Circuit for operating series of LEDs used in backlight of e.g. LCD TV, has one transistor with gate and source electrically coupled to ground, and drain connected with series of LEDs

摘要

The circuit (10) has a transistor (M1) such as metal oxide semiconductor (MOS) transistor having a gate and source coupled to ground through a resistor (R2), and a drain connected to a circuit for providing a voltage of predetermined value. A transistor (M2) has a gate and a source electrically coupled to ground, and a drain connected with the series of LEDs. A resistor (R4) has one end electrically coupled to the gates of the transistors. A current source (14) is electrically coupled between the end of the resistor (R4) and the drain of the transistor (M1).