LED driver for single lipo/lion cell with step up (5-28V, 1A) constant current (0.6A, 225mW dissipation) regulator, TP4056 charger (20-1000mA), over-/undervoltage protection (2.5V-4.3V) and a microcontroller.
The circuit output is 7-9.2V (R6+R11/R7) for 3 high power LEDs in series, constant current 30-35mA (R8). P9 needs to be connected to B+ (on) or GND (off). It can also be used to dim the LEDs...
![LED driver 1A 2.png](//image.easyeda.com/pullimage/pyW3A5ZZfFKeFs0urNFYrR6nrWxFsTLqp6fUsyyn.png)
**Until furter notice: This is a work in progress**
***This circuit DOES NOT WORK with the currently suplied BOM! ***
*30.04-2019 All parts have finaly arrived and i've finished two LED driver sircuits. Solderjob have been veryfied with magnifying lens and multimeter.
Results are pretty much the...
Discharge up to eight 1.5V alkaline cells independently with constant current and measure the time = capacity.
Based on Arduion Nano.
Youtube Video in English: https://youtu.be/sXIeAKB41Y0
Youtube Video in German: https://youtu.be/Gl1ISn4Dsfc
Software on Github: https://github.com/RainerU/DestructiveBatteryTester
Simple 2 transistor linear current source using PNP transistors and current sink using NPN transistors.
The forward base emitter voltage drop (Vbe) of a bipolar transistor (bjt) is proportional to the log of the base current and rapidly rises to between approximately 0.55V and 0.7V for base currents over a few hundred nA. So for most purposes the Vbe of a bjt when conducting a collector current c...