On Sun, Nov 15, 2009 at 5:32 PM, M.L. wrote: > On Sun, Nov 15, 2009 at 9:02 AM, Marcel Birthelmer > wrote: >>> A proven option would be a PIC-controlled SMPS. The PIC16F616 has an >>> enhanced PWM module which would work nicely for a buck-boost. It has >>> hardware-triggered PWM output shutdown and restart as well. It's a >>> pretty inexpensive part. >>> >> >> Do you have any documents/design guidelines/example projects for this? >> I've seen the Microchip App Note for the SMPS buck regulator, but I'd >> like to see some more information about how to apply control theory >> principles to generate a particular output voltage. >> Thanks, >> - Marcel > > You could read a digital control systems book and apply that to what > you desire. It's not necessary, but I'm not going to tell you it's a > bad idea. I know of a few names on this list who have used PICs in > real, working, SMPS designs without doing complex analysis. I did read Olin's paper about the PFC (which conceptually isn't really different), and I have some background in DSP/Control Theory stuff. I'm just wondering about how good (in terms of overshoot, stability, etc.) a controller can be made without really having a solid model of the converter topology. I mean, sure, you could just have a simple feedback system in terms of the current or output voltage and generate the switch voltage from that, but there seem to be many gray areas that would be unexplained (for example: what sort of parameters are appropriate for a PID controller in this case? Are there any unstable regions when switching from constant-current to constant-voltage output (such as might be the case for a battery charger, for instance)?). I'm just trying to get a more theoretical understanding of how to come up with a model for such a converter. Regards, - Marcel -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist