IRS20955 Help!

[Himlam8484]

Hi people,

I made a class D amplifier circuit with a IC driver IRS20955 and
Mostfets for output. I test it, but it seem to be wrong. When I input
PWM signal (50% duty cycle), The output signal's waveform is nearly
sine wave. Is it right???? An Class D amplifier with PWM(50% duty
cycle) is output signal should be a DC waveform.

Can anyone clarify for me?

Him Lam

 

[Phil Allison]

"Himlam8484"

I made a class D amplifier circuit with a IC driver IRS20955 and
Mostfets for output. I test it, but it seem to be wrong. When I input
PWM signal (50% duty cycle), The output signal's waveform is nearly
sine wave. Is it right???? An Class D amplifier with PWM(50% duty
cycle) is output signal should be a DC waveform.

Can anyone clarify for me?

** Go figure what the output filter does:

http://www.irf.com/technical-info/appnotes/an-1071.pdf


Note that the average value of a sine wave is zero.



........ Phil

 

[Himlam8484]

"Himlam8484"





** Go figure what the output filter does:

http://www.irf.com/technical-info/appnotes/an-1071.pdf

Note that the average value of a sine wave is zero.

....... Phil

Thanks for reply, i will check it now!

Him Lam

 

[Jamie]

Hi people,

I made a class D amplifier circuit with a IC driver IRS20955 and
Mostfets for output. I test it, but it seem to be wrong. When I input
PWM signal (50% duty cycle), The output signal's waveform is nearly
sine wave. Is it right???? An Class D amplifier with PWM(50% duty
cycle) is output signal should be a DC waveform.

Can anyone clarify for me?

Him Lam

I think you have some misconceptions of a class D amplifier.