Reducing resistive losses setting Iref of a current mirror?

Discussion in 'The Projects Forum' started by transcendent12, Jul 19, 2012.

  1. transcendent12

    Thread Starter New Member

    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.