Circuit and method for detecting impedance abnormity of capacitor

Abstract

The invention provides a circuit and method for detecting capacitor impedance abnormity, and relates to the field of integrated circuits. The monitoring module is used for monitoring a target voltage value between the capacitor and the low-dropout linear regulator and sending a control signal or a signal value to the control module according to the size relation between the target voltage value and a preset threshold value; the control module controls the switch module to be in a closed or open state according to the control signal or the signal value. According to the method, potentially damaged capacitors are screened out, the stability of a PCB hardware circuit is improved, and delivery of products with potential quality problems is prevented. A designer makes a corresponding design improvement according to the found problem, the product stability and quality are improved, and the product return rate is reduced. In this way, the complete machine with the potential capacitor failure can be intercepted and correspondingly designed before delivery, the number of refunded and replaced goods after sale in the later period can be reduced, the use and experience feeling of a user is improved, and the brand image is kept and improved.

Description

Technical Field

[0001] The present invention relates to the technical field of integrated circuits, and in particular to a circuit and method for detecting abnormal capacitance impedance. Background Art

[0002] With the development trend of miniaturized products in the market, the size of printed circuit boards (PCBs) is getting smaller and smaller, and the customization is richer. As a result, the heat dissipation requirements are higher, resulting in an increase in the number of screw holes in the heat sink. The device layout is inevitably at the edge of the PCB board or near the screw holes, so the device is greatly affected by mechanical stress.

[0003] Before the whole machine leaves the factory, the components such as capacitors have been damaged by mechanical force, resulting in a decrease in capacitor impedance. However, the degree of damage is not enough to affect the occurrence of LDO (low dropout regulator) power failure. In most cases, the whole machine will not work properly until the user has used it for a period of time, or the machine cannot be restored after power failure. This causes the whole machine to not work properly, seriously affecting the customer's use and experience. Summary of the invention

[0004] In view of the above problems, the present invention proposes a circuit and method for detecting abnormal capacitance impedance.

[0005] An embodiment of the present invention provides a circuit for detecting abnormal capacitance impedance, the circuit comprising: a monitoring module, a control module and a switch module;

[0006] The monitoring module is used to monitor the target voltage value between the capacitor and the low voltage difference linear regulator, and send a control signal or a signal value to the control module according to the magnitude relationship between the target voltage value and a preset threshold value;

[0007] The control module controls the switch module to be in a closed or open state according to the control signal or the signal value;

[0008] Wherein, when the switch module is in the closed state, it indicates that the capacitor impedance is abnormal, and when the switch module is in the open state, it indicates that the capacitor impedance is normal.

[0009] Optionally, the monitoring module includes: a baseboard management controller or a voltage monitoring circuit;

[0010] The first end of the baseboard management controller or the voltage monitoring circuit is electrically connected to the first end of the capacitor, the second end of the resistor, and the second input end of the low voltage drop linear regulator respectively;

[0011] The second end of the baseboard management controller or the voltage monitoring circuit is electrically connected to the first end of the control module;

[0012] The first end of the resistor is electrically connected to the first end of the power supply;

[0013] The second end of the capacitor and the second end of the power supply are both grounded;

[0014] The first input terminal of the low voltage dropout linear regulator receives an input voltage.

[0015] Optionally, the control module includes: a programmable logic device or a field programmable logic gate array;

[0016] A first end of the programmable logic device or the field programmable logic gate array is electrically connected to a second end of the monitoring module;

[0017] The second end of the programmable logic device or the field programmable logic gate array is electrically connected to the control end of the switch module.

[0018] Optionally, the switch module includes: a field effect transistor;

[0019] The control end of the field effect transistor is electrically connected to the second end of the control module;

[0020] The first end of the field effect transistor is electrically connected to the output end of the low voltage difference linear regulator;

[0021] The second terminal of the field effect transistor is grounded.

[0022] Optionally, the field effect transistor is an NMOS transistor;

[0023] The gate of the NMOS tube is electrically connected to the second end of the control module as the control end;

[0024] The drain of the NMOS tube is electrically connected to the output end of the low voltage difference linear regulator as a first end;

[0025] The source of the NMOS tube is grounded as a second terminal.

[0026] Optionally, when the monitoring module is a baseboard management controller and the control module is a programmable logic device or a field programmable logic gate array, the baseboard management controller and the programmable logic device or the field programmable logic gate array are electrically connected via a custom bus, and the custom bus is only used to transmit the control signal or the signal value and read the status of two status registers inside the programmable logic device or the field programmable logic gate array;

[0027] When the states of the two status registers read by the baseboard management controller through the custom bus are inconsistent, the baseboard management controller records and stores the error information in its own error log in real time;

[0028] When the states of the two status registers read by the baseboard management controller through the custom bus are inconsistent, and the baseboard management controller is preset with preset error information, the baseboard management controller parses the time point and location information of the error occurrence and reports it to the host computer;

[0029] When the programmable logic device or the field programmable logic gate array can be used to record the timing state of the mainboard, the baseboard management controller monitors and records the timing state of the mainboard in real time through the custom bus;

[0030] When the baseboard management controller detects that the target voltage value is abnormal, it reports it to the host computer through a preset protocol.

