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Re: Oscillator circuit for solid-state TC
Greetings
> Duane Bylund in his book has
> a circuit built around the "SG3524" IC which has a maximum operating
> frequency of 150 khz.
Yes I've used the 3524 chip - I'm sure I pushed it to 200kHz.
The big advantage of these chips is that they are designed
to provide all the control for a switching power supply.
Controling the frequency and the pulse width, and giving
soft start and a means of limiting the current - dual outputs
with identical pulse widths for driving a bridge or a push pull.
I moved to the 3825 chip - it can go up
to 500kHz and the outputs can drive MOSFET's directly.
(these chips are made by more than one manufacturer -
SG3524=LM3524=UC3524=CA3524 -
get everybody's data sheets - lots of circuit ideas)
I'm going back to the CA3524 to replace the 555 as the low
frequency switch. Running continuosly draws serious power
so I switch the oscillator on/off at about 60Hz with a varying
on/off ratio - more spark- less smoke :)
Get the data sheet for the Harris version - the CA1524/3524
It includes, figure 22, low frequency pulse generator. Frequency
with values shown is 75-250Hz, 0-45% duty cycle. I'll go to
40- 250 Hz by changing the timing components.
(Harris Semiconductors are on the net - data sheets and viewer
are down loadable)
Now that I'm working at 100kHz I may go back to the 3524 for
that side too.
Have fun,
Alan Sharp (UK).