Hardware power supply over-voltage and under-voltage monitoring and fault self-locking circuit at each level

Abstract

The invention provides a hardware power supply over-voltage and under-voltage monitoring and fault self-locking circuit. The hardware power supply over-voltage and under-voltage monitoring and fault self-locking circuit comprises a reference power supply which is used for forming a voltage reference source; the over-voltage and under-voltage monitoring circuit is used for setting a monitoring threshold value for each stage of power supply voltage and carrying out over-voltage and under-voltage monitoring on the set monitoring threshold value; the isolation circuit plays roles of isolation and switching; the time delay circuit can control the over-voltage and under-voltage monitoring circuit to be invalid at the moment of electrifying and starting the equipment and when the whole board is under-voltage, and the over-voltage and under-voltage monitoring circuit is opened after the module is normally started; the self-locking circuit is used for controlling the power cutting circuit to act; and the power cutting circuit is used for directly cutting off the input end of the primary power supply when an overvoltage or undervoltage fault occurs, preventing a post-stage circuit device from being damaged and outputting an out-of-control signal. When the overvoltage or undervoltage fault occurs, the power cutting circuit can act immediately, effectively prevents the missing of the optimal protection time, can perform self power supply monitoring, does not need an additional power supply to monitor the primary power supply, and is high in reliability. And the cost is effectively saved.

Description

Technical Field

[0001] The invention belongs to the technical field of electronic circuit design, in particular to a hardware power supply over-voltage and under-voltage monitoring and fault self-locking circuit for each level. Background Art

[0002] In the field of industrial automation control systems, in order to improve the safety of equipment, it is generally necessary to monitor and control the input voltage to prevent excessive voltage input from damaging the subsequent circuit IC devices. Generally, the maximum withstand voltage of IC devices is about 36 to 40V. When the input voltage is too large in an instant, it is very easy to damage the subsequent devices, causing product failure and causing uncontrollable safety problems.

[0003] In order to solve the above technical problems, the existing technology usually adopts the following two technical solutions for monitoring and control:

[0004] ① Add a hot-swap circuit to limit overcurrent and overvoltage. When the feedback fails, the voltage is restarted back and forth through the protection circuit, or a voltage clamping diode is added to the IC power supply end to limit the voltage. When the feedback fails, the voltage is clamped at a fixed value through the overvoltage clamping circuit, or an integrated voltage monitoring chip is used to monitor the voltage. When the voltage is abnormal, a signal is output to the CPU, and then the CPU controls the relevant circuits to perform protection operations to prevent circuit failure and safety failure.

[0005] ② In order to solve the fault state of undervoltage or overvoltage caused by feedback failure, in addition to using hot-swap circuit protection, a power monitoring chip will be added to the circuit for over-voltage and under-voltage monitoring protection. When an overvoltage or undervoltage fault occurs, the fault signal will be input to the CPU controller, and then the controller will issue an instruction to close the circuit switch to protect the subsequent circuit chip and effectively prevent fault safety accidents.

[0006] The above-mentioned prior art has a voltage monitoring function in its circuit architecture, which uploads the overvoltage or undervoltage fault to the controller, and then issues a protection instruction after making a logical judgment to shut down the faulty circuit. However, the prior art still has the following deficiencies, such as:

[0007] ① The reaction takes a long time and it is easy to miss the best protection time;

[0008] ② It has overvoltage monitoring and fault self-locking functions, but lacks undervoltage monitoring function. When the equipment is undervoltage, it will still affect the life of the equipment;

[0009] ③ Even if it has over-voltage and under-voltage protection functions, such as hot-swap circuits, but there is no self-locking circuit, when overvoltage occurs, the circuit cuts off the power supply to the subsequent stage. After the overvoltage signal disappears, the circuit is closed again and the power supply is started. When the voltage is always at the threshold, the circuit will be repeatedly turned off and on, causing the equipment to malfunction and be in an unstable state. In addition, some circuits cannot monitor small voltage and undervoltage faults, resulting in reduced product safety. Summary of the invention

[0010] In order to solve the above technical problems, the present invention provides a hardware power supply over- and under-voltage monitoring and fault self-locking circuit at each level. After a fault, the circuit is automatically locked and disconnected immediately. Multiple voltages can be monitored. The over- and under-voltage monitoring thresholds can be set according to design requirements. It has voltage self-monitoring and can also avoid the fault of the product being unable to start normally due to overall undervoltage at the moment of power-on when monitoring a small voltage. When an over- or under-voltage fault occurs, the total input power supply will be cut off immediately, and the fault must be eliminated and the power must be restarted before it can work normally again, effectively protecting the subsequent circuits, achieving product-oriented safety, and preventing safety accidents.

