LIGHT EMITTING DEVICE DRIVER CIRCUIT

摘要

The present invention discloses a light emitting device driver circuit. The light emitting device driver circuit drives a light emitting device circuit. The light emitting device circuit includes plural light emitting devices connected in series and a diode circuit, wherein the plural light emitting devices are divided to plural groups. The light emitting device driver circuit includes: a first switch circuit, a second switch circuit, a current source circuit, and a control circuit. The first switch circuit includes plural first switches connected in parallel to the corresponding groups respectively. The second switch circuit includes plural second switches coupled to a forward end and a reverse end of the diode circuit respectively, wherein the second switch circuit determines whether to conduct the forward end or the reverse end to the current source circuit according to the voltages of the forward end and the reverse end.

主权项

1. A light emitting device driver circuit for driving a light emitting device circuit which is operative according to a rectified input voltage, the light emitting device circuit including a plurality of light emitting devices connected in series and a diode circuit, wherein the diode circuit includes at least one diode or a light emitting diode (LED), and wherein the light emitting device circuit and the diode circuit are connected in series, the plural light emitting devices being divided into a plurality of groups, wherein each group includes at least one light emitting device, the light emitting device driver circuit comprising:
a first switch circuit, which includes a plurality of first switches, wherein each first switch is connected to a corresponding one of the groups in parallel; a second switch circuit, which includes a plurality of second switches, wherein each forward end and each reverse end of each diode or LED in the diode circuit is coupled to a corresponding one of the second switches; a current source circuit, which is coupled to the second switch circuit, for providing a light emitting device current when at least one of the light emitting devices is conductive, wherein the second switch circuit determines whether to electrically connect the forward end or the reverse end of the at least one diode or LED in the diode circuit to the current source circuit according to voltages of the forward end and the reverse end; and a control circuit, which is coupled to the first switch circuit, for generating an operation signal according to an adjustment signal, to operate at least one first switch of the first switch circuit to determine which of the light emitting devices is conductive.