Murata Manufacturing Co., Ltd.

Yoshinori Kitamura

Hiroki Tanaka

Hiromasa Ito

An LED drive circuit that sufficiently exhibits the performance of an LED element to obtain a favorable luminance at room temperature, includes a constant-current circuit including an LED element, a constant-current output unit, and a temperature sensing element having a negative resistance-temperature coefficient. The LED element is connected to the constant-current output unit in series. The constant-current output unit is connected to the LED element in parallel. Due to changes in the resistance value of the constant-current output unit caused by changes in temperature, the value of a current passing through the LED element is increased at room temperature and the value of a current passing through the temperature sensing element is reduced at high temperature.

LED drive circuit

An inexpensive positive temperature coefficient thermistor has metal terminals which have been miniaturized without deteriorating the characteristics or sacrificing the reliability of the device. The metal terminals include supporting members and springs constructed such that a total width of the supporting members is smaller than a total width of the springs. In addition, connecting portions at the upper ends of the metal terminals engage with a case main body or a covering member to be retained at predetermined positions.

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Konan, Japan

Yoshinori Kitamura