[0011] A hardware power supply over-voltage and under-voltage monitoring circuit for each level and a fault self-locking circuit, comprising:

[0012] Reference power supply, over-voltage and under-voltage monitoring circuit, isolation circuit, delay circuit, self-locking circuit and power-off circuit; Among them:

[0013] The reference power supply is used to form a voltage reference source;

[0014] The over-voltage and under-voltage monitoring circuit is used to set monitoring thresholds for each level of power supply voltage and to perform over-voltage and under-voltage monitoring on the set monitoring thresholds;

[0015] The isolation circuit: plays the role of isolation and switching;

[0016] The delay circuit: when the device is powered on and the whole board is undervoltage, the over-voltage and undervoltage monitoring circuit can be controlled to be disabled. When the module is started normally, the over-voltage and undervoltage monitoring circuit can be turned on again.

[0017] The self-locking circuit is used to control the action of the power-off circuit;

[0018] The power-off circuit is used to directly cut off the primary power input terminal when an overvoltage or undervoltage fault occurs, to prevent damage to the subsequent circuit components, and to output an out-of-control signal to indicate an uncontrollable safety accident.

[0019] One end of the reference power supply is electrically connected to one end of the over-voltage and under-voltage monitoring circuit; the other end of the over-voltage and under-voltage monitoring circuit is electrically connected to one end of the isolation circuit; the other end of the isolation circuit is electrically connected to one end of the delay circuit; another end of the isolation circuit is electrically connected to one end of the self-locking circuit; the other end of the self-locking circuit is electrically connected to one end of the power-off circuit;

[0020] As an example, the reference power supply includes: R0, R1, D1 and C1, wherein R0 and R1 are connected in series to prevent failure of one of the resistors, resulting in damage to the diode D1. One end of the resistor R0 is connected to VCC, and the VCC is a primary power supply. After the diode D1 is connected in parallel with the capacitor C1, the anode is grounded; the cathode of the diode D1 is electrically connected to Vref, and the Vref is a high-precision reference voltage source that provides a voltage reference for the voltage comparator.

[0021] As an example, the over-voltage and under-voltage monitoring circuit includes: R2, R3, R4, R5, R6, R7, R8, R9, which are used as voltage adjustment resistors and can set monitoring thresholds according to the power supply voltages at various levels; and also includes: voltage comparators U1, U2, U3 and U4, which can perform over-voltage and under-voltage monitoring.

[0022] As a preferred example, the voltage comparator may also use an integrated multi-channel comparator or a single-channel comparator, and the most suitable solution may be selected according to design requirements.

[0023] As an example, the isolation circuit includes: optocoupler devices U5 and U6.

[0024] As an example, the delay circuit includes: R21, R22, R23, D2, Q6, U7, C5 and C6, the resistors R22 and R23 are connected in parallel and then connected to VCC, one end of the R21 is connected to the base of the transistor Q6, and the other end of the R21 is electrically connected to the RESET end of U7.

[0025] As an example, the self-locking circuit includes: Q4, Q5, R12, R13, R14, C3 and C4, one end of capacitor C4 is grounded, one end of resistor R13 is electrically connected to the base of transistor Q5, and one end of capacitor C3 is connected to VIN, and VIN is the input voltage of the power port of the hardware device module to provide the total power supply.

[0026] As an example, the power-off circuit includes: R15, R16, R17, R18, R20, C2, D2, Q1, Q2 and Q3, the resistors R15, R16 and the capacitor C2 are connected in parallel, the emitters of the transistors Q1 and Q2 are both grounded, one end of the resistor R20 is electrically connected to the base of the transistor Q2, and the other end of the resistor R20 is electrically connected to V_EN.

[0027] Beneficial effects of the present invention:

[0028] In the industrial control industry, it is necessary to monitor the voltage in real time. When an overvoltage or undervoltage fault occurs, the power supply must be cut off in time to protect the hardware equipment and effectively prevent safety accidents. The present invention can take action immediately when an overvoltage or undervoltage fault occurs, cut off the power circuit, avoid issuing protection instructions after logical judgment by the controller, shut down the faulty circuit, effectively prevent missing the optimal protection time, and maximize the protection of equipment safety and the safety of subsequent equipment. The operation can be monitored with or without a main control chip.

[0029] The present invention can monitor multiple passes and undervoltages simultaneously, and can monitor the power supply itself. No additional power supply is needed to monitor the primary power supply itself, thus effectively saving costs.

