DIMMING CIRCUIT WITH REFERENCE CONTROL

    公开(公告)号:US20210144817A1

    公开(公告)日:2021-05-13

    申请号:US16861282

    申请日:2020-04-29

    IPC分类号: H05B45/10 H05B45/46 H05B45/35

    摘要: A balance circuit includes a reference circuit configured to generate current through strings of light emitting diodes (LEDs). The reference circuit includes a first string of LEDs in series coupled to a collector node of a first transistor. A base drive current resistor is connected between the collector node and a base node of the first transistor. A base emitter resistor is connected between the base node and an emitter of the first transistor such that a reference voltage is generated on the base node during operation. Another stage receives the reference voltage to generate a tracking current through a second transistor and a second string of LEDs connected to a base of the second transistor, wherein a current through the first string of LEDs is uniformly tracked by the tracking current through the second string or LEDs.