[0031] Optionally, the preset threshold is built into the register of the baseboard management controller itself;

[0032] After the baseboard management controller monitors and obtains the target voltage value, it compares the target voltage value with the preset threshold value, and generates and outputs the control signal according to the comparison result;

[0033] Wherein, the control signal includes: a first signal or a second signal;

[0034] The first signal is transmitted to the programmable logic device or the field programmable logic gate array through the custom bus, so that the programmable logic device or the field programmable logic gate array outputs the first signal to the switch module, thereby controlling the switch module to be in a closed or open state;

[0035] The second signal is transmitted to the programmable logic device or the field programmable gate array through the custom bus, so that the programmable logic device or the field programmable gate array changes the value of its internal register, thereby changing the signal level value output by the programmable logic device or the field programmable gate array to the switch module, thereby controlling the switch module to be in a closed or open state.

[0036] Optionally, the preset threshold is built into the register of the baseboard management controller itself;

[0037] After the baseboard management controller monitors and obtains the target voltage value, it compares the target voltage value with the preset threshold value, and generates and outputs the signal value according to the comparison result;

[0038] The signal value is transmitted to the programmable logic device or the field programmable gate array through the custom bus, so that the programmable logic device or the field programmable gate array changes the value of its internal register, thereby changing the signal level value output by the programmable logic device or the field programmable gate array to the switch module, thereby controlling the switch module to be in a closed or open state.

[0039] Optionally, the preset threshold is greater than a turn-on voltage value of the low-dropout linear regulator, and less than an input voltage value received by a first input terminal of the low-dropout linear regulator;

[0040] Wherein, if the target voltage value is less than the start-up voltage value, the low voltage dropout linear regulator does not work, the low voltage dropout linear regulator has no output voltage, and the layout and wiring of the optimized circuit are modified again;

[0041] If the target voltage value is greater than the preset threshold value, the low voltage dropout linear regulator works normally, the switch module is in the disconnected state, the low voltage dropout linear regulator outputs voltage normally, and the switch module is removed after mass production;

[0042] If the target voltage value is greater than the turn-on voltage value and less than the preset threshold, the low voltage dropout linear regulator works normally, the switch module is in the closed state, the output voltage of the low voltage dropout linear regulator is directly grounded, and the layout and wiring of the optimized circuit are modified again.

[0043] An embodiment of the present invention provides a method for detecting abnormal capacitance impedance, the method being applied to any of the above-mentioned circuits for detecting abnormal capacitance impedance, the method comprising:

[0044] Utilizing the target voltage value of the monitoring module, and comparing the magnitude relationship between the target voltage value and a preset threshold value;

[0045] If the target voltage value is greater than the preset threshold value, the monitoring module is used to send the control signal or the signal value to the control module, so that the switch module is in the disconnected state and the low voltage drop linear regulator outputs the voltage normally;

[0046] If the target voltage value is greater than the turn-on voltage value of the low voltage dropout linear regulator and less than the preset threshold value, the monitoring module is used to send the control signal or the signal value to the control module, so that the switch module is in the closed state, and the output voltage of the low voltage dropout linear regulator is directly grounded;

[0047] If the target voltage value is less than the start-up voltage value, the monitoring module does not send the control signal or the signal value to the control module, the low-dropout linear regulator does not work, and the low-dropout linear regulator has no output voltage.

[0048] The present invention provides a circuit for detecting abnormal capacitor impedance, wherein a monitoring module is used to monitor a target voltage value between a capacitor and a low voltage difference linear regulator, and sends a control signal or a signal value to a control module according to a magnitude relationship between the target voltage value and a preset threshold value; the control module controls a switch module to be in a closed or open state according to the control signal or the signal value; when the switch module is in a closed state, it indicates that the capacitor impedance is abnormal, and when the switch module is in an open state, it indicates that the capacitor impedance is normal.

[0049] The circuit for detecting abnormal capacitor impedance proposed in the present invention creatively proposes a circuit for detecting abnormal capacitor impedance, which is not currently available, in view of the problem that the traditional potential capacitor impedance abnormality leads to the failure of the whole machine. When the whole machine leaves the factory and has not yet been sold to the user, the state of the switch module is determined by monitoring the size relationship between the target voltage value and the preset threshold between the capacitor and the low voltage difference linear regulator, and then determining whether the capacitor impedance is abnormal according to the state of the switch module. Thereby, the capacitor with potential damage is screened out, the stability of the hardware circuit of the PCB board is improved, and the shipment of products with potential quality problems is prevented. The designers make corresponding design improvements for the problems found, improve product stability and quality, and reduce the product return rate. In this way, such potential capacitor failure whole machines can be intercepted and designed accordingly before shipment, which can reduce the number of returns and exchanges after later sales, improve user use and experience, maintain and enhance the brand image, and have high practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Moreover, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0051] Figure 1 It is a modular schematic diagram of a circuit for detecting abnormal capacitance impedance according to an embodiment of the present invention;

[0052] Figure 2 is a circuit structure diagram of an exemplary detection capacitor impedance in an embodiment of the present invention;

[0053] Figure 3 The present invention is a flowchart of a method for detecting abnormal capacitance impedance according to an embodiment of the present invention. DETAILED DESCRIPTION

[0054] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, are only part of the embodiments of the present invention, not all of the embodiments, and are not used to limit the present invention.

