MOS/bipolar active input current mirrors with 13-decades gain adjustment range

This paper introduces two new active input current mirror topologies. They present the following advantages with respect to the conventional active input current mirror: (a) one of them does not require stability compensation while the other may require under some circumstances, (b) once they are stable for a given input current level, their input current can be made arbitrarily small, (c) the current mirror gain can be controlled continuously through a gate voltage for a range of 13-decades according to our experimental results, and (d) the circuit can be operated by either biasing the mirroring transistors as MOS or as lateral bipolar devices. One of the current mirrors has been used to build a constant input range OTA whose transconductance can be tuned over 7 decades. This OTA is then used to assemble a gm-C sinusoidal VCO whose frequency can be tuned from 74mHz to 1MHz. To our knowledge this has never been achieved before using gm-C MOS oscillators.