CN220137350U - Load fault detection circuit - Google Patents
Load fault detection circuit Download PDFInfo
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- CN220137350U CN220137350U CN202321384154.6U CN202321384154U CN220137350U CN 220137350 U CN220137350 U CN 220137350U CN 202321384154 U CN202321384154 U CN 202321384154U CN 220137350 U CN220137350 U CN 220137350U
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- 238000001514 detection method Methods 0.000 title claims abstract description 62
- 239000003990 capacitor Substances 0.000 claims description 8
- 230000002035 prolonged effect Effects 0.000 abstract description 2
- 238000005070 sampling Methods 0.000 description 5
- 238000010586 diagram Methods 0.000 description 4
- 238000000034 method Methods 0.000 description 3
- 238000003199 nucleic acid amplification method Methods 0.000 description 2
- 230000002159 abnormal effect Effects 0.000 description 1
- 230000003321 amplification Effects 0.000 description 1
- 238000012938 design process Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
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Abstract
The utility model discloses a load fault detection circuit, which comprises: the current limiting unit is used for judging the open circuit of the power load switch unit in the OFF mode; the MCU is used for receiving the current value and the voltage value of the current load, so that the working state of the load can be judged, and the current limiting unit and the current detecting unit can be controlled; the current detection unit is used for detecting the voltage corresponding to the load current value in real time, transmitting the voltage to the MCU unit and calculating the load current according to the proportion coefficient through the MCU unit; the voltage detection unit is used for detecting the voltage value of the load in real time and transmitting the voltage value of the load to the MCU unit. The MCU unit is used for judging the current load working state by acquiring the current voltage and current value of the load and combining with the ON/OFF mode, the MCU unit is used for judging the load through the state to monitor the load, so that a plurality of branch circuits are avoided, the circuit complexity is reduced, the reliability, the safety and the effectiveness of the load operation are improved, the failure loss rate is reduced, and the service life of the load can be effectively prolonged.
Description
Technical Field
The utility model relates to the technical field of load fault detection, in particular to a load fault detection circuit.
Background
Modern automobile electronic loads have higher and higher safety requirements, so that the real-time monitoring of the working states of all loads in the vehicle is particularly important. The load fault detection can timely diagnose the abnormal states of overcurrent, overvoltage, short circuit and open circuit, thereby achieving the purpose of preventing or eliminating faults, and the traditional load fault detection is limited to single fault detection, such as single open circuit detection circuit, single overcurrent detection circuit and overvoltage detection circuit, and has more discrete devices and a plurality of branch circuits, so that the circuit is complex.
Disclosure of Invention
In order to solve the technical problems in the background technology, the utility model provides a load fault detection circuit.
The utility model provides a load fault detection circuit, which comprises:
the current limiting unit is used for judging the open circuit of the power load switch unit in the OFF mode;
the MCU unit is used for receiving the current value and the voltage value of the current load and simultaneously combining with the ON/OFF mode so as to judge the working state of the load and control the use of the current limiting unit and the current detecting unit;
the current detection unit is used for detecting the voltage corresponding to the load current value in real time, transmitting the voltage to the MCU unit and calculating the load current according to the proportion coefficient through the MCU unit;
the voltage detection unit is used for detecting the voltage value of the load in real time and transmitting the voltage value of the load to the MCU unit;
power supplyThe load switch unit comprises an MOS tube and a feedback circuit, wherein the MOS tube is a load main current loop; the feedback circuit is used for measuring the current value I passing through the MOS tube L I.e. load current, while the feedback circuit can supply I L The feedback current I after the reduction can be reduced according to a certain proportion S Transmitting to a current detection unit;
the output end of the MCU unit is electrically connected with the input ends of the current limiting unit and the power load switch unit respectively, the input end of the MCU unit is electrically connected with the output end of the current detection unit and the output end of the voltage detection unit respectively, the input end of the current detection unit is electrically connected with the output end of the power load switch unit, and the input end of the voltage detection unit is electrically connected with the load.