[0055] The inventors have found that currently, before the whole machine leaves the factory, components such as capacitors may have been damaged by mechanical force when sold to users, resulting in a decrease in capacitor impedance, but the degree of damage is not enough to affect the occurrence of LDO (low dropout regulator) power outages. In most cases, the whole machine will not show abnormal operation or cannot be restored after power outages until the user has used it for a period of time, resulting in the whole machine not being able to work normally, seriously affecting the customer's use and experience.

[0056] The inventors further studied and found that the reason for the above problems is that most of the PCBs currently use MLCC (Multi-layer Ceramic Capacitor), whose main component is ceramic. During the processes of placing components, separating boards, screwing, fastening connectors, and drop testing in the factory, it is very likely that the capacitors will be squeezed and cracked due to excessive mechanical stress, resulting in potential leakage failure, reduced IR value (that is, abnormal capacitor impedance), and increased leakage current.

[0057] However, the insulation impedance value at this time may be higher than the on-board failure value (that is, the degree of damage has not affected the power-off of the low-dropout linear regulator, so it will not immediately show abnormal function on the board. However, when the damaged capacitor is powered on for a period of time, the local heating caused by leakage will continue to reduce the insulation performance of the ceramic dielectric, aggravate its leakage, and further reduce the impedance value until it affects the circuit function, and finally show power-off or abnormal alarm operation of the whole machine, and cannot work normally, affecting customer use.

[0058] The inventors conducted further research and creatively discovered that there are two reasons why this problem has not been solved:

[0059] The first type is: the user himself does not care about the problem. When the problem occurs after using it for a period of time, the user thinks it is caused by his own reasons, such as: the power supply voltage provided to the device is unstable, the working environment of the device is poor, etc.

[0060] The second reason is: currently, the test of the whole machine before leaving the factory is only to see whether the output voltage value of the low-voltage difference linear regulator meets the regulations. For example, if the output voltage value of the low-voltage difference linear regulator is required to be greater than 3.3V, then the whole machine before leaving the factory will simply detect whether the output voltage value of the low-voltage difference linear regulator is greater than 3.3V. If it is greater than 3.3V, the whole machine is considered normal. At this time, if there is potential mechanical damage to the capacitor, it does not affect the output voltage value of the low-voltage difference linear regulator. However, after the user has used it for a period of time, the abnormal impedance of the capacitor will cause the low-voltage difference linear regulator to lose power, affecting the normal operation of the whole machine.

[0061] From the above description, it can be seen that the factory test before the whole machine is shipped cannot detect the capacitor with abnormal impedance. In view of this creative discovery, the inventor has creatively proposed a circuit and method for detecting abnormal capacitor impedance of the present invention after a lot of research and actual measurement. The technical solution proposed by the present invention is explained and illustrated in detail below.

[0062] The circuit for detecting abnormal capacitance impedance of the present invention refers to Figure 1 The modular schematic diagram of the circuit for detecting abnormal capacitor impedance shown in the figure includes: a monitoring module, a control module and a switch module. The monitoring module is used to monitor the target voltage value between the capacitor and the low voltage drop linear regulator, and send a control signal or signal value to the control module according to the magnitude relationship between the target voltage value and the preset threshold value.

[0063] The control module controls the switch module to be in a closed or open state according to the control signal or signal value; when the switch module is in a closed state, it indicates that the capacitor impedance is abnormal, and when the switch module is in an open state, it indicates that the capacitor impedance is normal.

[0064] Through the above circuit structure, potentially damaged capacitors can be screened out before the whole machine leaves the factory and is not sold to users, thereby improving the stability of the PCB board hardware circuit and preventing the shipment of products with potential quality problems. Designers make corresponding design improvements based on the problems found to improve product stability and quality and reduce product return rates. In this way, such machines with potential capacitor failures can be intercepted and designed accordingly before shipment, which can reduce the number of returns and exchanges after later sales, improve user usage and experience, and maintain and enhance the brand image.

[0065] In an embodiment of the present invention, the monitoring module can be implemented in multiple ways. Preferably, the monitoring module includes: a baseboard management controller or a voltage monitoring circuit; the first end of the baseboard management controller or the voltage monitoring circuit is electrically connected to the first end of the capacitor, the second end of the resistor, and the second input end of the low-dropout linear regulator, respectively; the second end of the baseboard management controller (BMC) or the voltage monitoring circuit is electrically connected to the first end of the control module.

