To power an amplifier, I use a lipo battery 3.7v (4000mah) or two 18650 batteries 3.7v (4000mah) in parallel with a DC/DC boost converter that boost the voltage to 24.2 volts. The circuit performs pretty well.
On the load side (output) of the DC/DC converter I use a 25V 4700uF capacitor which introduce a problem, inrush current (when charging) for a second or so when switched on. Not a healthy situation, want to avoid this.
I read allot about inrush current and there seem many options to fight against it but it is not clear to me which is the best one. I hope it can be simple as putting one 'simple' component into the circuit without loosing too much effort. The capacitor is really helpfull, especially at high volume with much bass.
So I came allong the NTC and PTC thermisistors. The NTC does not fit the situation and could be risky when the device is switched off and on again when the NTC is not cooled down, so it doesn't eliminate the inrush current. The disposed heat (wasted energy) is also something I don't like.
The PTC one is the opposite, but how fast is it? Do it really fight inrush current? Because the PTC heats up when there is much current but I suppose it takes some time to heat up (and therefore draw some current) before it enables protection?
Before I decide to buy a bunch of these PTC thermisistors, I like to hear/learn/know some advise of you, professionals.
Questions I have:
- Does a PTC avoid inrush current from the start (how accurate)?
- Does a PTC influence the performance of the capacitor (or the whole achievements of the PSU)?
- The amperage, is this the maximum current the PTC can handle or is this the maximum amount of current it will use?
The next question is, will it help to divide the capacitance into several capacitors with the same amount in parallel to reduce inrush current? Or at least to reduce the time of the inrush current.