Time delay compensation and pulse width correction

Abstract

A system, method and apparatus is provided for pulse width correction in a power driver. In an embodiment, an apparatus includes an operational amplifier having an input and an output. The input of the operational amplifier is coupled to receive an input pulse signal. The apparatus further includes an output stage having an input coupled to the output of the operational amplifier. The output stage also includes a current output configured to couple to a load and to a voltage sense output. The apparatus also includes a comparator having an inverting input coupled to the voltage sense output of the output stage, a non-inverting input configured to couple to an input signal, and an output. Also, the apparatus includes a timing circuit with an input coupled to the output of the comparator and an input coupled to the input signal. The timing circuit also has an output to supply the input pulse signal. The timing circuit measures a delay from a change in the input signal to a change in the output of the comparator. The timing circuit replicates the measured delay as a delay in a change to the input pulse signal.

Description

Background technique [0001] Replicating pulse width becomes important when operating dimmers or other pulse width dependent circuits. This can lead to significant problems if the pulse width at the input differs significantly from the pulse width at the corresponding output. For example, a pulse may not get an output signal due to slew speed limitations that may prevent the output stage from turning on. Likewise, due to changes in the width of the pulses provided to the output, the desired effect of certain pulse widths may be limited or not achieved at all. [0002] Many applications use pulsed power waveforms to power components. For example, light emitting diodes (LEDs) can be driven with a pulse waveform. Likewise, an audio device such as a subwoofer can be powered by a pulse waveform drive. Additionally, dimmer switching is often implemented with a pulsed waveform as the power output to the component being dimmed or controlled. [0003] Therefore, it is useful to fin...

AI Technical Summary

Problems solved by technology

This can cause significant problems if the pulse width at the input is significantly different from the pulse width at the corresponding output

For example, a pulse may not get an output signal due to slew speed limitations that may prevent the output stage from turning on

Also, due to changes in the width of the pulses presented to the output, the desired effect of a certain pulse width may be limited or not achieved at all

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