[0066] The first end of the resistor is electrically connected to the first end of the power supply; the second end of the capacitor and the second end of the power supply are both grounded; and the first input end of the low voltage difference linear regulator receives an input voltage.

[0067] If the capacitor impedance is normal, the voltage value generated by the power supply is almost equal to the target voltage value. If the capacitor impedance is abnormal, the capacitor impedance will produce a voltage divider with the resistor, and the target voltage value will be lower and lower than the voltage value generated by the power supply.

[0068] In the embodiment of the present invention, the control module is used to control the switch module. Based on the current PCB board circuit structure, the preferred structure of the control module includes: a complex programmable logic device (CPLD) or a field programmable gate array (FPGA). The first end of the programmable logic device or the field programmable gate array is electrically connected to the second end of the monitoring module; if the monitoring module is a baseboard management controller, the first end of the programmable logic device or the field programmable gate array is electrically connected to the second end of the baseboard management controller. The second end of the programmable logic device or the field programmable gate array is electrically connected to the control end of the switch module.

[0069] In the embodiment of the present invention, the switch module is controlled by the control module, and can be in a closed state or an open state. A preferred switch module includes: a field effect transistor; a control end of the field effect transistor is electrically connected to a second end of the control module; a first end of the field effect transistor is electrically connected to an output end of a low voltage difference linear regulator; and a second end of the field effect transistor is grounded.

[0070] There are many types of field effect transistors, and the better field effect transistor is NMOS (NMetal-Oxide-Semiconductor Field-Effect Transistor, NMOSFET, N-type metal-oxide-semiconductor field-effect transistor, generally abbreviated as NMOS tube). The gate of the NMOS tube is electrically connected to the second end of the control module as the control end; the drain of the NMOS tube is electrically connected to the output end of the low voltage difference linear regulator as the first end; the source of the NMOS tube is grounded as the second end.

[0071] As can be seen from the above description, if the capacitor impedance is normal, the voltage value generated by the power supply is almost equal to the target voltage value, and if the capacitor impedance is abnormal, the capacitor impedance will generate a voltage divider with the resistor, and the target voltage value will be reduced and lower than the voltage value generated by the power supply. Therefore, in order to detect whether the capacitor impedance is abnormal, the preset threshold is set to be greater than the turn-on voltage value of the low-dropout linear regulator and less than the input voltage value received by the first input terminal of the low-dropout linear regulator.

[0072] Among them, if the target voltage value is less than the turn-on voltage value, the low-voltage difference linear regulator does not work, and the low-voltage difference linear regulator has no output voltage. In this case, the target voltage value does not reach the turn-on voltage value required by the low-voltage difference linear regulator, and it can be considered that the capacitor impedance is seriously abnormal or the capacitor is damaged. The monitoring module does not need to send any signal or signal value to the control module because the low-voltage difference linear regulator does not work. In this case, it can be directly determined that the problem is the capacitor.

[0073] If the target voltage value is greater than the preset threshold, the low-voltage dropout linear regulator works normally, the switch module is in the disconnected state, and the low-voltage dropout linear regulator outputs voltage normally. In this case, it can be considered that the capacitor impedance is normal and there is no potential problem of mechanical force loss. Therefore, the switch module is in the disconnected state and the low-voltage dropout linear regulator outputs voltage normally.

[0074] If the target voltage value is greater than the turn-on voltage value and less than the preset threshold value, the low-voltage difference linear regulator works normally, the switch module is in a closed state, and the output voltage of the low-voltage difference linear regulator is directly grounded. In this case, since the target voltage value is greater than the turn-on voltage, the low-voltage difference linear regulator works normally, but due to the abnormal capacitance impedance, the target voltage value is less than the preset threshold value, so the output voltage of the low-voltage difference linear regulator is directly grounded to distinguish it from the case where the target voltage value is less than the turn-on voltage value. In this case, the capacitor has been damaged by mechanical force and there is a potential abnormal capacitance impedance problem, but if only according to the traditional factory test method, the output voltage of the low-voltage difference linear regulator is normal, it will be considered that the whole machine is qualified, and it is impossible to detect that the capacitor has been damaged by mechanical force and there is a potential abnormal capacitance impedance problem. In this case, the circuit of the present invention closes the switch module so that the low-voltage difference linear regulator works normally but the output voltage is grounded, and the abnormal capacitance impedance can be directly detected, which is convenient and fast, and the circuit structure is simple (there may be a substrate management controller or a programmable logic device or a field programmable logic gate array on the PCB board, which can be directly reused), and does not require much area overhead.

