Offset - Zener or Linear Regulator

[TheLacasse]

Hi I'm designing a preamplifier for a class D amplifier using an op-amp the LM324 and I need an offset voltage of 2.5V. I would like to know what should I use to make the offset a zener diode with a voltage divider, a linear regulator like a 7805 with a voltage divider or if there is something better let me know. I want the most efficient and easier way to do it.

Thanks
P.S. I don't normally speak English

 

[(*steve*)]

There are many 2.5V voltage references available.

The important question is whether you need 2.5V or half of your supply voltage (assuming this is 5V).

 

[TheLacasse]

There are many 2.5V voltage references available.

The important question is whether you need 2.5V or half of your supply voltage (assuming this is 5V).

2.5V because my supply voltage will be a 9V battery.

 

[(*steve*)]

A 2.5V reference is very similar to a linear regulator. The main difference is that they are designed to deliver an accurate voltage rather than provide power to a circuit.

There are also those like zener diodes (the TL431 is an example of this).

In your case the TL431 may result in a higher component count, and the need for adjustment to get the correct voltage.

 

[AnalogKid]

Side comment - the LM324 is a true workhorse, but it is not a particularly high fidelity device. Its input stage noise, output crossover distortion, and limited gain-bandwidth were not great in the 70's and are easily surpassed today.

ak

 

[BobK]

What is the reason for needing 2.5V. Normally, when using single supply opamps, one simply splits the supply voltage to give the largest headroom.

Bob

 

[TheLacasse]

What is the reason for needing 2.5V. Normally, when using single supply opamps, one simply splits the supply voltage to give the largest headroom.

Bob

I have an input voltage of approximately 1.0V ac that I want to amplify to 2.5V ac with a offset voltage of 2.5V. I want the output voltage to be between 0V and 5V but I just realized that the output cannot reach the VCC- in my case the GND.

 

[TheLacasse]

I was thinking of something like this but it won't work because the output of the LM324N cannot reach the GND because I'm using a single supply. I think I will change the offset of 2.5V for an offset of VCC+/2 and then at the output I will put coupling capacitor with an offset of 2.5V (high pass filter). Will it be better?