Im looking for a suitable IC to charge electrolytic capacitors to a voltage of 30-40V in constant current mode. As an input I intend to use a 12V voltage regulated power supply.
Regarding voltage regulators, there are not many around which go up to 40V. So far, I have found the LM2733, but the output current is only around 300 mA. Maybe I have to use an IC with external switch?
To summarize:
Vin = approx. 12V (regulated)
Vout max = 38V
IC cost: < $3
Constant Current Mode
I > 0.5 A
Any suggestions for specific ICs or how I can find suitable one out of the 10k controller ICs digikey has listed?
Yes, off course I will need additional components. I‘m looking for an IC as the main component for a boost converter circuit, which works with 12V input voltage and delivers at least 0.5A of current.
I have no experience in power electronics and therefore I hope for some specific information regarding suitable components. From this point I think to have a chance to continue, but currently I‘m lost in choosing a suitable IC.
Maybe "ancient" MC34063? Up to 40 Vdc and (crude) input current limiting? I think you want constant input current to have constant power. AN920 MC34063 DC DC converter app note.PDF (416.3 KB)
Believe me or not, I had a look at many application notes. I found interesting ICs, but not one which fullfills all requirements.
I had a look at: TPS61170, LM5155, LM2577, LM 2587, MC33063, LT1270, LMR64010. I also had a look at capacitor charge ICs such as LT3750. The latter is too expensive and the output voltage is "high voltage", which I don't need/want.
@ Smajadalf
I came across the MC34063. Voltage is ok, and it's cheap. It's beeing said, this IC is not suitable for sudden changes of the load. Don't know in detail what that means.
I don't need constant input current. I want to charge a capacitor and read that constant current is the way to do so, because it's faster and more efficient.
Don't understand your point. If I wan't to charge to a higher voltage, there is always need for a converter circuit.
Capacitor charge at constant voltage is limited to 50% efficiency. This limit does not exist for CC.
@ DrDiettrich
I did not reach the point to choose diodes and inductors. Don't see how that makes sense, if I have not found a suitable IC yet?
Look at modules for LED lighting. They should be constant current in the appropriate voltage and current range, perhaps. 12V input boost supplies might be harder to find, though.
Note that ~40V output at 500mA is going to need close to 2A@12V input.