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Feb. 26, 2011
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  • Orphic.Mysteries commented on krmartin3's instructable DC Boost Converter8 months ago
    DC Boost Converter

    It is difficult to get any useful current at 6v from a 100mV source. Even with a 1A source @ 100mV, you'd get maybe 10mA@6V of usable reliable power from any homebrew circuit at 80% efficiency (13mA of theoretical supply would be pushing the boundaries of good engineering margins for a circuit that actually uses 10mA. Remember: good margins often include a +/- count as well as a +/- percentages; it's easy to lose 1-2 mA regardless of the %age, especially for analog circuits. Digital chips/circuits are often more optimized for high input/output impedances (changes in I/O voltage cause transient loads on the power rails, and noise, but these can often be tolerated through careful filtering/bypass/routing/etc., but these rarely use >5V.HOWEVER, if you can design your circuit to work at 5v, there are some useful energy harvesting ICs that can provide reliable regulated current from inputs as low as 20mV! I've used the LTC3108 and LTC3109 for circuits with low continuous current (more useful) or larger intermittent current needs (i.e. an energy harvester may harvest continuously 24/7 to power a sensor and RF transmitter that may only wake up and transmit for 1 millisecond each minute: even a 1 microamp continuous source can provide milliamps of power for 1 ms/min)The LTC3108/LTC3109 also directly provides a wide range of power storage (battery or capacitor charging) and management functions useful for digital circuits or microcontrollers (TI's MSP430 MCU family in particular, draws very little current)

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