Seoul Semiconductor Co., Ltd.

Byung Hoon Choi

In Kyu Park

Do Hyung Kim

The disclosure relates to an AC LED dimmer and dimming method thereof. The AC LED dimmer includes a rectifier receiving AC voltage from an AC voltage source and full-wave rectifying the AC voltage; a direct current (DC)/DC converter receiving the full-wave rectified voltage from the rectifier, generating a full-wave rectified stepped-up voltage, and generating a pulse enable signal; a pulse width modulation controller receiving the full-wave rectified stepped-up voltage and generating a pulse width modulation signal to dim an AC LED in response to the pulse enable signal; a switch driving the AC LED under control of the pulse width modulation signal, and an electromagnetic interference (EMI) filter to be connected between the AC voltage source and the switch to eliminate electromagnetic interference from the AC voltage source. Accordingly, the dimmer can perform an efficient and linear dimming function and suppress harmonics.

AC LED dimmer and dimming method thereby

An AC light emitting device, a driving device thereof and a driving method are disclosed. The driving device includes a sub-driving part turned on corresponding to each of positive and negative voltage regions of an AC voltage source to provide current paths for operating at least two LEDs, and a free-charge part charging with a voltage to be supplied to one of the at least two LEDs which is not operated while the other LED is operated by the sub-driving part. The AC light emitting device, the driving device thereof and the driving method thereby can solve problems, such as a decrease in power factor, severe total harmonic distortion, excessive flickering, and the like, due to operating characteristics of the AC light emitting device by application of an AC voltage source thereto.

Growing community of inventors

Ansan-si, South Korea

Byung Hoon Choi