The utility model discloses a motor over-temperature protection circuit for an
electric power steering system, and relates to the field of
electric power steering systems. The bridge module is composed of a temperature detection
resistor and a plurality of resistors with fixed resistance values; the temperature detection
resistor is used for detecting the temperature of the motor; the bridge module is used for converting the resistance change of the temperature detection
resistor into
voltage change and forming a differential
signal; the design of the bridge module improves the sensitivity of temperature detection, and as the resistance value of the temperature detection resistor changes along with the change of the temperature, the change of the temperature can be accurately sensed by monitoring the output
voltage of the bridge module, especially under the condition of small
temperature difference; in addition, two-stage amplification is achieved through the first-stage amplification module and the second-stage amplification module, signals are enhanced, meanwhile, due to the fact that each stage of
amplifier works in the linear working area of the
amplifier, the saturation problem possibly encountered by a single high-
gain amplifier is avoided, and
nonlinear distortion is reduced.