For some simple led curcuits I would like to use just a single AA cell. Are there any simple low part count _discrete_ solutions for a converter that has an efficiency of >50% with a standby current or no load current of less than 1mA? Charge pump is preferred, but if it needs a single coil it's also ok. Thanks in advance.
-- Dipl.-Inform(FH) Peter Heitzer, peter.heitzer@rz.uni-regensburg.de HTML mails will be forwarded to /dev/null.
Connect BJT base through 1k to primary of small transformer (made on small bead with a few turns and ratio 1:1). Other end of the same wind connect to +1.5V. The other turn connect between +1.5V and the collector. Emitter connect to the ground. LED connect between collector and the ground in parallel with small cap. LED should for a few hours. Replacing BJT with MOS with low Vgsth may even improve efficiency. ed to /dev/null.
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