Preferably, the voltage detection unit includes an operational amplifier U1A, an operational amplifier U1B, and a first-order filter circuit, wherein an output end of the operational amplifier U1A is electrically connected to a "+" input end of the operational amplifier U1B through the first-order filter circuit, and a resistor R1 is disposed between the output end of the operational amplifier U1A and the "-" input end of the operational amplifier U1A.
Preferably, the "-" input end of the operational amplifier U1A is provided with a resistor R2, and the other end of the resistor R2 is grounded, the "+" input end of the operational amplifier U1A is provided with a resistor R4 and a resistor R5, and the other end of the resistor R4 is electrically connected to the load, the other end of the resistor R5 is grounded, and the output end of the operational amplifier U1B is electrically connected to the "-" input end of the operational amplifier U1B.
Preferably, the output end of the operational amplifier U1B is electrically connected with the positive electrode of the diode D1, the negative electrode of the diode D1 is connected with the power VCC, the positive electrode of the diode D1 is electrically connected with the negative electrode of the diode D2, the positive electrode of the diode D2 is grounded, and the power end of the operational amplifier U1A is provided with the capacitor C1.
Preferably, the current detection unit includes an operational amplifier U2A, an operational amplifier U2B, and a second first-order filter circuit, wherein an output end of the operational amplifier U2A is electrically connected to a "+" input end of the operational amplifier U2B through the second first-order filter circuit, and a resistor R6 is disposed between the output end of the operational amplifier U2A and the "-" input end of the operational amplifier U1A.
Preferably, the "-" input end of the operational amplifier U2A is provided with a resistor R7, the other end of the resistor R7 is grounded, the "+" input end of the operational amplifier U2A is provided with a resistor R9 and a resistor R10, the resistor R9 and the resistor R10 are connected in series, the other end of the resistor R10 is grounded, and the output end of the operational amplifier U2B is electrically connected with the "-" input end of the operational amplifier U2B.
Preferably, the output end of the operational amplifier U2B is electrically connected with the positive electrode of the diode D3, the negative electrode of the diode D3 is connected with the power VCC, the positive electrode of the diode D3 is electrically connected with the negative electrode of the diode D4, the positive electrode of the diode D4 is grounded, and the power end of the operational amplifier U2A is provided with the capacitor C3.
In the load fault detection circuit provided by the utility model, when the power load switch unit is in an OFF mode, the MCU unit supplies 1mA current to the later-stage load through the current limiting unit, and is combined with the voltage detection circuit, if the load is in an open circuit state at the moment, the MCU unit detects that the output voltage is Vbb, and if the load is normally connected at the moment, the MCU unit detects that the output voltage is less than Vbb. The circuit can realize the detection of the lowest 1mA load open circuit. When the power load switch unit is in the ON mode, the MCU unit detects the current feedback output I S The value is used for judging whether the load has an open circuit or not, the MCU judges the working state of the current load by acquiring the current voltage and current value of the load and combining with the ON/OFF mode, and the MCU monitors the load by judging the state, so that a plurality of branch circuits are avoided, the complexity of the circuit is reduced, the reliability, the safety and the effectiveness of the load operation are improved, the failure loss rate is reduced, and the service life of the load can be effectively prolonged.
Drawings
Fig. 1 is a schematic structural diagram of a hardware architecture of a load fault detection circuit according to the present utility model;
fig. 2 is a schematic diagram of a current limiting unit of a load fault detection circuit according to the present utility model;
fig. 3 is a schematic diagram of a voltage detection unit of a load fault detection circuit according to the present utility model;
fig. 4 is a schematic structural diagram of a current detecting unit of a load fault detecting circuit according to the present utility model.
