output frquncy of UC3845

[mail2vasu2004]

HI all,

I am using current controller PWM IC UC 3845, i am confused about it output frequency and oscillating frequency. Is it true that the output frequency for this IC is half of oscillating frequency.

Is this also applicable to other PWM Ics.

vasu

 

[RJM1]

No. See data-sheet.

http://focus.ti.com/lit/ds/symlink/uc3845.pdf

 

[RJM1]

Oops, I was wrong. The UC3842,43 has the same oscillating frequency as output frequency and have a maximum duty cycle approaching 100%. The UC3844,45 blank the output every other clock cycle and the output frequency is 1/2 of the oscillating frequency with a max duty cycle of 50%.

I usually use the UC3842.

 

[mail2vasu2004]

Oops, I was wrong. The UC3842,43 has the same oscillating frequency as output frequency and have a maximum duty cycle approaching 100%. The UC3844,45 blank the output every other clock cycle and the output frequency is 1/2 of the oscillating frequency with a max duty cycle of 50%.

I usually use the UC3842.

Thank you

even the example in the datasheet states the same

vasu