[0075] In order to better understand the circuit for detecting capacitance impedance of the present invention, refer to Figure 2 An exemplary circuit structure diagram for detecting capacitor impedance is shown. Figure 2 In the figure, the baseboard management controller BMC represents the monitoring module, the programmable logic device CPLD represents the control module, and the NMOS tube Q1 represents the switch module, but it does not mean that these modules can only be these components. All components, combination circuits or integrated circuits that can realize the corresponding functions of each module can be replaced.

[0076] Figure 2 DC1 represents a power supply that provides an input voltage Vin, and DC2 represents a power supply that provides a target voltage Vbias. The negative electrode of the power supply DC1 is electrically connected to the first end of the capacitor C2, and the second end of the capacitor C2 is grounded. The positive electrode of the power supply DC1 is electrically connected to an input end of the low-dropout linear regulator LDO, that is, the low-dropout linear regulator LDO receives the input voltage Vin.

[0077] The capacitor C1 is a capacitor that may be potentially damaged by mechanical force. The first end of the capacitor C1 is electrically connected to the second end of the resistor R1, the first end of the baseboard management controller BMC, and the other input end of the low dropout linear regulator LDO.

[0078] The first end of the resistor R1 is connected to the positive electrode of the power supply DC2, and the negative electrode of the power supply DC2 and the second end of the capacitor C1 are both grounded. The second end of the baseboard management controller BMC is electrically connected to the first end of the programmable logic device CPLD, and the second end of the programmable logic device CPLD is electrically connected to the gate of the NMOS tube Q1.

[0079] The drain of the NMOS tube Q1 is electrically connected to the output voltage terminal of the low-voltage difference linear regulator LDO, and the source of the NMOS tube Q1 is grounded. The detection voltage terminal of the low-voltage difference linear regulator LDO is electrically connected to the second end of the resistor R2 and the first end of the resistor R3, respectively. The first end of the resistor R2 is electrically connected to the output voltage terminal Vout of the low-voltage difference linear regulator LDO and the first end of the capacitor C3, respectively. The second end of the resistor R3 is grounded. The second end of the capacitor C3 is also grounded. Resistors R2 and R3 divide the output voltage Vout of the low-voltage difference linear regulator LDO to generate a detection voltage Vsense, which is used by the low-voltage difference linear regulator LDO itself to detect whether its output voltage Vout meets the requirements. The function of the capacitor C3 is to filter and stabilize the output voltage Vout to provide it to the subsequent circuit for use.

[0080] The target voltage Vbias in the low-dropout linear regulator LDO is generally lower than the turn-on voltage to absolutely affect the output voltage Vout of the low-dropout linear regulator LDO. However, the damaged capacitor C1 with abnormal impedance does not necessarily cause the target voltage Vbias to be lower than the turn-on voltage at the beginning. Most of the time, the whole machine has been working on the station for a period of time, and the high temperature environment aggravates the damage of capacitor C1 to the target voltage Vbias voltage lower than the turn-on voltage, which will cause an irreversible power failure problem and seriously affect the user experience. The traditional factory test only detects whether the output voltage Vout of the low-dropout linear regulator LDO meets the regulations, and cannot check whether the capacitor C1 is normal or not. Therefore, it is particularly important to add target voltage Vbias monitoring in the factory test link.

[0081] When capacitor C1 is damaged by mechanical force and exhibits abnormal impedance, it will generate voltage division with capacitor R1. The baseboard management controller BMC monitors this target voltage value. When it detects that the target voltage value is lower than the preset threshold voltage, it will trigger the programmable logic device CPLD to send a low-to-high signal, so that the NMOS tube Q1 is in a closed state, and the output voltage Vout of the low-dropout linear regulator LDO is pulled down to ground. In this way, the pre-factory test can detect the abnormal output voltage Vout of the low-dropout linear regulator LDO, and the potentially damaged whole machine can be screened out before shipment to avoid problems in subsequent use by users and improve product quality and reliability.

[0082] Under normal circumstances, the target voltage Vbias of capacitor C1 is approximately equal to the voltage of power supply DC2. At this time, the target voltage Vbias monitored by the baseboard management controller BMC must be higher than the preset threshold. The programmable logic device CPLD will output a low signal, so that the NMOS tube Q1 is always in the disconnected state, and the output voltage Vout of the low-dropout linear regulator LDO is normal.

[0083] If the NMOS tube Q1 is in the disconnected state, it indicates that the probability of the capacitor C1 being damaged is low. The NMOS tube Q1 can be removed after mass production, that is, the NMOS tube Q1 is not processed, which can save the cost of the whole machine. Of course, the NMMOS tube can also be kept in the whole machine. The cost will increase slightly, but it will be convenient for users. Users can test the structure of the above circuit by themselves to determine whether the problem is caused by the damage of the capacitor C1.

[0084] If the NMOS tube Q1 is in the closed state, it indicates that the probability of capacitor C1 being damaged is high. Designers need to learn from the lesson, re-modify and optimize the layout (layout and routing), and then verify the board again until the risk of abnormal impedance of capacitor C1 being damaged before leaving the factory is eliminated.