[0030] After the circuit over-voltage or under-voltage fault occurs, the circuit can be locked immediately, the power loop can be cut off, and the power must be re-powered before it can be started again. The self-locking circuit can effectively prevent the device from being in an unstable state of disconnection and shutdown when the over-voltage or under-voltage fluctuates near the threshold. Compared with the circuit in which the controller sends an unlocking signal, re-powering on can prevent misoperation caused by on-site electromagnetic interference and affect functional safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 The overall structure diagram of a hardware power supply over-voltage and under-voltage monitoring and fault self-locking circuit of the present invention.

[0032] Figure 2 This is a circuit principle design diagram of a hardware power supply over-voltage and under-voltage monitoring and fault self-locking circuit of the present invention. DETAILED DESCRIPTION

[0033] Below, reference Figure 1 to Figure 2 As shown, a hardware power supply over-voltage and under-voltage monitoring and fault self-locking circuit at each level includes:

[0034] Reference power supply, over-voltage and under-voltage monitoring circuit, isolation circuit, delay circuit, self-locking circuit and power-off circuit; Among them:

[0035] The reference power supply is used to form a voltage reference source;

[0036] The over-voltage and under-voltage monitoring circuit is used to set monitoring thresholds for each level of power supply voltage and to perform over-voltage and under-voltage monitoring on the set monitoring thresholds;

[0037] The isolation circuit: plays the role of isolation and switching;

[0038] The delay circuit: when the device is powered on and the whole board is undervoltage, the over-voltage and undervoltage monitoring circuit can be controlled to be disabled. When the module is started normally, the over-voltage and undervoltage monitoring circuit can be turned on again.

[0039] The self-locking circuit is used to control the action of the power-off circuit;

[0040] The power-off circuit is used to directly cut off the primary power input terminal when an overvoltage or undervoltage fault occurs, to prevent damage to the subsequent circuit components, and to output an out-of-control signal to indicate an uncontrollable safety accident.

[0041] One end of the reference power supply is electrically connected to one end of the over-voltage and under-voltage monitoring circuit; the other end of the over-voltage and under-voltage monitoring circuit is electrically connected to one end of the isolation circuit; the other end of the isolation circuit is electrically connected to one end of the delay circuit; another end of the isolation circuit is electrically connected to one end of the self-locking circuit; the other end of the self-locking circuit is electrically connected to one end of the power-off circuit;

[0042] As an example, the reference power supply includes: R0, R1, D1 and C1, wherein R0 and R1 are connected in series to prevent failure of one of the resistors, resulting in damage to the diode D1. One end of the resistor R0 is connected to VCC, and the VCC is a primary power supply. After the diode D1 is connected in parallel with the capacitor C1, the anode is grounded; the cathode of the diode D1 is electrically connected to Vref, and the Vref is a high-precision reference voltage source that provides a voltage reference for the voltage comparator.

[0043] As an example, the over-voltage and under-voltage monitoring circuit includes: R2, R3, R4, R5, R6, R7, R8, R9, which are used as voltage adjustment resistors and can set monitoring thresholds according to the power supply voltages at various levels; and also includes: voltage comparators U1, U2, U3 and U4, which can perform over-voltage and under-voltage monitoring.

[0044] As a preferred example, the voltage comparator may also use an integrated multi-channel comparator or a single-channel comparator, and the most suitable solution may be selected according to design requirements.

[0045] As an example, the isolation circuit includes: optocoupler devices U5 and U6.

[0046] As an example, the delay circuit includes: R21, R22, R23, D2, Q6, U7, C5 and C6, the resistors R22 and R23 are connected in parallel and then connected to VCC, one end of the R21 is connected to the base of the transistor Q6, and the other end of the R21 is electrically connected to the RESET end of U7.

[0047] As an example, the self-locking circuit includes: Q4, Q5, R12, R13, R14, C3 and C4, one end of capacitor C4 is grounded, one end of resistor R13 is electrically connected to the base of transistor Q5, and one end of capacitor C3 is connected to VIN, and VIN is the input voltage of the power port of the hardware device module to provide the total power supply.

[0048] As an example, the power-off circuit includes: R15, R16, R17, R18, R20, C2, D2, Q1, Q2 and Q3, the resistors R15, R16 and the capacitor C2 are connected in parallel, the emitters of the transistors Q1 and Q2 are both grounded, one end of the resistor R20 is electrically connected to the base of the transistor Q2, and the other end of the resistor R20 is electrically connected to V_EN.

[0049] As an example, the specification model used by U7 is: TPS3840DL30DBV.

[0050] As an example, V_EN can be understood as a control enable signal mark of a self-locking circuit, which is convenient for viewing the circuit principle and serves as a network signal mark.

