An idea to improve the PSU.
Could it be made dual channel meaning a negative and positive rails, I have seen DBS(digital Bench top supplies) available here in my city which have negative and positive rails and supply is adjusted via pots one for positive rail and other for negative rail.
Such a supply gives a good way of testing OP-AMPS and other applications requiring dual rail of supply.
I have simulated the "PWM" sections both the elektor and this one.... the 16F84 puts out a series of pulses(about 1% ON 99%OFF duty cycle) and is alternating for bothe PWM1 and PWM2 outputs..... the 16F876, I find akward? the PWMs are "adjusted" through the ON duty cycle %....BOTH of the outputs do this... and I wonder HOW he manages to control the voltage/current with it... esp when you diode "OR" them....
I will post images to make it much clearer
the problem with the elektor is when you power down, and back again, all controls reset to ZERO... at least thats what my simulator show(proteus)
on the elektor ckt though, I STILL dont get it, how it "READS" the current/voltage... is the TLC272, oscillating?? or just plain comparator?? I wonder if this can be replaced with LM358...16F84 has no analog input...