Solar Power Sequence Control

Problem: as solar power turns on in the morning it acts like a gradually increasing current source. If I try to power a microcontroller with it (e.g. AVR) then the MCU will hiccup (on and off) until enough current is constantly available. Unfortunately such a poor power up sequence can latch-up CMOS devices. Using two TLVH431 a 6V and 6.5V set-point is made. At 6V the battery is connected, then charged to 6.5V, it is not a full charge, but this is when I want to start the MCU. The Load (100 Ohm) will stay latched on until the battery drops bellow 6V again. Adjust 5.5V Zener over the range 1 thru 7 Volt to disconnect battery and make sure the battery does not leak current, that is what the strings of diodes are for. Also, the 4V Zener has over 1uA leakage current so I have to use a diode string in those places of the real circuit also. Adjust 6.4V battery to 6.6V to connect load. Note: open the current source switch before lowering battery voltage bellow 6V or simulation will stop. Circuit board(s) I am working on with this: http://epccs.org/indexes/Board/CC01/

published 9 years ago