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US 4,791,322 AGranted
TTL compatible input buffer
AssigneeGazelle Microcircuits, Inc.
InventorsAndrew C. Graham, Mark E. Fitzpatrick
Life of this patent
Estimating the term…
Abstract
This invention discloses a TTL compatible input buffer which includes means for preventing appreciable current flow into the buffer circuit upon input voltage being supplied to the input signal lead which is substantially above the voltages supplied to the voltage supply terminals of the circuit.
Claims12
An input level shifter circuit having a shifter input signal lead for receiving an input signal, a shifter output signal lead for providing an output signal, a first voltage supply terminal, and a second voltage supply terminal, comprising:
- first and second transistors;
- said first transistor having a first current handling terminal connected to the first voltage supply terminal, a control terminal, and a second current handling terminal;
- said second transistor having a first current handling terminal connected to the second current handling terminal of the first transistor, a control terminal, and a second current handling terminal connected to the second voltage supply terminal;
- the shifter output signal lead being connected to the first current handling terminal of the second transistor;
- the shifter input signal lead being connected to the control terminal of the first transistor through a diode reverse biased in the direction of the input signal from the shifter input signal lead to the control termimal of the first transistor;
- and
- load means connected to the first voltage supply terminal and the control terminal of the first transistor.
4 more elements
Dependencies are inferred from the claim text.