Self-controlled 4-transistor low-power min–max current selector

Four cross-coupled MOS transistors operating as switches implement a very compact, fast, low-power and precise minimum and maximum current selector. Local positive feedback allows the circuit to work without the need of any control inputs and ensures very high sensitivity. Experimental results confirm the simulations and the analyzed second-order effects. Applications include min–max current selection and precision differential rectification. An application example of the cell to build a similarity circuit is reported.