conal
Newbie level 3
spread spectrum for pwm
I am desiging a spread spectrum dc-dc converter with a +-3% spread around a programmable centre frequency of 500K to 2.4MHz. I am planning to change the frequency every cycle using a pseudo-random bit sequence generator.
My question is, what should the cycle repition time of the pseudo-random generator be? If the cycle repitition time is in the audio range 20Hz to 20KHz, will I get a buzzing sound from dc-dc due to inductor magnetostriction? I am finding that if I want to keep my cycle repition time below the audio range I will have to use a very long and area inefficient shift register - hence the question.
Your help is much appreciated.
Cheers
conal
I am desiging a spread spectrum dc-dc converter with a +-3% spread around a programmable centre frequency of 500K to 2.4MHz. I am planning to change the frequency every cycle using a pseudo-random bit sequence generator.
My question is, what should the cycle repition time of the pseudo-random generator be? If the cycle repitition time is in the audio range 20Hz to 20KHz, will I get a buzzing sound from dc-dc due to inductor magnetostriction? I am finding that if I want to keep my cycle repition time below the audio range I will have to use a very long and area inefficient shift register - hence the question.
Your help is much appreciated.
Cheers
conal