Question 1

Sensor common problems and solutions

Accepted Answer

Problem One: Calibration Drift in Pressure Sensors

Cause: Condensation on the pressure sensor may invalidate the established calibration, or "calibration drift"

Solution: Select a pressure sensor with calibration drift in environments where instrument calibration is necessary and calibration validity needs to be ensured

Problem 2: There is a problem with the oxygen sensor of the car due to low fuel quality or improper maintenance

Cause: The driver uses gasoline that is not recommended or low-quality gasoline, and the life of the oxygen sensor may also be lower than the expected average life

Solution: Proactive consideration and early prevention can reduce sensor failure

Question 2

Common problems and solutions of MOSFET tubes

Accepted Answer

Problem 1: Voltage failure

Cause: A common failure mode caused by the MOSFET drain-source voltage exceeding its specified voltage value and reaching a certain energy limit

Solution: 1. Reasonable derating use, 2. Reasonable transformer reflection voltage, 3: Reasonable RCD and TVS absorption circuit design, 4: Large current wiring should adopt thick and short layout structure to minimize wiring parasitic inductance, 5 : Choose a reasonable gate resistor Rg, 6: In high-power power supply, you can add RC shock absorber or Zener diode to absorb

Problem 2: Electrostatic failure

Causes: absorb dust, change the impedance between lines, due to the action of electric field or current, the insulation layer and conductor of the component are damaged, so that the component cannot work (completely damaged), due to the instantaneous soft breakdown of the electric field or overheating of the current, the component is damaged damage

Solution: The protection diode at the input of the MOS circuit has a current tolerance of 1 mA when powered. When there may be too large instantaneous input current (greater than 10mA), the input protection resistor should be connected in series. At the same time, due to the limited instantaneous energy absorbed by the protection circuit, excessive transient signals and excessive electrostatic voltage will cause the protection circuit to fail. Therefore, during the soldering process, the soldering iron must be reliably grounded to prevent leakage from the input terminals of the equipment. In general use, after the power is cut off, the residual heat of the soldering iron can be used for soldering, and the grounding pin should be soldered first.

Question 3: Current failure

Cause: It refers to the destruction mode caused by the abnormal high current and voltage superimposed on the MOSFET at the same time when the power supply is running, resulting in instantaneous local heating

Solution: 1: Limited by the maximum rated current and pulse current

2: RDSON limited by maximum junction temperature.

3: Limited by the maximum power dissipation of the device.

4: Limited by the maximum single pulse current.

5: Breakdown voltage BVDSS restricted area

Question 3

Common problems and solutions of rectifier diodes

Accepted Answer

Problem 1: Inefficiency

Cause: It is caused by improper circuit design, current limitation or damage of the diode itself

Solution: Reprogram the circuit and make sure to use a compliant diode

Question 2: Leakage problem

Cause: due to defects in diode materials or due to long-term use

Solution: Use qualified diodes and strictly implement circuit design and usage specifications

Question 3: Temperature Problem

Cause: In a high temperature environment, the diode is prone to failure or deformation

Solution: Choose a diode suitable for temperature conditions and take effective heat dissipation measures

Question 4: Noise Problem

Cause: It may be caused by manufacturing process, poor material quality or circuit interference

Solution: Select diodes that meet the requirements, and take effective circuit isolation and filtering measures

Question 4

Causes and solutions of MLCC howling

Accepted Answer

Cause:
MLCC vibrates with a large amplitude under the action of voltage, and the formed electrostriction will whistle

Solution:
1. Thicken the bottom protective layer

2. Additional metal bracket structure

FAQ Category

FAQ

Q Sensor common problems and solutions

Q Common problems and solutions of MOSFET tubes

Q Common problems and solutions of rectifier diodes

Q Causes and solutions of MLCC howling

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