A novel dual-modulation design low input impedance current comparator

This paper presents a new current comparator with a novel dual-modulation concept. The dual modulation concept has the ability to increase the accuracy quite substantially. The output voltage range still reaches its maximum peak value of 1.2V when the differential current is only 0.6 nA with a 3.3 V supply voltage. In addition to high-accuracy, the design reduced the input impedance of the proposed current comparator to 1/(gm²ro) even without the use of an operational amplifier (OPA). Moreover, the novel current comparator was implemented using TSMC 0.35 μm Mixed-Signal 2P4M Polycide 3.3V models with an active area of 0.0024 mm².