CIRCUITS AND METHODS FOR CONTROLLING CURRENT IN A LIGHT EMITTING DIODE ARRAY

摘要

In one embodiment, a circuit comprises a current source to produce current to a light emitting diode array. An analog dimming circuit generates a continuous control signal to the current source to control the current in the light emitting diode array according to a range of control signal values when the control signal is above a threshold. Below the threshold, a digital modulation circuit generates an additional modulated digital signal to the current source to control the current in the light emitting diode array according to a range of modulation values when the continuous control signal is below the threshold. The continuous control signal produces current from the current source into the light emitting diode array above a first value. The combination of the continuous control signal and the modulated digital signal produces current in the light emitting diode array below the first value.

主权项

1. A circuit comprising:
a current source to produce current to a light emitting diode array; an analog dimming circuit to generate a continuous control signal to the current source to control the current in the light emitting diode array according to a range of control signal values when an input signal is above a threshold and to generate the continuous control signal according to a control signal value when the input signal is below the threshold; and a digital modulation circuit to generate a modulated digital signal to the current source to control the current in the light emitting diode array according to a range of modulation values when the continuous control signal is below the threshold; wherein the continuous control signal produces current from the current source into the light emitting diode array above a first value, and the modulated digital signal in combination with the continuous control signal produces current from the current source into the light emitting diode array below the first value.