I'm starting a project to do a DC/DC boost from a solar panel. I want to make small panels, ~16 watts, with the .5V, 4A cells you can get for cheap on eBay. So my voltage out of the panel will be around 3.7v ~ 4.5V. I plan to run this through a filter cap and power my PIC and logic.
I plan to use the PWM on the PIC to boost the voltage so that I can use the panel to drive motors, charge batteries, etc. I know there are DC/DC boost IC's but I've already need the PIC for other functions and I want to learn the ins and outs of voltage conversion. I need to be able to vary the output voltage from about 10V to 18V depending on the load and available current coming from the panel. So current would vary from around .8A to 1.6A.
I've done a bunch of reading about boost converters, inductors and magnetic fields. So the basic circuit will look like this:
Where I'm confused is where to start as far as what specs I need for the inductor and what PWM frequency to start at. Do I vary the duty cycle on the PWM or just the frequency? How do I spec the diode and cap too?
It seems if I use a higher frequency I can use a smaller inductor?
If anyone can point me at some information so I can learn what values are necessary for the voltages and currents I'd really appeciate it. Thanks!
I plan to use the PWM on the PIC to boost the voltage so that I can use the panel to drive motors, charge batteries, etc. I know there are DC/DC boost IC's but I've already need the PIC for other functions and I want to learn the ins and outs of voltage conversion. I need to be able to vary the output voltage from about 10V to 18V depending on the load and available current coming from the panel. So current would vary from around .8A to 1.6A.
I've done a bunch of reading about boost converters, inductors and magnetic fields. So the basic circuit will look like this:
Where I'm confused is where to start as far as what specs I need for the inductor and what PWM frequency to start at. Do I vary the duty cycle on the PWM or just the frequency? How do I spec the diode and cap too?
It seems if I use a higher frequency I can use a smaller inductor?
If anyone can point me at some information so I can learn what values are necessary for the voltages and currents I'd really appeciate it. Thanks!