Low power high output impedance high bandwidth QFGMOS current mirror

Abstract

Current mirror is a basic block of any mixed-signal circuit for example in an analog-to-digital converter. Its precise performance is the key requirement for analog circuits where offset is a measure issue. The key parameter which defines the performance of current mirror is its input/output impedance, input swing, and bandwidth. In this paper, a low power design of current mirror using quasi-floating gate MOS transistor is presented. The proposed current mirror boosts its output impedance in range of giga-ohm through use of regulated cascode structure followed by super-cascode. Another improvement is done in reduced input compliance voltage limits with the help of level shifter. The proposed current mirror operates well for input current range 0–700μA with an input and output impedance of 160Ω and 8.55GΩ respectively and high bandwidth of 4.05GHz. The total power consumption of the proposed current mirror is about 0.84mW. The low power consumption with enhanced output impedance and bandwidth suits proposed current mirror for various high-speed analog designs. Performance of the presented current mirror circuit is verified using HSpice simulations on 0.18μm mixed-mode twill-well technology at a supply voltage of ±0.5V.