Powering mains-voltage LED Christmas lights from a 12 volt battery
In this article I will present an inverter circuit I built to power mains-voltage LED light strings from a 12 volt battery. Unlike a traditional inverter, this device operates at a higher frequency, eliminating flicker in cheap LED light strings. The device can also switch the output of the inverter through a TRIAC, allowing the device to be programmed to vary the brightness of the light string. Depending on the configuration of the LED lights in the string, it can also vary the brightnesses of different parts of the LED string independently of one another. The schematic can be downloaded here and the program for the ATTiny can be downloaded here Principle of operation Generating the high voltage This inverter uses a transformer to generate a high voltage from a 12 volt power supply. This is done by switching the low-voltage coil of the transformer through an H-bridge, which consists of 2 N-channel MOSFETS and 2 P-channel MOSFETS: On the left, we have a 500Hz source that drives