Integrated Device Technology, Inc.

Tyco Electronics (shanghai) Co., Ltd.

Ye Sun

Xinhui Mao

Jiang Li Xin

Jianwu Zhou

Jiacheng Zhou

The invention provides a sensing circuit having a driving apparatus, that is, a current drive circuit and a voltage drive circuit. The current drive circuit drives a sensor in a current drive mode, and the voltage drive circuit drives the sensor in a voltage drive mode. The sensing circuit further has a switch apparatus connected to the driving apparatus for controlling the driving apparatus, to enable the driving apparatus to switch between the current drive mode and the voltage drive mode. A temperature testing circuit with a negative temperature coefficient thermistor is further used to sense ambient temperature of the sensor, and the input voltage of the switch apparatus is changed by means of that the resistance of the thermistor changes as the temperature changes, so as to control on and off of the switch apparatus, to switch the drive mode of the sensor.

Sensing circuit, hybrid drive circuit, and sensor assembly

Consistent with the present invention, there is provided a circuit for extracting a common mode voltage of an input signal. The device may include an operational amplifier having an output, at least one negative input and at least one positive input, a first transistor, and a second transistor. A terminal of the first transistor may be coupled to the output of the operational amplifier. A terminal of the second transistor may be coupled to a terminal of the first transistor and the at least one positive input of the operational amplifier to create a negative feedback loop. The device may further include a common mode output, wherein the negative feedback loop extracts the common mode voltage of the input signal, the common mode voltage of the input signal being output at the common mode output. The device consistent with the present invention may provide the common mode voltage of the input signal without using any resistors, and while only occupying a small die area.

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Shanghai, China

Ye Sun