Low-swing cmos input circuit

Abstract

The invention relates to a CMOS input circuit for receiving low-swing input signals, which is an alternative to the CMOS input circuits as known from the prior art. The CMOS input circuit according to the invention comprises a leveling circuit (LC) that is constructed for arranging, under control of a voltage associated with an output voltage of a CMOS input stage (Inv), a leveling transistor (M) which is located in a supply path of the CMOS input stage (Inv), (i) as a forward-biased diode-connected transistor for regulating the voltage on a source of the CMOS input stage (Inv) for reducing the gate-source voltage of a switching transistor (M, M) in the CMOS input stage (Inv), when an input voltage of the CMOS input circuit assumes a level associated with a first logical level causing the switching transistor (M, M) to be switched off, and (ii) as a conductive path when the input voltage assumes a level associated with a second logical level causing the switching transistor (M, M) to be switched on. The invention also relates to an Input-Output circuit, an electronic circuit and a semiconductor device comprising such CMOS input circuit. The invention provides an alternative to known CMOS input circuit that make use of a diode-connected transistor that is short-circuited in case of one of the input voltage levels. An advantageous embodiment of the invention incorporates a positive feedback mechanism that makes the circuit more suitable for low supply voltages.