Reducing resistive losses setting Iref of a current mirror?

Thread Starter


Joined Dec 9, 2011
Hi all.

I'm designing some ultra low power super regenerative transceiver using off the shelf transistors.

One of the things I must deal with is controlling the tail current of a differential pair. At the moment I just have a current mirror with Iref determined by voltage through a resistor. Unfortunately, this resistive loss is quite high. Especially as the real world demands more bias current to make my design work than Pspice simulations.

I'd like to know if there is a good way of setting Iref without relying heavily on the resistor.

Perhaps would using a common collector amplifier (voltage follower) to amplify a small current to set Iref be a decent idea? Note that an accurate voltage reference is some what out of the question. Maybe just an digital/analog output +3v/0v (essentially modulating current source on and off). But i need to be able to tune output current for circuit testing i.e. using a 100k + resistor.