[0085] In an embodiment of the present invention, when the monitoring module is a baseboard management controller and the control module is a programmable logic device or a field programmable gate array, the baseboard management controller and the programmable logic device or the field programmable gate array are electrically connected through a customized bus. The customized bus is different from other buses and is only used to transmit control signals or signal values, and to read the status of two status registers inside the programmable logic device or the field programmable gate array.

[0086] When the states of two status registers read by the baseboard management controller through the customized bus are inconsistent, the baseboard management controller can record and store the error information in real time in its own error log; when the states of two status registers read by the baseboard management controller through the customized bus are inconsistent, and preset error information is preset in the baseboard management controller, the baseboard management controller parses the time and location information of the error and reports it to the host computer, which can provide key information that relevant staff can directly locate.

[0087] When a programmable logic device or a field programmable logic gate array can be used to record the timing status of the motherboard, for example: the characteristics of the customizable pins and internal registers of the programmable logic device or the field programmable logic gate array can be utilized to add registers inside the programmable logic device or the field programmable logic gate array of the existing PCB motherboard to record the timing status of the motherboard. The baseboard management controller monitors and records the timing status of the motherboard in real time through a customized bus, thereby realizing the monitoring and recording of the timing status of the motherboard without adding motherboard hardware.

[0088] In addition, if the baseboard management controller detects that the target voltage value is abnormal, it can report it to the host computer in time through a preset protocol, such as SMTP, so that relevant staff can quickly locate the fault location and perform maintenance in time.

[0089] As for how the baseboard management controller determines whether the target voltage value is abnormal, the optimal method is: a preset threshold is built into the baseboard management controller's own register; after the baseboard management controller monitors the target voltage value, it compares the target voltage value with the preset threshold, and generates and outputs a control signal based on the comparison result.

[0090] Among them, the control signal includes: a first signal or a second signal. The first signal is transmitted to the programmable logic device or the field programmable logic gate array through a custom bus, so that the programmable logic device or the field programmable logic gate array outputs the first signal to the switch module, thereby controlling the switch module to be in a closed or open state; that is, the first signal is equivalent to being forwarded by the programmable logic device or the field programmable logic gate array to the switch module, and is directly used to control the switch module to be in different states.

[0091] The second signal is transmitted to the programmable logic device or field programmable logic gate array through the custom bus, so that the programmable logic device or field programmable logic gate array changes the value of its internal register, thereby changing the signal level value output by the programmable logic device or field programmable logic gate array to the switch module, thereby controlling the switch module to be in a closed or open state. That is, the second signal is not directly forwarded by the programmable logic device or field programmable logic gate array, but changes the value of the programmable logic device or field programmable logic gate array's internal register, thereby changing the level value of the signal sent by the programmable logic device or field programmable logic gate array to the switch module, thereby controlling the switch module to be in a closed or open state.

[0092] Another method is: after the baseboard management controller monitors and obtains the target voltage value, it compares the target voltage value with the preset threshold value, and generates and outputs a signal value according to the comparison result. The signal value is transmitted to the programmable logic device or field programmable logic gate array through a custom bus, so that the programmable logic device or field programmable logic gate array changes the value of its internal register, thereby changing the signal level value output by the programmable logic device or field programmable logic gate array to the switch module, thereby controlling the switch module to be in a closed or open state.

[0093] Regardless of which of the above methods is used, it is necessary to determine whether the target voltage value is abnormal based on the magnitude relationship between the target voltage value and the preset threshold value, thereby determining whether the capacitor impedance is abnormal.

[0094] Based on the above circuit for detecting abnormal capacitance impedance, the embodiment of the present invention also provides a method for detecting abnormal capacitance impedance, referring to Figure 3 The flowchart of the method for detecting abnormal capacitance impedance shown in FIG. 1 includes:

[0095] Step 301: Utilize the target voltage value of the monitoring module and compare the magnitude relationship between the target voltage value and a preset threshold value.

[0096] Step 302: If the target voltage value is greater than the preset threshold, the monitoring module is used to send a control signal or a signal value to the control module, so that the switch module is in a disconnected state and the low voltage difference linear regulator outputs the voltage normally.

[0097] Step 303: If the target voltage value is greater than the start-up voltage value of the low-dropout linear regulator and less than the preset threshold, the monitoring module sends a control signal or signal value to the control module to make the switch module in a closed state, and the output voltage of the low-dropout linear regulator is directly grounded.

[0098] Step 304: If the target voltage value is less than the start-up voltage value, the monitoring module does not send a control signal or the signal value to the control module, the low-dropout linear regulator does not work, and the low-dropout linear regulator has no output voltage.

