The Howland Current Pump with balanced-bridge resisters

[engr_joni_ee]

Hi, I have found this article that describes how to get current source with Op-Amp.

The Howland Current Pump - Technical Articles

The Howland current pump, invented by MIT’s Professor Bradford Howland in the early 1960s, consists of an op-amp and a balanced resistor bridge and puts out current in either direction.

www.allaboutcircuits.com

If I chose R1 = R2 = R3 = R4 = 3.3 K Ohm and input voltage Vi = 3.3 V then theoretically I will get 1 mA current across the connected load. How much precise this current source ? Would it worth if I use this 1 mA current to setup PT1000 temperature sensor application ?

 

[danadakk]

You have to do an error analysis to answer your question.

- R accuracy
- OpAmp Vos, Aol, PSRR, Noise
- Temperature effects

Best way is to do this, followed by sensitivity analysis to focus
attention to biggest errors first.

https://www.ti.com/lit/ml/sprp524/sprp524.pdf (This focuses on filter, but same principles
apply to DC analysis).


Regards, Dana.