LED lighting driver

摘要

A light-emitting diode (LED) lighting driver is provided, which includes a bridge rectifier, multiple LED sections, multiple shunt regulators, a weighted current mirror array, a mean power integrator, and a reference generator. The bridge rectifier provides a rectified sinusoidal voltage. The LED sections are coupled in series and coupled to the rectified sinusoidal voltage. Each shunt regulators regulates a shunt current flowing out from the LED sections according to a current reference value. The weighted current mirror array provides a plurality of copy currents. Each copy currents tracks the conduction time of one shunt regulator and also tracks the instantaneous output power of the LED sections. The mean power integrator provides a mean power value by integrating the copy currents. The reference generator provides the current reference values. Each current reference values is directly proportional to the difference between a mean power reference value and the mean power value.

主权项

1. A light-emitting diode (LED) lighting driver, comprising:
a bridge rectifier, providing a rectified sinusoidal voltage by receiving and rectifying a utility alternating current (AC) voltage; a plurality of LED sections coupled in series, wherein the first LED section is coupled to the rectified sinusoidal voltage; a plurality of shunt regulators coupled to the LED sections, wherein each of the shunt regulators regulates a shunt current according to a current reference value, each of the shunt currents flows from a terminal of one of the LED sections to a ground; a weighted current mirror array coupled to the shunt regulators and providing a plurality of copy currents, wherein each of the copy currents tracks a conduction time of one of the shunt regulators and also tracks an instantaneous output power of the LED sections; a mean power integrator, coupled to the weighted current mirror array, providing a mean power value by integrating the copy currents; and a reference generator, coupled to the mean power integrator and the shunt regulators, providing the current reference values to the shunt regulators, wherein each of the current reference values is directly proportional to a difference between a mean power reference value and the mean power value, wherein the weighted current mirror array comprises: a primary current mirror, coupled to the reference generator, regulating a primary current according to one of the current reference values; and a plurality of secondary branches, wherein each of the secondary branch comprises: a current-generating transistor, coupled to the primary current mirror, generating one of the copy currents, wherein the one copy current is equal to an arithmetic product of the primary current and a weighted factor; and a current switch, coupled to the current-generating transistor, one of the shunt regulators, and the mean power integrator, providing the one copy current to the mean power integrator when turned on by an output signal of the one shunt regulator.