[0051] In order to better illustrate the design principle of the present invention, the specific working principle of the circuit is introduced as follows:

[0052] 1. When the device is powered on, the delay circuit starts working. The delay time can be preset according to the device startup calculation time to control Q6 to be non-conductive. At this time, the optocoupler U6 is not conductive, the over-voltage and under-voltage monitoring circuits do not work, and the device can start normally.

[0053] 2. When the equipment starts normally, the over-voltage and under-voltage monitoring circuit starts to work. At this time, the set over-voltage and under-voltage thresholds are compared with the reference voltage of the reference power supply. When no over-voltage or under-voltage fault occurs, the voltage comparators U1, U2, U3 and U4 output high levels, and the optocoupler U5 is not conducting. At this time, in the power-off circuit, Q1 is turned on, Q2 is turned off, and the MOS switch of Q3 is controlled to open. The power supply can be input normally, providing the input voltage before isolation for the first-level power supply. At the same time, the first-level power supply provides input voltage for various small voltage conversion power supplies in the subsequent stage.

[0054] 3. When the equipment fails to provide feedback at the later stage, or an abnormal fault causes an overvoltage or undervoltage fault at one or more power supplies that exceeds the controllable safety threshold range, the overvoltage and undervoltage monitoring circuit will immediately output a low signal, and the optocoupler U5 will immediately turn on, causing VIN and V_EN to turn on. Q5 receives the base current and works in a saturation state, causing the Q4 transistor to operate and also operate in a saturation state. At this time, 24V_EN will operate at a high level. At this time, regardless of whether the optocoupler operates or not, V_EN will be clamped at VIN, directly closing the 24V switch and will not open it again unless the power is turned on again.

[0055] 4. Locking the power-off circuit (power-off switch) through the self-locking circuit can effectively avoid the situation where there is only an over-voltage or under-voltage monitoring circuit without a self-locking switch. When the over-voltage or under-voltage fluctuates within the threshold, the circuit will be in a repeated normal or abnormal state, and the output will be unstable. At the same time, it can avoid the situation where the controller sends a protection command after logical judgment and shuts off the faulty circuit, effectively preventing the best protection time from being missed, protecting the safety of the equipment and the subsequent equipment to the maximum extent, directly leading to safety, and effectively avoiding safety accidents.

[0056] As an example, as to why it is necessary to power on again to restart instead of using a control signal to unlock and open the self-locking circuit, this method is mainly to prevent extremely complex on-site conditions, where any interference signal may cause the unlocking signal to fluctuate, thereby causing the self-locking circuit to open, the power-off switch to close, and the overvoltage signal to instantly impact the subsequent circuit, possibly causing uncontrollable faults such as damage to the subsequent devices.

[0057] 5. At the same time, it can perform self-monitoring and monitor its own primary power supply. When an overvoltage or undervoltage fault occurs, it can be locked normally and the power-off circuit can be cut off. There is no need to design another power supply to monitor the primary power supply, which greatly saves the design complexity, is more concise, uses fewer devices, and saves costs.

[0058] 6. It can monitor multiple power supply voltages according to the internal voltage requirements of the equipment, which is more cost-effective.

[0059] As an example of the effect, in order to improve the accuracy of over-voltage and under-voltage monitoring and to design monitoring of any voltage according to needs, the voltage value can be set, the monitoring threshold range can be set, and self-power supply monitoring can be performed. It has a self-locking circuit, which will immediately lock after an over-voltage or under-voltage fault, cut off the power supply circuit, and prevent repeated startup and shutdown that affects stability. When an over-voltage or under-voltage fault occurs, there is no need to issue a protection command after the controller logic judgment to shut down the fault circuit, effectively preventing the best protection time from being missed and maximizing the protection of equipment safety and the safety of subsequent equipment.

[0060] The present invention can take immediate action and cut off the power supply circuit when an overvoltage or undervoltage fault occurs, avoid issuing a protection instruction after the controller logically judges, shut down the faulty circuit, effectively prevent missing the optimal protection time, and protect the safety of the equipment and the safety of the subsequent equipment to the maximum extent. The operation can be monitored with or without a main control chip; at the same time, multiple overvoltages and undervoltages can be monitored simultaneously, and self-power supply monitoring can be performed, and no additional power supply is required to monitor its own primary power supply, which effectively saves costs; after the circuit has an overvoltage or undervoltage fault, the circuit can be locked immediately, the power supply circuit can be cut off, and the power must be re-powered before it can be started again. The self-locking circuit can effectively prevent the device from being in an unstable state of being disconnected and closed when the overvoltage or undervoltage fluctuates near the threshold value, and compared with the circuit in which the controller sends an unlocking signal, re-powering on can prevent on-site electromagnetic interference from causing misoperation and affecting functional safety.

