Semiconductor Components Industries, LLC

Sanyo Electric Co., Ltd.

Sanyo Semiconductor Co., Ltd.

Yoshio Fujimura

Hiroshi Iizuka

Shuhei Kawai

Kazunari Kushiyama

Koudai Nakamura

Yuusuke Nishizaki

Kenpei En

Yasunari Noguchi

Satoru Yoshioka

Yusuke Nishizaki

A control circuit of a light-emitting element comprises a rectifying unit which full-wave rectifies an alternating current power supply, a clock generator which generates and outputs a clock signal (CLK), a first comparator which compares a comparison voltage (CS) corresponding to a current flowing to the light-emitting element and a reference voltage (REF), and a switching element which is set to an ON state in synchronization with the clock signal (CLK) and which is set to an OFF state when the comparison voltage (CS) becomes greater than the reference voltage (REF) at the first comparator, to switch the current flowing to the light-emitting element. In this structure, a period of the clock signal (CLK) generated in the clock generator is varied, to reduce or inhibit noise.

Control circuit of light emitting element

A driver circuit is provided which comprises a series-connected unit having a light-emitting element and a current limiting inductor directly connected to the light-emitting element, a regenerative diode which is connected in parallel to the series-connected unit and which regenerates energy stored in the current limiting inductor, a transistor which controls a current flowing through the light-emitting element and the current limiting inductor, and a controller which controls an operation of the transistor, wherein the controller controls the transistor according to a voltage value of a power supply applied to the light-emitting element.

Method for driving a light-emitting unit and circuit therefor

Control circuit of light-emitting element

Driver circuit of light-emitting element

A control circuit comprises a rectifier unit for performing full wave rectification on an AC power source, a switching element for switching a current flowing through a light emitting device which emits light in response to a voltage having been full wave rectified in the rectifier unit, a voltage dividing circuit for dividing the voltage having been full wave rectified in the rectifier unit to obtain a reference voltage Vref, a comparator for comparing a comparison voltage Vcmp corresponding to the current flowing through the light emitting device with the reference voltage Vref, and a control unit for controlling switching of the switching element based on a comparison result obtained in the comparator.

Control circuit for light emitting device

A quasi resonant type switching power supplying unit includes an overcurrent limiting circuit and an oscillation level comparison circuit. The overcurrent limiting circuit (i.e., a level determining circuit and a reference voltage generating circuit) receives a reverse electromotive voltage generated from an auxiliary winding which is electromagnetically connected with a primary winding when a MOSFET is in an OFF state, and produces a reference voltage stepwise based on the reverse electromotive voltage. The oscillation level comparison circuit receives a feedback voltage corresponding to electric power supplied to a load, and produces a control signal that switches the MOSFET into an OFF state when the feedback voltage exceeds the reference voltage.

Quasi resonant type switching power supply apparatus with overcurrent limiting

Growing community of inventors

Ota, Japan

Yoshio Fujimura