[0099] The method of steps 301 to 304 above, combined with Figure 2 The circuit structure diagram shown can be summarized as:

[0100] If the impedance of capacitor C1 is normal and the baseboard management controller BMC (representing the monitoring module) monitors that the target voltage value Vbias is higher than the preset threshold, the programmable logic controller CPLD (representing the control module) controls the output to the NMOS tube Q1 (representing the switch module) to maintain a low level, the NMOS tube Q1 remains disconnected, the low-dropout linear regulator LDO works normally, the output voltage Vout, and the whole machine passes the factory test PASS.

[0101] If the impedance of capacitor C1 is abnormally serious due to external mechanical force or capacitor C1 is damaged, when the baseboard management controller BMC monitors the target voltage value Vbias lower than the start-up voltage, the low-dropout linear regulator LDO will not start working, that is, the low-dropout linear regulator LDO has no output voltage, and the whole machine fails in the factory test. When the fail rate is high, the designer needs to modify and optimize the layout, and test and verify the board again until the whole machine meets the baseline standard before mass production and sale.

[0102] If the capacitor C1 is subjected to external mechanical force and the impedance is abnormal, when the baseboard management controller BMC monitors the target voltage value Vbias higher than the start-up voltage and lower than the preset threshold, the low-voltage difference linear regulator LDO will start working, that is, the low-voltage difference linear regulator LDO outputs the voltage Vout; but the baseboard management controller BMC will send a control signal or signal value, so that the programmable logic controller CPLD controls the output to the NMOS tube Q1. The low-level signal becomes a high-level signal, and the NMOS tube Q1 becomes closed, and the output voltage Vout of the low-voltage difference linear regulator LDO is directly grounded. At this time, the factory test of the whole machine also fails. When the fail rate is high, the designer needs to modify and optimize the layout, and test and verify again until the PASS rate of the factory test of the whole machine meets the baseline standard before it can be mass-produced and sold. Preferably, after mass production, you can choose to remove the NMOS tube Q1 to reduce the cost of the whole machine.

[0103] To summarize, in the circuit for detecting abnormal capacitor impedance proposed in the present invention, the monitoring module is used to monitor the target voltage value between the capacitor and the low voltage difference linear regulator, and sends a control signal or signal value to the control module according to the relationship between the target voltage value and the preset threshold value; the control module controls the switch module to be in a closed or open state according to the control signal or signal value; when the switch module is in a closed state, it indicates that the capacitor impedance is abnormal, and when the switch module is in an open state, it indicates that the capacitor impedance is normal.

[0104] The circuit for detecting abnormal capacitor impedance proposed in the present invention creatively proposes a circuit for detecting abnormal capacitor impedance, which is not currently available, in view of the problem that the traditional potential capacitor impedance abnormality leads to the failure of the whole machine. When the whole machine leaves the factory and has not yet been sold to the user, the state of the switch module is determined by monitoring the size relationship between the target voltage value and the preset threshold between the capacitor and the low voltage difference linear regulator, and then determining whether the capacitor impedance is abnormal according to the state of the switch module. Thereby, the capacitor with potential damage is screened out, the stability of the hardware circuit of the PCB board is improved, and the shipment of products with potential quality problems is prevented. The designers make corresponding design improvements for the problems found, improve product stability and quality, and reduce the product return rate. In this way, such potential capacitor failure whole machines can be intercepted and designed accordingly before shipment, which can reduce the number of returns and exchanges after later sales, improve user use and experience, maintain and enhance the brand image, and have high practicality.

[0105] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the embodiments of the present invention.

[0106] Finally, it should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or terminal device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or terminal device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or terminal device including the elements.

[0107] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation modes, which are merely illustrative rather than restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are within the protection of the present invention.

Claims

1. A circuit for detecting abnormal capacitance impedance, characterized in that: The circuit comprises: a monitoring module, a control module and a switch module; The monitoring module is used to monitor the target voltage value between the capacitor and the low voltage difference linear regulator, and send a control signal or a signal value to the control module according to the magnitude relationship between the target voltage value and a preset threshold value; The control module controls the switch module to be in a closed or open state according to the control signal or the signal value; Wherein, when the switch module is in the closed state, it indicates that the capacitor impedance is abnormal, and when the switch module is in the open state, it indicates that the capacitor impedance is normal.

2. The circuit according to claim 1, characterized in that The monitoring module includes: a baseboard management controller or a voltage monitoring circuit; The first end of the baseboard management controller or the voltage monitoring circuit is electrically connected to the first end of the capacitor, the second end of the resistor, and the second input end of the low voltage drop linear regulator respectively; The second end of the baseboard management controller or the voltage monitoring circuit is electrically connected to the first end of the control module; The first end of the resistor is electrically connected to the first end of the power supply; The second end of the capacitor and the second end of the power supply are both grounded; The first input terminal of the low voltage dropout linear regulator receives an input voltage.

3. The circuit according to claim 1, characterized in that The control module includes: a programmable logic device or a field programmable logic gate array; The first end of the programmable logic device or the field programmable logic gate array is electrically connected to the second end of the monitoring module; The second end of the programmable logic device or the field programmable logic gate array is electrically connected to the control end of the switch module.

