Low cost LED driver with integral dimming capability

摘要

A distributed system for driving strings of series-connected LEDs for backlighting, display and lighting applications that includes multiple intelligent satellite LED driver ICs connected to an interface IC via a serial lighting interface bus. The interface IC translates information obtained from a host microcontroller into instructions for the satellite LED driver ICs pertaining to such parameters as duty factor, current levels, phase delay and fault settings. Fault conditions in the LED driver ICs can be transmitted back to the interface IC. An analog current sense feedback system which also links the LED driver ICs determines the supply voltage for the LED strings.

主权项

1. A light emitting diode (LED) driver integrated circuit (IC) comprising:
a transistor having a gate terminal, a source terminal, and a drain terminal, the drain terminal constructed to couple to at least one LED string; a reference current source constructed to generate a reference current; a first register to store data representative of a desired magnitude of current in the at least one LED string; and a driver circuit having an output coupled to the gate terminal of the transistor, a first input coupled to the source terminal of the transistor, a second input coupled to the reference current source to receive the reference current, and a third input coupled to the first register to receive the data representative of the desired magnitude of current in the at least one LED string, the driver circuit constructed to control an amount of current in the at least one LED string based on the reference current and the desired magnitude of current in the at least one LED string.