Automobile sensor protection circuit

Abstract

The invention discloses an automobile sensor protection circuit, which comprises an overvoltage control unit, a switch unit and an anti-reverse-connection unit, wherein the overvoltage control unit is connected among a power source power supplying end, a load grounding end and a control end of the switch unit, an input end of the switch unit is connected with the power source power supplying end, an output end of the switch unit is connected with a load power receiving end, the overvoltage control unit controls the on-off state of the switch unit according to the voltage change of the power source power supplying end, the anti-reverse-connection unit is connected among the power source power supplying end, a power source grounding end and a load grounding end, so that the damage to a load caused by the reverse connection of a power source and the load or negative voltage pulse can be avoided. The automobile sensor protection circuit has the advantages that the overvoltage protection and the reverse connection protection on an automobile sensor are realized, and the fault rate of the automobile sensor is reduced.

Description

technical field [0001] The invention relates to the field of automotive sensor circuit protection, in particular to an overvoltage protection circuit of an automotive pressure sensor. Background technique [0002] The instantaneous high-voltage pulse, negative pressure pulse or pulse group caused by external factors in the automotive circuit system will cause damage to the components in the circuit system, including damage to the sensor. For example, the automotive circuit system will generate high-voltage or negative-voltage pulses or pulse groups when the car is ignited or the motor on the car is turned on or off, although the power supply of the car (Electronic Control Unit, electronic control unit) and other electronic devices on the car is powered by DC -DC (DC-DC conversion) power supply, but the output of DC-DC power supply will still have residual high-voltage or negative voltage pulses or pulse groups, even if the amplitude of these pulses or pulse groups has been g...

AI Technical Summary

Problems solved by technology

[0003] The pressure sensors commonly used in automobiles include oil pressure sensors and MAP sensors (that is, intake manifold absolute pressure sensors). The normal operating voltage is 5±0.25V, but because of the existence of high pressure or negative pressure pulses, the pressure sensor will cause the chip to be adjusted. It is easy to be damaged, so when designing a pressure sensor circuit for an automobile, it is necessary to choose a chip with overvoltage protection

However, because the current automotive pressure sensor market is mainly monopolized by BOSCH (Bosch), Sensata (Sensata), Denso (Nippon Denso) and other companies, it is not easy to buy, and third-party manufacturers have insufficient design process capabilities or market research capabilities. The problem is that the designed ASIC (Application Specific Integrated Circuit) chip does not have an overvoltage or negative pressure protection circuit. Therefore, because the automotive pressure sensor lacks the necessary overvoltage protection function, the failure rate of the automotive pressure sensor a substantial increase in

Images