Open circuit and short circuit fault detection circuit without interference to signal source
By designing a simple constant current source excitation circuit and comparator circuit, open circuit and short circuit faults of piezoelectric accelerometers are detected, solving the problem of detecting complex and interfering signal sources in the prior art and realizing interference-free fault detection.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-14
- Publication Date
- 2026-03-03
AI Technical Summary
Existing technologies struggle to detect both open-circuit and short-circuit faults in piezoelectric accelerometers simultaneously without interfering with the signal source, and often require complex logic circuits.
A simple detection circuit was designed, consisting of a constant current source excitation circuit, a capacitor, a clamping diode, a resistor, and a comparator. This circuit distinguishes between open-circuit and short-circuit faults by detecting voltage changes in the circuit, thus avoiding interference with the signal source.
It enables simple detection of open-circuit and short-circuit faults in piezoelectric accelerometers without affecting the normal operation of the signal source.
Smart Images
Figure CN223966685U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of sensor open circuit and short circuit fault detection technology, and in particular to an open circuit and short circuit fault detection circuit that does not interfere with the signal source. Background Technology
[0002] A piezoelectric accelerometer is a device that uses piezoelectric materials as conversion elements to transform an acceleration input into a proportional charge or voltage output. It features high sensitivity, wide bandwidth, and good stability in vibration monitoring and dynamic testing, and is commonly used in industrial equipment, structural health monitoring, aerospace, and other fields. The charge or voltage signal output by the piezoelectric accelerometer needs to be converted by a signal conditioning circuit before entering the data acquisition, analysis, and control module. When a piezoelectric accelerometer malfunctions, it will fail, unable to output a signal, affecting its use. Therefore, it is necessary to detect sensor faults to ensure reliability and promptly troubleshoot problems. Piezoelectric accelerometers typically experience open-circuit and short-circuit faults. Simultaneous detection of both open-circuit and short-circuit faults usually requires complex logic circuitry and may also cause interference to the sensor's signal source. Summary of the Invention
[0003] This invention provides an open-circuit and short-circuit fault detection circuit that does not interfere with the signal source. This circuit can detect open-circuit and short-circuit faults in piezoelectric accelerometers. The circuit is simple and does not cause any interference to the signal source.
[0004] To solve the above-mentioned technical problems, the technical solution of this utility model is as follows:
[0005] An open-circuit and short-circuit fault detection circuit that does not interfere with the signal source is connected between a piezoelectric accelerometer and a signal processing circuit. The open-circuit and short-circuit fault detection circuit includes a constant current source excitation circuit, a first capacitor, a clamping diode, a first resistor, a second resistor, a third resistor, a fourth resistor, a first comparator, and a second comparator. The constant current source excitation circuit includes a constant current source connected to the signal output terminal of the piezoelectric accelerometer. The first capacitor is connected between the constant current source excitation circuit and the signal processing circuit. The clamping diode, the first resistor, the first comparator, and the second comparator are connected in parallel. The cathode of the clamping diode... One end of the first resistor, the negative input of the first comparator, and the non-inverting input of the second comparator are all connected to the constant current source excitation circuit. The anode of the clamping diode and the other end of the first resistor are both grounded. The second, third, and fourth resistors are connected in series. The non-inverting input of the first comparator is connected between the second and third resistors. The other end of the second resistor is connected to the comparator power supply. The negative input of the second comparator is connected between the third and fourth resistors. The other end of the fourth resistor is grounded. When the output of the first comparator is low, there is an open circuit fault. When the output of the second comparator is low, there is a short circuit fault.
[0006] The resistance of the first resistor is 1 to 10 MΩ, the resistance of the second resistor is 7.5 to 150 KΩ, the resistance of the third resistor is 5 to 50 KΩ, and the resistance of the fourth resistor is 1 to 10 KΩ.
[0007] The resistance ratio of the second, third, and fourth resistors is 15:10:2.
[0008] The voltage of the comparator power supply is 5 to 18V.
[0009] Compared with the prior art, the beneficial effects of this utility model are: the open circuit and short circuit fault detection circuit provided by this utility model can detect open circuit and short circuit faults of piezoelectric accelerometers without interference to the signal source. The circuit is simple and will not cause any interference to the signal source. Attached Figure Description
[0010] Figure 1 This is a connection diagram of the open-circuit and short-circuit fault detection circuit that does not interfere with the signal source provided by this utility model. Detailed Implementation
[0011] The present invention will be further described below with reference to the accompanying drawings and embodiments.
[0012] The open-circuit and short-circuit fault detection circuit provided in this embodiment, which does not interfere with the signal source, is connected between the piezoelectric accelerometer and the signal processing circuit. It detects open-circuit and short-circuit faults in the piezoelectric accelerometer without interfering with the signal source. Figure 1 As shown.
