Full wave bridge rectifier by schottky diode

[rakibulraju]

I want to make a full wave bridge rectifier by schottky diode.Will the diagram be same as normal diode or will there be any change?I have not worked with schottky diode before that's why asking..

 

[Ian Rogers]

See here.... There are pitfalls.. https://www.edaboard.com/thread61788.html

 

[mvs sarma]

I want to make a full wave bridge rectifier by schottky diode.Will the diagram be same as normal diode or will there be any change?I have not worked with schottky diode before that's why asking..

if your aim is to use for mains rectification, you must be sure that each such diode the Vr is compatible to the voltage you apply.
secondly , if you try to use a bridge at smps etc where the AC output is at =higher frequency, check whether the capacitance of these diodes comes on your way.
at Higher voltages, there , perhaps , no need to use schottky diodes ass additional voltage drop may not be an issue.
If you are proposing at say 3.3V or lower power supplies of very large current, many people do use mosfets to reduce the on resistance of the rectifying element.
each mosfet would be triggered by the voltage level at the gate by a small extra winding.
try to google for the actual schematic .

 

[rakibulraju]

if your aim is to use for mains rectification, you must be sure that each such diode the Vr is compatible to the voltage you apply.
secondly , if you try to use a bridge at smps etc where the AC output is at =higher frequency, check whether the capacitance of these diodes comes on your way.
at Higher voltages, there , perhaps , no need to use schottky diodes ass additional voltage drop may not be an issue.
If you are proposing at say 3.3V or lower power supplies of very large current, many people do use mosfets to reduce the on resistance of the rectifying element.
each mosfet would be triggered by the voltage level at the gate by a small extra winding.
try to google for the actual schematic .

"if you try to use a bridge at smps etc where the AC output is at =higher frequency, check whether the capacitance of these diodes comes on your way."sir i didn't get it.

'Sir my source is a induced voltage at the secondary of a wireless transfer device of 7 v ac of 2Mhz frequency with current 1A. I need to rectify it and I need a output of 5v and minimum current 500ma.will this serve the purpose?what value capacitor i should use at the output of the rectifier?'

 

[mvs sarma]

i meant that the schottky diodes have high reverse capacitance.
this might become a big problem during a negative half cycle and the cap becomes an unwanted load !

please go thro' high frequency smps designs in motorola smps hand book. i know they listed lot of rectifying diodes and select from that what can suit you at 2MHz

Perhaps power mosfets might better suit if configured in fullwave rectifier mode. You need to select low gate drive mosfets

 

[ronv]

Try something like 1N5817 and 0.22ufd. cap. The bridge is the same.

 

[MrAl]

Hi,

Just a quick note...

I've used 1N5817 diodes for a bridge to rectify the output of a transformer with high frequency (50kHz or above) square waves. That was for a small converter to convert 12v to 9v mostly so i could get electrical isolation from input to output. This is also done on many different types of converters though too. The main reason for using these diodes is because of the higher frequency. If the voltage rating is too limiting however, then you can move to fast recovery diodes.

 

[unclejed613]

if the frequency is 2Mhz, then maybe silicon carbide diodes would be a better choice, as these have zero reverse recovery time. the only real drawback is that the forward voltage is a bit over 1V.

 

[rakibulraju]

if the frequency is 2Mhz, then maybe silicon carbide diodes would be a better choice, as these have zero reverse recovery time. the only real drawback is that the forward voltage is a bit over 1V.

'drawback is that the forward voltage is a bit over 1V.',what does it mean forward voltage drop is 1V.if so as my source is 7v then this 1V loss is a big amount .so what do you suggest?

 

[rakibulraju]

'drawback is that the forward voltage is a bit over 1V.',what does it mean forward voltage drop is 1V.if so as my source is 7v then this 1V loss is a big amount .so what do you suggest?

can you please suggest a model of silicon carbide diode?i am searching it in google and there are many with different catagory .i am confused about which one is perfect for me?

 

[crutschow]

A Schottky diode of the required voltage and current rating should work for what you want. Don't see any reason to use silicon carbide, since they are no faster than Schottky's and have a much higher forward drop. They are mainly used when you need very high voltage, high temperature, and fast devices

For 2MHz at 1A, a 2.5uF capacitor would give about 100mV of ripple.

 

[MrAl]

'drawback is that the forward voltage is a bit over 1V.',what does it mean forward voltage drop is 1V.if so as my source is 7v then this 1V loss is a big amount .so what do you suggest?

Hi,

If your source is only 7 volts then you dont need special diodes, just the Schottky type like 1N5817 or 1N5823 something like that. These have lower forward voltage.

 

[rakibulraju]

A Schottky diode of the required voltage and current rating should work for what you want. Don't see any reason to use silicon carbide, since they are no faster than Schottky's and have a much higher forward drop. They are mainly use when you need very high voltage, high temperature, and fast devices

For 2MHz at 1A, a 2.5uF capacitor would give about 100mV of ripple.

thank you so much

 

[rakibulraju]

Hi,

If your source is only 7 volts then you dont need special diodes, just the Schottky type like 1N5817 or 1N5823 something like that. These have lower forward voltage.

thank you so much

 

[MrAl]

Hi again,

You are certainly welcome

If you are looking for very low forward drop, you might look into the Zetex Schottky diodes. The 2 amp rated ones have very low voltage drop, the lowest i've seen for Schottky diodes. What they do that is different im not sure, but it might have something to do with less impurities in the die. But if 0.5v is good enough then the 1N5817 or similar should be ok. The 1N5817's are good for up to 1 amp, i think the 1N5823 is 3 amps, but there are a number of them in that line with different reverse voltage ratings.

 

[rakibulraju]

Hi again,

You are certainly welcome

If you are looking for very low forward drop, you might look into the Zetex Schottky diodes. The 2 amp rated ones have very low voltage drop, the lowest i've seen for Schottky diodes. What they do that is different im not sure, but it might have something to do with less impurities in the die. But if 0.5v is good enough then the 1N5817 or similar should be ok. The 1N5817's are good for up to 1 amp, i think the 1N5823 is 3 amps, but there are a number of them in that line with different reverse voltage ratings.

hi sir i am using schottkey 1N5817 .the voltage is satisfiable but is not .because i was getting 1A in AC but with same load i am getting 50ma.what can i do?now my converted dc is of 9v and 50ma but i need 5v with 500ma.is there any way to increase current to 500ma as i can sacrifice about 4v from 9v source to get that current?

 

[ronv]

It must be your load doesn't need 500 ma. but only 50. I=E/R. With R being your load.