SELECTION OF CROSS OVER FREQUENCY IN SMPS

sudeep e

Intellectual 525 points

HOW TO SELECT THE CROSSOVER FREQUENCY WHILE DESIGNING SMPS..

WHETHER WE HAVE TO CHOOSE GREATER THAN SWITCHING FREQUENCY OR LESS THAN THAT.

IF THE SWITCHING FREQUENCY IS 150KhZ

over 9 years ago

0 JohnTucker over 9 years ago

TI__Guru**** 191445 points

You absolutely cannot go above Fsw/2. General rule of thumb is to place Fco at 1/10 to 1/5 of Fsw. So for Fsw = 150 kHz, Fco = 15 to 30 kHz. It will depend on your output filter also. You want to ensure the gain slope is -20 dB / decade at crossover.

0 Helen chen over 9 years ago

TI__Mastermind 40080 points

For the buck converter, it can be 1/10 to 1/5 of Fsw.
For the boost converter, please take the right half plane zero fz_rhp into account. the crossover frequency should be <1/10 fsw and <1/5 fZ_rhp

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SELECTION OF CROSS OVER FREQUENCY IN SMPS