Project: step-up converter

I have decided to add various projects using Tinyboard directly
to this repository. The first project is a step-up converter
with current feedback for a string of LEDs.

The firmware is a dumbed-down version of firmware for my other
project: http://www.fi.muni.cz/~kas/bike-lights/, modified
for ATtiny45.

projects/step-up/README

+Step-up converter with current feedback measurement.
+
+CPU: ATtiny45
+Driven by PWM output OC1B (PB4 pin) with MOSFET.
+Current feedback measured at ADC3 (PB3 pin).
+Output on the PB4 header (pin 1 is negative, pin 2 is positive side).
+
+
+Bill of materials:
+
+C1,C2	1.5uF tantalum
+C3,C51	10uF ceramic
+D50	SS24 Schottky diode (SMB package, 40V, 2A)
+L50	470uH, 390mA, 200 mil pin distance (probably too big for 20mA LEDs :-)
+PB4	two-pin header soldered to pins 1 and 2 of PB4
+Q50	IRLML6344TRPBF N-channel MOSFET, 30V, 5A, SOT-23 package
+R40	220nF capacitor (not resistor!)
+R45	1K5
+R50	15K
+R51,R53	0R00 (zero-ohm link)
+R55	1R0 (can safely measure currents from ~8 mA up, for smaller currents use higher value)
+U1	ATtiny45-20SU
+U2	MCP1703T-5V
+
+
+Firmware:
+
+The firmware is a dumbed-down version of firmware for my other
+project: http://www.fi.muni.cz/~kas/bike-lights/, modified
+for ATtiny45.
+