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
    2
    0
    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.
     
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