Elite Semiconductor Microelectronics Technology Inc.

Oriental System Technology Inc.

Yi-Chou Huang

Po-Tzu Chen

Yu-Te Chen

Teng-Wen Chang

A capacitance measurement circuit includes a charge to voltage converter (CVC) that includes at least one first variable capacitor, an excitation signal generation circuit, a differential amplifier, a first switch circuit, and at least one second variable capacitor, wherein a parasitic capacitance from a sensing capacitance sensed by a capacitance sensor is reduced by the at least one first variable capacitor. The excitation signal generation circuit is arranged to generate and connect a first excitation signal to the capacitance sensor, and generate and connect a second excitation signal to the at least one first variable capacitor, wherein the first excitation signal and the second excitation signal are out-of-phase, and a voltage amplitude of the first excitation signal is different from a voltage amplitude of the second excitation signal. The inverting input terminal of the differential amplifier is arranged to receive the sensing capacitance from the capacitance sensor.

Capacitance measurement circuit

A capacitance measure circuit includes a charge to voltage converter (CVC), and the CVC includes an excitation signal generation circuit that is arranged to generate and connect an excitation signal to a first terminal of a capacitance sensor, a differential amplifier, a first switch circuit, and at least one first variable capacitor. The inverting input terminal of the differential amplifier is arranged to receive a sensing capacitance value from a second terminal of the capacitance sensor. The first switch circuit is coupled between the inverting input terminal and the non-inverting output terminal of the differential amplifier, and is connected in parallel with the at least one first variable capacitor at the inverting input terminal and the non-inverting output terminal of the differential amplifier.

A hair dryer comprises a fan, a heater, a temperature sensor, and a controller. The heater is disposed at the airflow output end of the fan and used to heat the airflow output by the fan. The temperature sensor is pointed to the hair, receiving the infrared light radiated by the hair to obtain the temperature of the hair, determining the dryness of the hair according to at least one of the temperature of the hair and the rate of temperature variation of the hair, and outputting a corresponding control signal. The controller is electrically connected with the fan, the heater and the temperature sensor, and controlling at least one of the rotation speed of the fan and the heating power of the heater according to the control signal. The above-mentioned hair dryer not only can prevent from hair overheating and hair damage but also can shorten the time for drying hair.

Growing community of inventors

Hsinchu, Taiwan

Yi-Chou Huang