Detailed Description
Referring to fig. 1 and 2, a load fault detection circuit according to the present utility model includes:
the current limiting unit is used for judging the open circuit of the power load switch unit in the OFF mode;
the MCU unit is used for receiving the current value and the voltage value of the current load and simultaneously combining with the ON/OFF mode so as to judge the working state of the load and control the use of the current limiting unit and the current detecting unit;
it should be further noted that, the power load switch unit and the current limiting unit are both in the OFF mode, the load voltage is at low level, the feedback current value is 0, and the load state is normal; the power load switch unit is in an ON mode, the current limiting unit is in an OFF mode, the load voltage is high level, and the feedback current value is I S The load state is normal; the power load switch unit is in an ON mode, the current limiting unit is in an OFF mode, the load voltage is high level, and the feedback current value is greater than or equal to I lim The load state is overcurrent; the power load switch unit and the current limiting unit are in an OFF mode, the load voltage and the feedback current value are 0, and the load state is short-circuited to the ground; the power load switch unit is in an ON mode, the current limiting unit is in an OFF mode, the load voltage is low level, and the feedback current value is greater than or equal to I lim The load state is short-circuited to ground; the power load switch unit and the current limiting unit are both in an OFF mode, the load voltage is high level, the feedback current value is 0, and the load state is overvoltage; the power load switch unit is in an ON mode, the current limiting unit is in an OFF mode, the load voltage is larger than Vbb, and the load state is overvoltage; the power load switch unit is in an ON mode, the current limiting unit is in an OFF mode, the load voltage is high level, the feedback current value is 0, and the load state is open circuit; the power load switch unit is in an OFF mode, the current limiting unit is in an ON mode, and the load is poweredThe voltage is high level, and the load state is open circuit; wherein I is S Is the feedback current value; i lim The overcurrent point set for the MCU unit can be customized according to the actual application of the overcurrent point; the high level and the low level are voltage judgment values set by the MCU, and can be customized according to practical application.
The current detection unit is used for detecting the voltage corresponding to the load current value in real time, transmitting the voltage to the MCU unit and calculating the load current according to the proportion coefficient through the MCU unit;
the voltage detection unit is used for detecting the voltage value of the load in real time and transmitting the voltage value of the load to the MCU unit;
the power load switch unit comprises an MOS tube and a feedback circuit, wherein the MOS tube is a load main current loop; the feedback circuit is used for measuring the current value I passing through the MOS tube L I.e. load current, and the feedback circuit can reduce IL according to a certain proportion, and can reduce the feedback current I S Transmitting to a current detection unit;
the output end of the MCU unit is electrically connected with the input ends of the current limiting unit and the power load switch unit respectively, the input end of the MCU unit is electrically connected with the output end of the current detection unit and the output end of the voltage detection unit respectively, the input end of the current detection unit is electrically connected with the output end of the power load switch unit, and the input end of the voltage detection unit is electrically connected with the load.
It should be further noted that, when the power load switch unit is in the OFF mode, the MCU unit provides 1mA current to the load at the rear stage through the current limiting unit, and in combination with the voltage detection circuit, if the load is in the open state at this time, the MCU unit detects that the output voltage is at a high level, and if the load is normally connected at this time, the MCU unit detects that the output voltage is at a low level. The circuit can realize the detection of the lowest 1mA load open circuit. When the power load switch unit is in the ON mode, the MCU unit detects the current feedback output I S The value thus determines that the load is free of open circuits.
The MCU unit judges the working state of the current load by acquiring the current voltage and current value of the load and combining the ON/OFF mode, and monitors the load by judging the state and uploads data to the upstream load, so that fault damage is effectively avoided.
Specifically, as shown in fig. 3, the voltage detection unit includes an operational amplifier U1A, an operational amplifier U1B, and a first-order filter circuit, where an output end of the operational amplifier U1A is electrically connected to a "+" input end of the operational amplifier U1B through the first-order filter circuit, a resistor R1 is disposed between the output end of the operational amplifier U1A and a "-" input end of the operational amplifier U1A, the "-" input end of the operational amplifier U1A is disposed with a resistor R2, and the other end of the resistor R2 is grounded, the "+" input end of the operational amplifier U1A is disposed with a resistor R4 and a resistor R5, and the other end of the resistor R4 is electrically connected to a load, the output end of the operational amplifier U1B is electrically connected to the "-" input end of the operational amplifier U1B, the negative electrode of the diode D1 is connected to a power VCC, the positive electrode of the diode D1 is electrically connected to the negative electrode of the diode D2, and the positive electrode of the diode D1 is grounded, and the positive electrode of the operational amplifier C1 is disposed with a capacitor.
