[SOLVED] Photodiode Amplifier Problem in sunlight

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chippevijaya

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Dear friends,
I am trying to develop a photodiode receiver circuit as shown in attachedfigure. When i placed this in under sunlight the output voltage level is shifted(DC-offset) is happening.
Is there any possibility to reduce the offset of the voltage and try to pull near to zero. This is happening due to photodiode is receiving the sunlight components and turned to high.
Please help me in this.

 

Why don't you refer to known working photodiode amplifiers from literature? Connecting a reverse biased photodiode to a floating OP input without a load resistor is just screwed up.
 
Thank you FvM,
I have connected a resistor from photodiode anode to ground, i think this is the resistor you are talking about.
And please provide me the literature(book names or pdf or they are in this forum).
Please reply me..
 

Try to google: transimpedance amplifier photodiode
You should see circuit schematics how to properly amplify a photodiode signal.

For the sunlight problem, are you familiar with high pass filter? Or AC coupling? Sunlight is basically a constant light or slowly changing light signal, right? So sunlight -> electrical domain should also be slowly changing, which can be considered as DC signal. Just AC-couple or high pass the output of your amplifier output. Then you should be fine. Be aware of amplifier saturation(output voltage hitting the maximum output voltage) because sunlight can be very intense when shined directly to photodiode.
 

Thankyou tinska....I will try your suggestion and reply soon....
 

chippevijaya said:
Thankyou tinska....I will try your suggestion and reply soon....
Click to expand...

Tinska, as per your suggestion it is removing the dc-offset and able to send the pulses. I used a series capacitor(1uF) and a resistor(10-ohms) at photodiode output, and after that a inverting transimpedance amplifier(OPA380). (connected as per ac-coupling inverting amplifier in )
I am facing a different problem now. Actually my photodiode is receiving the 60ns pulses. Sometimes the pulses are missing and a noise is observing at the output of amplifier, due to this comparator is giving a default high.
Can you suggest me how to choose the AC-coupling to send the 60ns pulses.
 

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