Universal PIC switchmode status report
Today got all functions working, but have not connected a shunt to measure output current yet (in case one wanted to know the exact value).
Here is a picture of the power_PIC with the LCD attached, and a RS232 request for 6.0V: ftp://panteltje.com/pub/power_pic/power_pic_working_img_0905.jpg
The LCD reads topline: time, voltage setpoint, and current limit value.
The bottom line reads: Output Watts, output voltage, output current.
(The clock can be used for software battery charger routines later).
Watts is zero as no current sense connected, and is simply Uout x Iout.
I have to interrupt this project now because my RGB LED strips arrived, here a picture of one: ftp://panteltje.com/pub/col_pic/RGB_LED_strip_img0906.jpg
Much brighter then I expected!
170 mA @ 12V for one such a strip, green 70 mA, red 60 mA, and blue 40 mA.
Back to powerPIC: In theory I will need an opamp to amplify the voltage across a big shunt a bit, but in practice maybe if I let the internal ADC use the PIC's internal 0.6 V reference, and as it has a 10 bit ADC with 1024 steps, that would give .5 mV resolution, or, with a 20 mOhm shunt, 25 mA resolution..... For a 10 A full scale that would suffice for this LCD. Cool, have to see if that all works, and if I can select .6 V reference for the ADC while selecting other references for other things like the comparators.