conversion signal input to the switch switching module 140. When VBAT is overvoltage, the RS latch U7 generates a high-level state latch signal according to the high-level overvoltage detection signal and keeps the high-level state latch signal unchanged until the reset signal sent by the PC host computer is received and the latch is released to restore the normal operation of the circuit.

[0060] In some embodiments, the switch switching module 140 includes a sixth capacitor C6, a seventh capacitor C7 and an analog switch chip U8. Among them, the output end of the RS latch U7 is connected to the enable end of the analog switch chip U8; the first input end of the analog switch chip U8 is connected to the first voltage, and its first input end is also grounded through the seventh capacitor C7; the second input end of the analog switch chip U8 is grounded; the output end of the analog switch chip U8 is connected to the second input end of the solid-state relay U9; the power supply end of the analog switch chip U8 is connected to the first voltage, and its power supply end is also grounded through the sixth capacitor C6. Figure 2As shown, the analog switch chip U8 controls the on and off of the solid-state relay U9 through the internal single-pole double-throw switch according to the state latch signal of its enable terminal EN, thereby controlling the power output of the battery simulator. When the state latch signal is high, the first input terminal (A1 terminal) of the analog switch chip U8 and its output terminal (B terminal) are connected, and the analog switch chip U8 outputs a first voltage (5V voltage). At this time, the first input terminal and the second input terminal of the solid-state relay U9 have the same level and are both 5V, so the solid-state relay U9 is disconnected, cutting off the battery simulator from supplying power to VBAT, thereby achieving VBAT overvoltage protection. When the RS latch U7 receives the reset signal from the PC host computer, it releases the latch and outputs a low-level state latch signal. The second input terminal (A2 terminal) of the analog switch chip U8 and its output terminal (B terminal) are connected, and the analog switch chip U8 outputs a 0V voltage. At this time, the voltage difference between the first input terminal and the second input terminal of the solid-state relay U9 is 5V, so the solid-state relay U9 is turned on, and the battery simulator continues to provide power output for VBAT normally.

[0061] Specifically, the control logic for the VBAT voltage detection protection circuit in this embodiment is shown in Table 1 below.

[0062] Table 1

[0063] VBAT voltage U7_SET U7_RESET U7_Q U8 U9 <VL or >VH H L H H OFF >VL and <VH L H L L ON

[0064] In summary, Figure 2 The circuit for VBAT voltage detection and protection of the embodiment realizes effective monitoring and protection of the VBAT voltage through the cooperation between the power switch module 110, the abnormality detection module 120, the level conversion module 150, the state latch module 130 and the switch switching module 140. When the circuit is working normally, the battery simulator allows the VBAT to stably supply power to the VBAT, thereby ensuring the normal operation of the equipment; and in the case of VBAT overvoltage, it can quickly latch the overvoltage state and execute protection measures to avoid repeated power-on and cause more serious damage to the device under test. Therefore, the solution of this embodiment effectively reduces the risk of damage to the equipment during the test process and improves the stability and controllability of the overall test process.

[0065] It should be noted that Figure 2 The circuit for VBAT voltage detection protection shown in the embodiment is only a preferred circuit structure for achieving the purpose of the present invention. In other embodiments, each circuit module or device may also use other circuit structures that can achieve the same function, and the present application is not limited thereto.

[0066] In addition, the embodiment of the present application also provides a device for VBAT voltage detection protection, which includes a circuit for VBAT voltage detection protection as in the above embodiment, to achieve real-time monitoring and rapid response protection of the VBAT voltage during the main circuit board function test. For the circuit structure and working process of the device for VBAT voltage detection protection in this embodiment that are not described in detail, refer to the relevant parts of the circuit for VBAT voltage detection protection described above, and no further description is given here.

