10
\$\begingroup\$

I was designing a basic power supply with frequency ranging from 50-60Hz and thought about using this bridge rectifier KBPC50005. I cant seem to understand the range of input frequencies it can take, its application notes have graphs made for 60Hz load, my input supply's frequency is 50Hz, and i think it might work but this lead me to this question that how can I be sure about it? Will it really work?

What if my input signal's frequency ranges to 100Hz or 800Hz? Will this rectifier work? How low or high frequency can it tolerate? Or to be more general, what are the factors on which the input frequency characteristics of any bridge rectifier depend? Any ideas?

\$\endgroup\$
2
  • \$\begingroup\$ @Andy Aka kindly pointed me to this 1N4007 datasheet that shows a reverse recovery time of 30 uS!. That would be noticeable but usable at 1 kHz and by 10 kHz it would be getting "extremely sad indeed". Sticking with up to 400 Hz supplies (aircraft) they would be good enough for most purposes. Your bridge is "quite likely" similar. (For many values of "likely :-) ). \$\endgroup\$
    – Russell McMahon ♦
    Feb 3, 2015 at 11:28
  • \$\begingroup\$ But these specifications are for a diode, what if I am using a discrete IC for a bridge? Like the one I mentioned earlier. There is no detail of the recovery time over there. \$\endgroup\$
    – alexhilton
    Feb 4, 2015 at 2:45

1 Answer 1

Reset to default
8
\$\begingroup\$

A good question - fortunately also the answer is nicer than some - the rectifier cited can easily handle frequencies from DC to well above 60 Hz.

Rectifiers intended for mains use usually do not have specifications provided relating to frequency capability as they will easily deal with any "normal" non switch mode applications. The highest they are liable to usually be used for are 400 Hz "aircraft" supplies. They are liable to work about as well at 10 kHz. Above that you may want to start checking.

Relevant parameters may include capacitance, reverse recovery time, stored charge ... and probably a few more.

"Fast Recovery" diodes usually have recovery times less than 1 μs. Recovery time is ~= the time for forward current to fall to zero after applied voltage changes from positive to negative.

The diode below relates to an FET internal body diode but is a nicer illustration than some others available. From here

enter image description here

\$\endgroup\$
4
  • \$\begingroup\$ Okay, so you are saying that it would work on frequencies till 400 Hz? But this datasheet only has the junction capacitance information (if that's one parameter to look for), what about the others? How did you conclude that it would work for frequencies till 400 Hz? Is there some kind of formula to calculate this? \$\endgroup\$
    – alexhilton
    Feb 3, 2015 at 9:21
  • \$\begingroup\$ @alexhilton I said it would "probably" work to 10 kHz. I noted that there was no specific information because they expect such devices to be used well below its spec in this respect. Anyone wanting to eg PWM FETS at 10 KHz knows that they want switching times close to 1uS or less and will go looking for diodes to suit. Any power system known to man (this man anyway :-) ) that is not a "switching power supply" is under 1 kHz and liable to work with any modern silicon diode. Here is the datasheet for 1N4007... \$\endgroup\$
    – Russell McMahon ♦
    Feb 3, 2015 at 9:58
  • \$\begingroup\$ .... @alexhilton - The 1N400x is THE utility 1A diode series. Look at note 2. Capacitance measured at 1 MHz. Wow. \$\endgroup\$
    – Russell McMahon ♦
    Feb 3, 2015 at 9:59
  • \$\begingroup\$ hey i see it too now :-), so turns out they do mention stuff, but hey is there any formula or criteria for future reference? How to select a bridge for some required frequency? \$\endgroup\$
    – alexhilton
    Feb 4, 2015 at 2:43

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

Not the answer you're looking for? Browse other questions tagged or ask your own question.