Single-point-detection slew-rate enhancement circuits for single-stage amplifiers

Most slew rate enhancement circuits can either be used in current-mirror amplifiers or folded-cascode amplifiers, but not in both. In this paper, a new class of slew rate enhancement (SRE) circuits is proposed. By using a single-point detection (SPD) technique at the active load device of the core amplifier to sense the fast signal transient, the new SRE circuits can be used in both current-mirror and folded-cascode amplifiers. In addition, the simple SRE circuits serve as a plug-in feature to the core amplifier and do not affect its original small-signal frequency response. Implemented by an AMS 0.6 μm CMOS process, the current-mirror amplifier with SRE circuit occupies an area of 0.027 mm² and achieves 1.5 V/μs slew rate with 470 pF capacitive load while only dissipating 90 μA total static current. Similarly, the folded-cascode amplifier with SRE circuit occupies an area of 0.03 mm² and achieves 1.52 V/μs slew rate with 470 pF loading while only 84 μA total static current is dissipated.