4. The circuit according to claim 1, characterized in that The switch module includes: a field effect transistor; The control end of the field effect transistor is electrically connected to the second end of the control module; The first end of the field effect transistor is electrically connected to the output end of the low voltage difference linear regulator; The second terminal of the field effect transistor is grounded.

5. The circuit according to claim 4, characterized in that The field effect transistor is an NMOS tube; The gate of the NMOS tube is electrically connected to the second end of the control module as the control end; The drain of the NMOS tube is electrically connected to the output end of the low voltage difference linear regulator as a first end; The source of the NMOS tube is grounded as a second terminal.

6. The circuit according to claim 1, characterized in that When the monitoring module is a baseboard management controller and the control module is a programmable logic device or a field programmable logic gate array, the baseboard management controller is electrically connected to the programmable logic device or the field programmable logic gate array through a custom bus, and the custom bus is only used to transmit the control signal or the signal value and read the status of two status registers inside the programmable logic device or the field programmable logic gate array; When the states of the two status registers read by the baseboard management controller through the custom bus are inconsistent, the baseboard management controller records and stores the error information in its own error log in real time; When the states of the two status registers read by the baseboard management controller through the custom bus are inconsistent, and the baseboard management controller is preset with preset error information, the baseboard management controller parses the time point and location information of the error occurrence and reports it to the host computer; When the programmable logic device or the field programmable logic gate array can be used to record the timing state of the mainboard, the baseboard management controller monitors and records the timing state of the mainboard in real time through the custom bus; When the baseboard management controller detects that the target voltage value is abnormal, it reports it to the host computer through a preset protocol.

7. The circuit according to claim 6, characterized in that The preset threshold is built into the register of the baseboard management controller itself; After the baseboard management controller monitors and obtains the target voltage value, it compares the target voltage value with the preset threshold value, and generates and outputs the control signal according to the comparison result; Wherein, the control signal includes: a first signal or a second signal; The first signal is transmitted to the programmable logic device or the field programmable logic gate array through the custom bus, so that the programmable logic device or the field programmable logic gate array outputs the first signal to the switch module, thereby controlling the switch module to be in a closed or open state; The second signal is transmitted to the programmable logic device or the field programmable gate array through the custom bus, so that the programmable logic device or the field programmable gate array changes the value of its internal register, thereby changing the signal level value output by the programmable logic device or the field programmable gate array to the switch module, thereby controlling the switch module to be in a closed or open state.

8. The circuit according to claim 6, characterized in that The preset threshold is built into the register of the baseboard management controller itself; After the baseboard management controller monitors and obtains the target voltage value, it compares the target voltage value with the preset threshold value, and generates and outputs the signal value according to the comparison result; The signal value is transmitted to the programmable logic device or the field programmable gate array through the custom bus, so that the programmable logic device or the field programmable gate array changes the value of its internal register, thereby changing the signal level value output by the programmable logic device or the field programmable gate array to the switch module, thereby controlling the switch module to be in a closed or open state.

9. The circuit according to claim 1, characterized in that The preset threshold is greater than the turn-on voltage value of the low voltage difference linear regulator and less than the input voltage value received by the first input terminal of the low voltage difference linear regulator; Wherein, if the target voltage value is less than the start-up voltage value, the low voltage dropout linear regulator does not work, the low voltage dropout linear regulator has no output voltage, and the layout and wiring of the optimized circuit are modified again; If the target voltage value is greater than the preset threshold value, the low voltage dropout linear regulator works normally, the switch module is in the disconnected state, the low voltage dropout linear regulator outputs voltage normally, and the switch module is removed after mass production; If the target voltage value is greater than the turn-on voltage value and less than the preset threshold, the low voltage dropout linear regulator works normally, the switch module is in the closed state, the output voltage of the low voltage dropout linear regulator is directly grounded, and the layout and wiring of the optimized circuit are modified again.

10. A method for detecting abnormal capacitance impedance, characterized in that: The method is applied to the circuit for detecting abnormal capacitance impedance according to any one of claims 1 to 9, and the method comprises: Utilizing the target voltage value of the monitoring module, and comparing the magnitude relationship between the target voltage value and a preset threshold value; If the target voltage value is greater than the preset threshold value, the monitoring module is used to send the control signal or the signal value to the control module, so that the switch module is in the disconnected state and the low voltage drop linear regulator outputs the voltage normally; If the target voltage value is greater than the turn-on voltage value of the low voltage dropout linear regulator and less than the preset threshold value, the monitoring module is used to send the control signal or the signal value to the control module, so that the switch module is in the closed state, and the output voltage of the low voltage dropout linear regulator is directly grounded; If the target voltage value is less than the start-up voltage value, the monitoring module does not send the control signal or the signal value to the control module, the low-dropout linear regulator does not work, and the low-dropout linear regulator has no output voltage.

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