Impulse to charge battery?

[Reynard]

Hi

i'm a newbie here hehe....I need help in designing a charging circuit that is able to store a signal consisiting of random impulses. The impules can vary from 2V up to 20V and the period of each impulse is about 0.1sec.

Anyone have any ideas as in how to store this random series of impulses that i got? My aim is to charge up a small battery.

I have came across Maxim MAX1879 Li+ Pulse Charger chip but i noticed that a constant DC supply is still needed in order to charge a battery by pulse charging. I'm still waiting for my order of this chip to arrive so cannot comment if this chip is able to work for my case...

Cheers
Rey

 

[RadioRon]

What is the source impedance of the thing that supplies the impulse? I will assume it is low because otherwise you have very little power available and if so then it would take an impractically long time to charge up a battery. There are two obvious choices to charge the battery. The first is to let any of the impulses that exceed the battery voltage feed directly into the battery through a rectifier and perhaps a current limiting resistor.


The second is a bit more complicated. You would feed the impulse through a schottky rectifier to a large value capacitor. The charge would build on the capacitor over many impulses until it reached, say, 0.8 volts or more. At that point you can have a switching regulator (boost type) switch on and charge your battery until the capacitor voltage drops below a threshold and then turn the switcher off. I've seen this kind of thing used for charging a battery from a solar cell (I think I saw an app note on Maxim's site, to do with solar cell battery charger circuits.

 

[Reynard]

Thxs for your advice, i will try to work along this idea.