[0061] The above are only preferred embodiments of the present invention. It should be understood that the description of the above embodiments is only used to help understand the method and core ideas of the present invention, and is not used to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, etc. made within the ideas and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A hardware power supply over-voltage and under-voltage monitoring circuit and a fault self-locking circuit, characterized in that: include: Reference power supply, over-voltage and under-voltage monitoring circuit, isolation circuit, delay circuit, self-locking circuit and power-off circuit; Among them: The reference power supply is used to form a voltage reference source; The over-voltage and under-voltage monitoring circuit is used to set monitoring thresholds for each level of power supply voltage and to perform over-voltage and under-voltage monitoring on the set monitoring thresholds; The isolation circuit: plays the role of isolation and switching; The delay circuit: when the device is powered on and the whole board is undervoltage, the over-voltage and undervoltage monitoring circuit can be controlled to be disabled. When the module is started normally, the over-voltage and undervoltage monitoring circuit can be turned on again. The self-locking circuit is used to control the action of the power-off circuit; The power-off circuit is used to directly cut off the primary power input terminal when an overvoltage or undervoltage fault occurs, to prevent damage to subsequent circuit components, and to output an out-of-control signal to indicate the occurrence of an uncontrollable safety accident.

2. A hardware power supply over-voltage and under-voltage monitoring and fault self-locking circuit according to claim 1, characterized in that: One end of the reference power supply is electrically connected to one end of the over-voltage and under-voltage monitoring circuit; the other end of the over-voltage and under-voltage monitoring circuit is electrically connected to one end of the isolation circuit; the other end of the isolation circuit is electrically connected to one end of the delay circuit; another end of the isolation circuit is electrically connected to one end of the self-locking circuit; the other end of the self-locking circuit is electrically connected to one end of the power-off circuit.

3. A hardware power supply over-voltage and under-voltage monitoring and fault self-locking circuit according to claim 1, characterized in that: The reference power supply includes: R0, R1, D1 and C1, wherein R0 and R1 are connected in series to prevent failure of one of the resistors, resulting in damage to the diode D1. One end of the resistor R0 is connected to VCC, which is a primary power supply. After the diode D1 is connected in parallel with the capacitor C1, the anode is grounded. The cathode of the diode D1 is electrically connected to Vref, which is a high-precision reference voltage source and provides a voltage reference for the voltage comparator.

4. A hardware power supply over-voltage and under-voltage monitoring and fault self-locking circuit according to claim 1, characterized in that: The over-voltage and under-voltage monitoring circuit includes: R2, R3, R4, R5, R6, R7, R8, and R9, which are used as voltage regulating resistors and can set monitoring thresholds according to power supply voltages at various levels; and also includes: voltage comparators U1, U2, U3, and U4, which can perform over-voltage and under-voltage monitoring.

5. A hardware power supply over-voltage and under-voltage monitoring and fault self-locking circuit according to claim 1, characterized in that: The voltage comparator uses an integrated multi-channel comparator or a single-channel comparator, which is selected according to design requirements.

6. A hardware power supply over-voltage and under-voltage monitoring and fault self-locking circuit according to claim 1, characterized in that: The isolation circuit includes: optocoupler devices U5 and U6.

7. A hardware power supply over-voltage and under-voltage monitoring and fault self-locking circuit according to claim 1, characterized in that: The delay circuit includes: R21, R22, R23, D2, Q6, U7, C5 and C6, the resistors R22 and R23 are connected in parallel and then connected to VCC, one end of the R21 is connected to the base of the transistor Q6, and the other end of the R21 is electrically connected to the RESET end of U7.

8. A hardware power supply over-voltage and under-voltage monitoring and fault self-locking circuit according to claim 1, characterized in that: The self-locking circuit includes: Q4, Q5, R12, R13, R14, C3 and C4, one end of the capacitor C4 is grounded, one end of the resistor R13 is electrically connected to the base of the transistor Q5, and one end of the capacitor C3 is connected to VIN. The VIN is the input voltage of the power port of the hardware device module to provide the total power supply.

9. A hardware power supply over-voltage and under-voltage monitoring and fault self-locking circuit according to claim 1, characterized in that: The power-off circuit includes: R15, R16, R17, R18, R20, C2, D2, Q1, Q2 and Q3. The resistors R15, R16 and the capacitor C2 are connected in parallel. The emitters of the transistors Q1 and Q2 are both grounded. One end of the resistor R20 is electrically connected to the base of the transistor Q2, and the other end of the resistor R20 is electrically connected to V_EN.

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