Circuit for detecting high voltage level in MOS technology
AssigneeSGS-Thomson Microelectronics S.A.
InventorsJacek Kowalski, Christophe Chevallier
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Abstract
A circuit for detecting the high voltage level of a voltage V.sub.cc in MOS technology comprises a voltage source made of at least one P-type MOS transistor and one N-type MOS transistor, and delivers an output voltage VA such that: O<VA<VTN if V.sub.cc .ltoreq.C and VA=Vcc-C+VTN if V.sub.cc >C, VTN being the threshold voltage of the N-type transistor and C being a substantially constant voltage. The circuit further comprises means for delivering an output logic level which switches over when the high voltage level of the voltage V.sub.cc exceeds a predetermined threshold, said means being connected to the voltage source. The invention can be applied to EPROMs or EEPROMs.
Claims7
A device for detecting a high threshold voltage of a supply voltage in a circuit constructed by MOS technology on a substrate, said device comprising, between a supply connection which receives said supply voltage and a ground connection, a serially connected arrangement of a first conductivity type first transistor (TN1) and a reference voltage source, said reference voltage source comprising a plurality of transistors of a second conductivity type opposite said first type, each of said plurality of transistors being made into a respective separate well made in said substrate, said well connected to a source electrode of a respective one of said transistors made in this well, each of said plurality of transistors having a gate electrode and a drain electrode connected together.
Dependencies are inferred from the claim text.