Tdk Corporation

Yukiharu Miyaoka

Kazunori Oshima

Hironobu Masuoka

Mitsuyuki Tsujisaka

A light emitting element drive device with PWM dimming includes an LED module, a power conversion circuit that supplies electric power to the LED module, a dimming switch element that performs an open/close operation for a path in which a current flows in the LED module, and a voltage detection circuit that detects a voltage value of a voltage that is output from the power conversion circuit. When the dimming switch element is turned ON, a control circuit performs feedback control so as to make a current value of the current close to a first target value. When the dimming switch element is turned OFF, the control circuit performs feedback control so as to make the voltage value close to a second target value. Wherein, the first target value is a predetermined value and the second target value is set based on the voltage value.

Light emitting element drive device

A light emitting element drive device includes an electric conduction switch that is provided along a power input line, a voltage detection unit that detects a power source voltage containing a noise component when the electric power is supplied to the power input line, a conversion processing unit that converts the detected power source voltage containing the noise component to a digital value, a data generation unit that generates data of a predetermined number of bits, and a control unit that turns on the electric conduction switch. The control unit determines a delay time based on the predetermined number of bits. The delay time corresponds to a time between supplying the electric power to the power input line and turning on the electric conduction switch. The control unit turns on the electric conduction switch after the delay time passes. Thus, an excessive rush current is prevented.

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Tokyo, Japan

Yukiharu Miyaoka