US 5,397,946 AGranted

High-voltage sensor for integrated circuits

AssigneeTexas Instruments Incorporated

InventorsPhat C. Truong, Tim M. Coffman, Sung-Wei Lin, T. Damodar Reddy, Dennis R. Robinson

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Abstract

The CMOS high-voltage sensor circuit has a voltage reference including, for example, of four N-channel MOS transistors; one pass-gate P-channel transistor; one current-mirror P-channel MOS transistor; and a conventional high-voltage sensor including, for example, of two P-channel MOS transistors and one N-channel MOS transistor. The sensor circuit of this invention generates a high-voltage signal at the output if the input voltage is greater than both the reference voltage plus two P-channel threshold voltages and the supply voltage Vcc plus two P-channel threshold voltages. The power-up or power-down sequence may be in any order without adversely affecting the operation of the circuit of this invention.

Claims20

Dependent claims

A high-voltage sensor circuit for an integrated circuit, said integrated circuit including a connection pin, a supply-voltage pin and a reference-voltage pin, said sensor circuit comprising:

a first transistor with a first source-drain a second source-drain and a gate, said first source-drain of said first transistor coupled to said connection pin;
a second transistor with a first source-drain a second source-drain and a gate, said first source-drain of said second transistor coupled to said second source-drain of said first transistor, said gate of said second transistor coupled to said supply-voltage pin;
a third transistor with a first source-drain a second source drain and a gate, said first source drain of said third transistor coupled to said connection pin, said gate of said third transistor coupled to said gate of said first transistor;
a fourth transistor with a first source drain a second source-drain and a gate, said first source-drain of said fourth transistor coupled to said second source-drain of said third transistor, said gate of said fourth transistor coupled to said gate of said second transistor;
a fifth transistor with a first source drain a second source-drain and a gate, said first source-drain of said fifth transistor coupled to said second source-drain of said fourth transistor;
said second source-drain of said fifth transistor coupled to an output, said gate of said fifth transistor coupled to said second source-drain of said second transistor;
and
a voltage reference circuit coupled between said gate of said fifth transistor and said reference-voltage pin.

5 more elements

Dependencies are inferred from the claim text.