Voltage reference that can sink upwards of 100mA

Hey all,

I have 7 analog channels each of which is going to be driving a 50mA peak signal through a load. The problem is I was planning on using a single ended supply to avoid an extra dual rail power supply. So the driver is powered by a 5V single supply and will be centered around the midpoint of 2.5V. Therefore the other side of the load will be connected to this 2.5V source to avoid a DC current through the load which is a coil I don't want to create a DC field. My problem is that I was originally planning on using a voltage rail splitter or linear regulator to provide this reference but I cant find a splitter than can provide that much current and my understanding is that a linear regulator can only source current not sink it.

If I want to stick with the 5V single supply is my only option to use a switching power supply to generate the 2.5V bias point?

Thanks in advance!

-Kevin

Hi,

I´d use a class AB audio amplifier.
Some of them are already mid scale biased.

Look at TPA301, SSM2211 or similar.

Klaus

I guess my issue isn't biasing the output of my driver its where I'm driving current into. The "50 Ohm Resistor" in my circuit is actually the offset cancellation strap of a Magnetoresistive element. At the worst case scenario I need to drive it with a 50mA peak sine wave at approximately 1kHz. If I ground the negative side of the load I'm driving DC current through the strap which creates an unwanted DC field. Therefore I've been simulating this circuit with a 2.5V supply connected to the negative side of the load and everything looks good other than how I can practically realize this circuit. If I use a Buck converter to bias that point at 2.5V will it be capable of sinking as much current as it can source?

Hi,

The given audio amplifiers ... (without any signal connections) will output VCC/2.
If your supply voltage is 5V then the output is 2.5V.
They are able to easily sink and source currents of 100mA.

I thought this is what you need.
This is a simple - one part - solution.

***
But you have an OPAMP with additional bias.

With the given audio amplifiers you may replace this OPAMP by the built in second amplifier.
So it´s not only a "mid scale regulator" ... it´s a complete solution for your application.

It may easily drive your 50 Ohms load with low distortion.

Klaus

Ah I misunderstood you, I though you were offering those amplifiers as a replacement for my driver not for the "mid scale regulator". Thank you for the suggestion, I'll take a look at this as a possible solution.

-Kevin

Hi,,

Again:
It´s all in one.

One single IC for both:
* mid scale regulator
AND
* your amplifier.

Klaus