Converting 12-220V to 12V?

Question

Are there any Analog/Maxim (I couldn't find a switching regulator with these characteristics on their websites) ICs that can step-down a voltage between 12 and 220 V (coming from a generator) to a stable 12V?

Thank you!

Answer 1

Wow, this is a tough one. First, there is clearly no component that would cover the whole range. Due to huge investment that is required for an IC development, any such component is designed for specific market. Although each manufacturer will try to support as many applications as possible, nobody will invest in such small niche. I can say it's small for several reasons, and please, note all of them:

1. In all my career i did not see such requirement.
2. Applications for lower voltages are made cheaper and simpler, while for higher voltages there are special components.
3. Low and high voltage not only differ electrically. It takes very different expertise to design low and high voltage schemes, so vendors will address one of the two domains, but rarely both.
4. This is maybe most significant consideration rarely an electromechanical device effectively covers such wide range. Motors "feel good" in certain RPM, generators have better power output in certain RPM, etc. This is why you see gears on them, this is why for high velocity there are specially optimized motors, etc.

So first of all, check your requirements. Probably your life will be easier, if you will define simpler range, like 90V to 350V.

Practically, you will have to rectify the input (with diodes and capacitors), then most of the range will be covered by ST micro's viper. The rest may be overlaid by Onsemi or TI high voltage DC/DC.

Then you will have to select the input. It should probably be a relay that will switch the source, and some kind of low power comparator to be powered by resistor and LDO from both sources connected with diodes...

I believe, and hope that you will just drop the lower part of your input range.

Answer 2

One possibility is to have a boost converter bypassed by a diode. When the output is 95 V or above, it does nothing (the raw voltage is just passed to the output thru the diode). When the output drops below 95 V, the boost converter runs and makes 95 V from the 12-95 V input.

Now use that to run a regular "universal input" off the shelf 12 V power supply.

However, read what Gregory said carefully. Most likely it would be better to avoid this kind of kludge by re-thinking the overall system.

If the generator produces 240 V at full speed, then the power available when it's running so slowly to produce 12 V is probably not worth bothering to capture. Think about what you really need carefully. Try to see if you can transform the problem into driving a 90-240 V universal input 12 V power supply.

Answer 3

In the industrial controls business, it's not unheard of to have a range of < 20VDC to >240VAC, but 12VDC might be asking a bit much-> ~20:1.

I think it could be done, with fairly miserable efficiency, by using a separate controller chip that does not enforce too low a UVLO level, but that's about as far as I can take it without specs (and even then..).