It should be further noted that, the voltage/current sampling design is performed by using an operational amplifier, the operational amplifier selects rail-to-rail, low-bias and low-noise devices, the gain is kept adjustable in the design process, the gain can be adjusted according to the external voltage/current input range and the ADC sampling voltage input range, and meanwhile, the signal input impedance becomes very high, the output impedance becomes very low, and the noise input of the signal and the attenuation of the signal are reduced by adopting a two-stage voltage following design.
Specifically, the voltage sampling process: the load voltage reaches the U1A positive input end V+ through the partial pressure of R4 and R5 at firstThen U1A in-phase amplification is carried out>Multiple times of the current reaches the output end of U1AThe non-inverting input follows through U1B to the U1B output where u1a_vout=u1b_vout=vout_v.
According to the working mode, the method comprises the following steps of:the resistor R3 and the capacitor C2 form a first-order filter circuit, noise is filtered, and signal quality is improved. The diodes D1 and D2 are clamping circuits, and the voltage of the MCU sampling port is protected from exceeding the working limit value.
Specifically, as shown in fig. 4, the current detection unit includes an operational amplifier U2A, an operational amplifier U2B, and a second first-order filter circuit, the output end of the operational amplifier U2A is electrically connected to the "+" input end of the operational amplifier U2B through the second first-order filter circuit, a resistor R6 is disposed between the output end of the operational amplifier U2A and the "-" input end of the operational amplifier U1A, the "-" input end of the operational amplifier U2A is provided with a resistor R7, the other end of the resistor R7 is grounded, the "+" input end of the operational amplifier U2A is provided with a resistor R9 and a resistor R10, the other end of the resistor R10 is grounded, the output end of the operational amplifier U2B is electrically connected to the "-" input end of the operational amplifier U2B, the negative electrode of the diode D3 is connected to the power VCC, the positive electrode of the diode D3 is electrically connected to the negative electrode of the diode D4, and the positive electrode of the diode D2A is grounded, and the positive electrode of the capacitor C2A is connected to the positive electrode of the operational amplifier U2A.
It should be further noted that the current is first converted into a voltage signal by resistor R10 to reach the U2A positive input terminal V+, where V + =sen_in_i×r10, and then subjected to U2A IN-phase amplificationMultiple times of the current reaches the U2A output endThe non-inverting input follows through U2B to the U2B output where u2a_vout=u2b_vout=vout_i.
According to the above workMode calculation:the resistor R8 and the capacitor C4 form a second first-order filter circuit, noise is filtered, and signal quality is improved. The diode D3 and the diode D4 are clamping circuits, and the voltage of the MCU sampling port is protected from exceeding the working limit value.
In a specific working process of the load fault detection circuit of the embodiment, when the power load switch unit is in an OFF mode, the MCU unit provides 1mA current for a later stage load through the current limiting unit, and in combination with the voltage detection circuit, if the load is in an open state at this time, the MCU unit detects that the output voltage is Vbb, and if the load is normally connected at this time, the MCU unit detects that the output voltage is below Vbb. The circuit can realize the detection of the lowest 1mA load open circuit. When the power load switch unit is in the ON mode, the MCU unit detects the current feedback output I S The value thus determines that the load is free of open circuits.
The foregoing is only a preferred embodiment of the present utility model, but the scope of the present utility model is not limited thereto, and any person skilled in the art, who is within the scope of the present utility model, should make equivalent substitutions or modifications according to the technical scheme of the present utility model and the inventive concept thereof, and should be covered by the scope of the present utility model.