[0067] The above description is only a preferred embodiment of the present invention and does not limit the present invention in other forms. Any technician familiar with the profession may use the technical content disclosed above to change or modify it into an equivalent embodiment with equivalent changes and apply it to other fields. However, any simple modification, equivalent change and modification made to the above embodiment based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A circuit for VBAT voltage detection protection, characterized in that: It includes a power switch module, an abnormality detection module, a state latch module and a switch switching module; wherein, The power switch module is connected to the battery simulator, and is used to control the power output of the battery simulator to VBAT, and disconnect the power supply of the battery simulator to VBAT when VBAT is over-voltage, so as to perform over-voltage protection; The abnormality detection module is connected to the power switch module, and is used to detect the voltage signal of VBAT in real time, and compare the voltage signal with a set threshold voltage, generate a voltage detection signal and transmit it to the state latch module; The state latch module is connected to the abnormality detection module, and is used to generate a state latch signal according to the voltage detection signal and transmit it to the switch switching module, and keep the current state latch signal unchanged when VBAT overvoltage is detected until the signal latch is released after receiving a reset signal; The switch switching module is connected to the state latch module and the power switch module respectively, and is used to control the disconnection and conduction of the power switch module according to the state latch signal, so as to control whether the battery simulator supplies power to VBAT.

2. The circuit according to claim 1, characterized in that When the circuit is working normally, the power switch module is in the on state, and the battery simulator provides power output to VBAT; the abnormality detection module monitors the voltage signal of VBAT in real time, and if the VBAT voltage is within the preset threshold voltage range, a voltage detection signal is generated and transmitted to the state latch module; The state latch module is in an unlocked state, and generates a state latch signal to be transmitted to the switch switching module; after receiving the state latch signal, the switch switching module controls the circuit switch module to remain in the on state, and the battery simulator continues to supply power to VBAT; When VBAT is over-voltage, if the abnormality detection module detects that the VBAT voltage exceeds the preset threshold voltage range, it generates an over-voltage detection signal and transmits it to the status latch module; the status latch module generates a status latch signal based on the over-voltage detection signal and keeps the status latch signal unchanged; after receiving the status latch signal, the switch switching module controls the power switch module to disconnect, thereby cutting off the power supply of the battery simulator to VBAT.

3. The circuit according to claim 1 or 2, characterized in that: The power switch module includes a light emitting diode LED2, a fifteenth resistor R15, a sixteenth resistor R16 and a solid-state relay U9; The first input end of the solid-state relay U9 is connected to the first voltage through the sixteenth resistor R16, and the first voltage is also connected to the second input end of the solid-state relay U9 through the fifteenth resistor R15 and the light-emitting diode LED2 in sequence; the first output end of the solid-state relay U9 is connected to the abnormality detection module and connected to VBAT, and the second output end of the solid-state relay U9 is connected to the battery simulator; During normal operation, the solid-state relay U9 is in a closed state, and the battery simulator supplies power to VBAT; when VBAT is over-voltage, the solid-state relay U9 is controlled to be disconnected, cutting off the power supply of the battery simulator to VBAT.

4. The circuit according to claim 3, characterized in that The abnormality detection module includes a window comparator U10, an eighth capacitor C8, a seventeenth resistor R17, an eighteenth resistor R18 and a nineteenth resistor R19, and the seventeenth resistor R17, the eighteenth resistor R18 and the nineteenth resistor R19 form a voltage divider network; The window comparator U10 includes a first comparator CMP1, a second comparator CMP2 and a reference voltage source; one end of the seventeenth resistor R17 is connected to VBAT, and the other end is connected to one end of the eighteenth resistor R18 and connected to the positive input terminal INA of the first comparator CMP1; the other end of the eighteenth resistor R18 is connected to one end of the nineteenth resistor R19 and connected to the inverting input terminal INB of the second comparator CMP2, and the other end of the nineteenth resistor R19 is grounded; the inverting input terminal of the first comparator CMP1 is connected to the positive input terminal of the second comparator CMP2 and is grounded through the reference voltage source; the output terminal OUTA of the first comparator CMP1 is connected to the output terminal OUTB of the second comparator CMP2 and outputs a signal to the state latch module; the power supply terminal of the window comparator U10 is connected to the second voltage, and its power supply terminal is also grounded through the eighth capacitor C8.

