Current rating problem

[rakibulraju]

I am trying to convert a ac signal of voltage 7v and about 1A current of frequency 2Mhz.when i convert it to dc by full bridge rectifier of general diode 1N4007 .The problem is after converting it into dc voltage is about 5-6v but the current is so low about 10ma.what is the problem.please help me someone.

 

[KeepItSimpleStupid]

I do have to ask, what frequency and what kind of load especially since you said "SIGNAL".

Since Vf is 1 V at 1A, the DC voltage is within range.

You may want to look at a devices from Linear technology and Analog Devices. The AD part will precision full wave precision rectify at high frequencies.

 

[rakibulraju]

I do have to ask, what frequency and what kind of load especially since you said "SIGNAL".

Since Vf is 1 V at 1A, the DC voltage is within range.

You may want to look at a devices from Linear technology and Analog Devices. The AD part will precision full wave precision rectify at high frequencies.

' My circuit frequency is 2Mhz and the load is a resistive load.At the same load it is showing 1A in ac but after converting it is giving current 10ma in dc with the same load.Please suggest me a solution'

 

[alec_t]

What are the source output impedance and load resistor values?

Edit: The reverse recovery time of a 1N4007 is ~ 500ns, making it less than ideal as a rectifier at 2MHz.

 

[MrAl]

Hi,

Yes, as Alec says the 1N400x series diodes are not suited for high frequencies like that so you'll see a terrible loss. You need a Schottky or other high speed diode type. 1N400x diodes were made for line frequency operation like 50 to 400 Hertz. 2MHz is much higher.

 

[KeepItSimpleStupid]

I tried hard last night to find the Analog Devices Part which can do precision rectification, but not power rectification. Sometimes these can be found under Absolute Value circuits.

This product https://www.linear.com/product/LT4320 an Ideal diode bridge controller, which is quite new, but it won't help you either DC-600 Hz

 

[KeepItSimpleStupid]

What EXACTLY are you trying to do?
Do you just want to read the rectified voltage or is that a prerequisite for something else?
Do look for some absolute value circuits using difference amplifiers.
There may be some other techniques out there as well.
I'm still trying to research what I thought I had run across. The only thing close was a precision rectifier using a difference amp that was valid to 10 Khz.

Really, www.analog.com may be your best bet,