[0013] In this embodiment, the open-circuit and short-circuit fault detection circuit that does not interfere with the signal source includes a constant current source excitation circuit, a first capacitor C1, a clamping diode TVS, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a first comparator, and a second comparator. The constant current source excitation circuit includes a constant current source connected to the signal output terminal of the piezoelectric accelerometer. The constant current source excites the piezoelectric accelerometer to generate a DC bias voltage of 9-12V, while superimposing the sensor's own ±5-10V output signal.
[0014] The first capacitor C1 is connected between the constant current source excitation circuit and the signal processing circuit. The clamping diode TVS, the first resistor R1, the first comparator and the second comparator are connected in parallel. The cathode of the clamping diode TVS, one end of the first resistor R1, the negative input terminal of the first comparator and the non-inverting input terminal of the second comparator are all connected to the constant current source excitation circuit. The anode of the clamping diode TVS and the other end of the first resistor R1 are both grounded.
[0015] The second resistor R2, the third resistor R3, and the fourth resistor R4 are connected in series. The non-inverting input of the first comparator is connected between the second resistor R2 and the third resistor R3. The other end of the second resistor R2 is connected to the comparator power supply, which has a voltage of 5–18V. The negative input of the second comparator is connected between the third resistor R3 and the fourth resistor R4. The other end of the fourth resistor R4 is grounded. When the output of the first comparator is low, an open circuit fault exists; when the output of the second comparator is low, a short circuit fault exists.
[0016] In this embodiment, the resistance of the first resistor R1 is 1–10 MΩ, the resistance of the second resistor R2 is 7.5–150 KΩ, the resistance of the third resistor R3 is 5–50 KΩ, and the resistance of the fourth resistor R4 is 1–10 KΩ. Preferably, the resistance ratio of the second resistor R2, the third resistor R3, and the fourth resistor R4 is 15:10:2. The clamping voltage of the clamping diode TVS is set to 24V. When the piezoelectric accelerometer is open-circuited, the voltage across the first resistor R1 is the clamping voltage of the TVS, i.e., 24V. At this time, the first comparator outputs a low level, and the second comparator outputs a high level. When the piezoelectric accelerometer is short-circuited, the voltage across the first resistor R1 tends to 0V, the first comparator outputs a high level, and the second comparator outputs a low level. When the piezoelectric accelerometer is working normally, the first resistor R1 generates a DC bias that is superimposed on the bias voltage of the piezoelectric accelerometer. After passing through the subsequent filter capacitor (the first capacitor), the DC bias voltage is completely canceled out, so it will not cause any interference to the signal source.
Claims
1. An open-circuit and short-circuit fault detection circuit that does not interfere with the signal source, connected between a piezoelectric accelerometer and a signal processing circuit, characterized in that: The open-circuit and short-circuit fault detection circuit that does not interfere with the signal source includes a constant current source excitation circuit, a first capacitor, a clamping diode, a first resistor, a second resistor, a third resistor, a fourth resistor, a first comparator, and a second comparator. The constant current source excitation circuit includes a constant current source connected to the signal output terminal of the piezoelectric accelerometer. The first capacitor is connected between the constant current source excitation circuit and the signal processing circuit. The clamping diode, the first resistor, the first comparator, and the second comparator are connected in parallel. The cathode of the clamping diode, one end of the first resistor, the negative input terminal of the first comparator, and the non-inverting input terminal of the second comparator are all connected to the constant current source excitation circuit. The anode of the clamping diode and the other end of the first resistor are both grounded. The second, third, and fourth resistors are connected in series. The non-inverting input terminal of the first comparator is connected between the second and third resistors. The other end of the second resistor is connected to the comparator power supply. The negative input terminal of the second comparator is connected between the third and fourth resistors. The other end of the fourth resistor is grounded. When the output terminal of the first comparator outputs a low level, an open-circuit fault exists. When the output terminal of the second comparator outputs a low level, a short-circuit fault exists.
2. The open-circuit and short-circuit fault detection circuit that does not interfere with the signal source according to claim 1, characterized in that: The resistance of the first resistor is 1 to 10 MΩ, the resistance of the second resistor is 7.5 to 150 KΩ, the resistance of the third resistor is 5 to 50 KΩ, and the resistance of the fourth resistor is 1 to 10 KΩ.
3. The open-circuit and short-circuit fault detection circuit that does not interfere with the signal source according to claim 1, characterized in that: The resistance ratio of the second, third, and fourth resistors is 15:10:
2.
4. The open-circuit and short-circuit fault detection circuit that does not interfere with the signal source according to claim 1, characterized in that: The voltage of the comparator power supply is 5 to 18V.