PWM waveform

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1

Hi.

For instance i have a two PWM waveforms.

The period in first case is, let’s say 1 milisec, with a duty cycle 50%.

In second case the period is 1 microsec, with 50% duty cycle.

The period in the second case is 1000 times less than in the first case, so the resoluiton is much better.

Is better to generate PWM waveforms with a small period?

Why is a better resolution ?

2

I dont know what background knowledge you have on the topic, but higher resolution is always desirable and the specific advantages of higher resolution depend on the application itself.

But in your case increase in the frequency (and the reduction in the time period) doesnot necessarily mean that your resolution has increased. Resolution determines the smallest possible change that you can make to the duty cycle and not the period itself.

3

LadyInRed:
The period in the second case is 1000 times less than in the first case, so the resoluiton is much better.

The only conclusion you can draw from this is that the frequency of the second waveform is 1000 times higher than that of the first.

Is better to generate PWM waveforms with a small period?

Why is a better resolution ?

There is no single answer to this since it depends on the application. In power conversion applications, your PWM period it tightly bound to the characteristics of the magnetics in your design. In a simple resistive LED dimmer where you want to avoid the strobing effect of the light, after a certain point, increasing the frequency will give you diminishing returns at the expense of increasing switching losses in your transistors.

It’s all a balancing act where values can range from completely arbitrary to 100% critical depending on the application.

-Bill