Claims (7)
1. A load fault detection circuit, comprising:
the current limiting unit is used for judging the open circuit of the power load switch unit in the OFF mode;
the MCU unit is used for receiving the current value and the voltage value of the current load and simultaneously combining with an ON/OFF mode so as to judge the working state of the load and control the use of the current limiting unit and the current detecting unit;
the current detection unit is used for detecting the voltage corresponding to the load current value in real time, transmitting the voltage to the MCU unit and calculating the load current according to the proportion coefficient through the MCU unit;
the voltage detection unit is used for detecting the voltage value of the load in real time and transmitting the voltage value of the load to the MCU unit;
the power load switch unit comprises an MOS tube and a feedback circuit, wherein the MOS tube is a load main current loop; the feedback circuit is used for measuring the current value I passing through the MOS tube L I.e. load current, while the feedback circuit can supply I L Reducing according to a certain proportion, and feeding back the reduced feedback current I S Transmitting to a current detection unit;
the output end of the MCU unit is electrically connected with the input ends of the current limiting unit and the power load switch unit respectively, the input end of the MCU unit is electrically connected with the output end of the current detection unit and the output end of the voltage detection unit respectively, the input end of the current detection unit is electrically connected with the output end of the power load switch unit, and the input end of the voltage detection unit is electrically connected with the load.
2. The load fault detection circuit according to claim 1, wherein the voltage detection unit includes an operational amplifier U1A, an operational amplifier U1B, and a first-order filter circuit, an output terminal of the operational amplifier U1A is electrically connected to a "+" input terminal of the operational amplifier U1B through the first-order filter circuit, and a resistor R1 is disposed between the output terminal of the operational amplifier U1A and the "-" input terminal of the operational amplifier U1A.
3. The load fault detection circuit according to claim 2, wherein a resistor R2 is disposed at an "-" input end of the operational amplifier U1A, and the other end of the resistor R2 is grounded, a resistor R4 and a resistor R5 are disposed at an "+" input end of the operational amplifier U1A, and the other end of the resistor R4 is electrically connected to the load, and the other end of the resistor R5 is grounded, and an output end of the operational amplifier U1B is electrically connected to the "-" input end of the operational amplifier U1B.
4. The load fault detection circuit of claim 3, wherein the output terminal of the operational amplifier U1B is electrically connected to the positive electrode of the diode D1, the negative electrode of the diode D1 is connected to the power source VCC, the positive electrode of the diode D1 is electrically connected to the negative electrode of the diode D2, and the positive electrode of the diode D2 is grounded, and the power source terminal of the operational amplifier U1A is provided with the capacitor C1.
5. The load fault detection circuit according to claim 1, wherein the current detection unit includes an operational amplifier U2A, an operational amplifier U2B, and a second first-order filter circuit, an output terminal of the operational amplifier U2A is electrically connected to a "+" input terminal of the operational amplifier U2B through the second first-order filter circuit, and a resistor R6 is disposed between the output terminal of the operational amplifier U2A and the "-" input terminal of the operational amplifier U1A.
6. The load fault detection circuit according to claim 5, wherein a resistor R7 is disposed at the "-" input of the operational amplifier U2A, the other end of the resistor R7 is grounded, a resistor R9 and a resistor R10 are disposed at the "+" input of the operational amplifier U2A, the resistor R9 and the resistor R10 are connected in series, the other end of the resistor R10 is grounded, and the output end of the operational amplifier U2B is electrically connected to the "-" input of the operational amplifier U2B.
7. The load fault detection circuit according to claim 6, wherein the output terminal of the operational amplifier U2B is electrically connected to the positive electrode of the diode D3, the negative electrode of the diode D3 is connected to the power source VCC, the positive electrode of the diode D3 is electrically connected to the negative electrode of the diode D4, the positive electrode of the diode D4 is grounded, and the power source terminal of the operational amplifier U2A is provided with the capacitor C3.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202321384154.6U CN220137350U (en) | 2023-05-31 | 2023-05-31 | Load fault detection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202321384154.6U CN220137350U (en) | 2023-05-31 | 2023-05-31 | Load fault detection circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN220137350U true CN220137350U (en) | 2023-12-05 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202321384154.6U Active CN220137350U (en) | 2023-05-31 | 2023-05-31 | Load fault detection circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN220137350U (en) |
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2023
- 2023-05-31 CN CN202321384154.6U patent/CN220137350U/en active Active
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