Voltage clamping current mirrors with 13-decades gain adjustment range suitable for low power MOS/bipolar current mode signal processing circuits

Low power current mode signal processing circuits require the two following conditions: (a) use of current mirrors to replicate and amplify/attenuate current signals, and (b) voltage clamping of those nodes with high parasitic capacitances so that the smallest current levels do not introduce unacceptable delays. In this paper we introduce two new active-input current mirrors that clamp their input node to a given voltage and which do not require compensation circuitry for stability. In conventional active-input current mirrors, input current cannot be made arbitrarily small, because this would produce oscillations. In the structures proposed in this paper current may spawn beyond six decades without requiring any compensation. Furthermore, the two new proposed current mirrors, if operated in weak inversion, can be made to have a continuously voltage controlled gain with a tuning range of up to 13 decades. The proposed active-input current mirrors can be operated either with MOS or bipolar transistors. Experimental results that attest these facts are provided.