Analog Devices, Inc.
Single comparator exponential-scale PWM dimming

Abstract:

An exponential scale pulse width modulation (PWM) controller comprises a waveform generator circuit configured to generate a logarithmic waveform signal that has the shape of an increasing logarithm function; and a first comparator circuit including a first input to receive the logarithmic waveform signal, a second input to receive an input signal, and an output that provides a PWM control signal that includes signal pulses having a duty cycle that changes exponentially with respect to the input signal.