Re: Pummer Circuit Idea/Question(s) (kinda long)
- I will have more time later but here is a small contribution to the
discussion. High peak supply current pulses are a major drawback of
using 74HC240 inverters for construction an oscillator. Twice each
cycle, the slow changing voltage at the R/C input node passes through
the threshold and this is accompanied by a significant supply current
pulse. The uPower CMOS oscillator
overcomes this problem by buffering the CMOS input with a NPN
transistor. This reduces the peak supply current by 2 orders of
magnitude from several mA to several tens of uA.
In this simple version the output is asymetric and is used here to
drive a voltage tripler to drive a white or blue LED from a 2.5V dark
turn on controlled solar charger using a super cap or two NiCd
The voltage at tp1 and tp2 are normally high and low respectively.
When the oscillator briefly changes state, tp1 and tp2 outputs go low
and high respectively. This causes the two 1000uf caps to charge to
2.4V with tp3 at 2.4V and tp4 and 100mV. When the oscillator changes
back, tp1 and tp2 are high and low again while tp3 is "pumped" up to
4.9V (max) and tp4 is "pumped" down to -2.4V (min). The difference
between tp3 and tp4 is theoretically 7.3V, almost 3x the solar
supply. In fact the LED will turn on and clamp this difference
voltage to about 5V while the LED emits a fast rise, slow decay light
More ideas later.
--- In email@example.com, "Mike Scharf" <thelizard6969@h...> wrote:
> Good call. I had thought about that briefly. It sounds like exactly
> the type of circuit that would work, although more costly it would
> VERY efficient. I just seem to have trouble making even the
> circuit operate using FET's. But that is one of my weaker areas
> will be working on soon!
> Thanks Neil
> --- In firstname.lastname@example.org, "Neil" <neil@r...> wrote:
> > Hi Mike,
> > I think you are describing the holy grail of pummers here.
> > One thought that I have had is to employ additional power in the
> > a few series photodiodes.