5. The circuit according to claim 4, characterized in that The threshold voltage includes a high voltage threshold V H and low voltage threshold V L , the resistance values ​​of each resistor in the voltage divider network are set as follows: R total =R17+R18+R19=V H / I max , where R total is the total resistance, I max is the maximum current in the voltage divider network; R19=V REF / I max , where V REF A reference voltage provided by the reference voltage source; R18=(R total / V L )×V REF -R19; R17=R total -(R18+R19); In the formula, R17, R18 and R19 are the resistance values ​​of the seventeenth resistor, the eighteenth resistor and the nineteenth resistor respectively.

6. The circuit according to claim 4 or 5, characterized in that The first comparator CMP1 is used to detect whether the voltage of its positive input terminal INA is higher than the high voltage threshold V H , and when higher than the high voltage threshold V H When the voltage at the inverting input terminal INB is lower than the low voltage threshold V L , and when it falls below the low voltage threshold V L When the overvoltage detection signal is low, it outputs a low level.

7. The circuit according to claim 6, characterized in that A level conversion module is also provided between the abnormality detection module and the state latch module, and the level conversion module includes an NPN switch tube Q1, a thirteenth resistor R13 and a fourteenth resistor R14; The base of the switch tube Q1 is connected to the output end of the window comparator U10, and is connected to the second voltage through the fourteenth resistor R14; the second voltage is also connected to the collector of the switch tube Q1 through the thirteenth resistor R13, and the collector of the switch tube Q1 is also connected to the state latch module; the emitter of the switch tube Q1 is grounded; When the window comparator U10 outputs a high-level voltage detection signal, the switch tube Q1 is turned on and outputs a low-level voltage conversion signal to the state latch module; when the window comparator U10 outputs a low-level overvoltage detection signal, the switch tube Q1 is turned off and outputs a high-level overvoltage conversion signal to the state latch module.

8. The circuit according to claim 7, characterized in that The state latch module includes a twelfth resistor R12 and an RS latch U7; The collector of the switch tube Q1 is connected to the set end of the RS latch U7 through the twelfth resistor R12; the reset end of the RS latch is connected to the PC host computer to receive a reset signal; the output end of the RS latch U7 is connected to the switch switching module; the power supply end of the RS latch U7 is connected to the first voltage; The RS latch U7 generates a corresponding state latch signal according to the voltage conversion signal or overvoltage conversion signal input thereto and transmits it to the switch switching module. When VBAT is overvoltage, the RS latch U7 generates a high-level state latch signal according to the high-level overvoltage detection signal and keeps the high-level state latch signal unchanged until the reset signal sent by the PC host computer is received and the latch is released.

9. The circuit according to claim 8, characterized in that The switch switching module includes a sixth capacitor C6, a seventh capacitor C7 and an analog switch chip U8; The output end of the RS latch U7 is connected to the enable end of the analog switch chip U8; the first input end of the analog switch chip U8 is connected to the first voltage, and its first input end is also grounded through the seventh capacitor C7; the second input end of the analog switch chip U8 is grounded; the output end of the analog switch chip U8 is connected to the second input end of the solid-state relay U9; the power supply end of the analog switch chip U8 is connected to the first voltage, and its power supply end is also grounded through the sixth capacitor C6; The analog switch chip U8 controls the on and off of the solid-state relay U9 according to the state latch signal of its enable terminal to control the power output of the battery simulator, and when the state latch signal is at a high level, the solid-state relay U9 is disconnected, cutting off the battery simulator from supplying power to VBAT.

10. A device for VBAT voltage detection protection, characterized in that: The invention comprises a circuit for VBAT voltage detection and protection as claimed in any one of claims 1 to 9.

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