Multiple Stage Sequential Current Regulator

摘要

An LED driver circuit for controlling direct current supplied to a plurality of serially connected segments of Light Emitting Diodes (LEDs) is disclosed. In one embodiment, the LED driver circuit comprises a self-commutating circuit, which comprises a plurality of current control elements, each current control element having two ends, a first end connected to a different end of each segment along the plurality of serially connected segments of LEDs and a second end connected to a path to ground. The path to ground comprises a sense resistor and the path to ground is shared by the second end of each current control element. Each current control element is coupled to an adjacent current control element by a cross-regulation circuit and controlled by a signal from an adjacent current control element.

主权项

1. An LED driver circuit for controlling direct current supplied to a plurality of serially connected segments of Light Emitting Diodes (LEDs) from a source of rectified alternating current voltage, said circuit comprising:
a self-commutating circuit comprising a plurality of current control elements, each current control element having two ends, a first end connected to a junction between adjacent segments of LEDs along the plurality of serially connected LEDs and a second end connected to a shared path to ground, wherein the shared path to ground comprises a common point where the currents from multiple current control elements flow allowing single-point control over total current drawn from the source of rectified alternating voltage; each current control element being coupled to an adjacent current control element by a cross-regulation circuit and controlled by a signal from an adjacent current control element; wherein a first cross-regulation circuit modulates current in a current control element in response to a signal from a second cross-regulation circuit; wherein the second cross-regulation circuit produces a signal in response to current flowing thru an adjacent current control element.