US 4,080,539 AGranted

Level shift circuit

AssigneeRCA Corporation

InventorRoger Green Stewart

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Abstract

A gating means couples excitation signals to the input of an inverter which is connected between first and second power terminals. Positive feedback means is connected between the input and the output of the inverter. In response to an excitation signal, whose level is intermediate the levels of the operating voltages applied between the first and second power terminals, the inverter output is driven to the potential at one of the first and second power terminals while the potential at the other one of the first and second power terminals is applied to the inverter input. The gating means, conductive during transitions of the excitation signals from one level to another, does not conduct in the steady state condition, whereby a potential at the inverter input of higher amplitude than the excitation signals is not coupled back to the source of excitation signals.

Claims12

Dependent claims

The combination comprising:

first, second, and third power terminals for the application thereto of first, second, and third operating voltages, respectively;
said second voltage having a value intermediate the values of said first and third voltages;
an input node adapted to receive input signals making transitions between a first level, corresponding to said first voltage, and a second level;
first and second inverters, each inverter having an input, an output, and two power terminals;
means coupling said first and second power terminals to respective ones of said two power terminals of said first inverter;
means connecting the input of said first inverter to said input node, the output of said first inverter being clamped to said first voltage when the input signal is at said second level and being clamped to said second voltage when the input signal is at said first level;
means coupling said first and third power terminals to respective ones of said two power terminals of said second inverter;
a first gating means connected between the output of said first inverter and the input of said second inverter for coupling to the input of the second inverter, via a low impedance path, the voltage transitions, at the output of the first inverter, going from said first voltage to said second voltage;
said first means exhibiting a high impedance and being nonconductive when the output of said second inverter is at said first voltage and its input is at said third voltage;
regenerative feedback means, connected between the output and the input of said second inverter, for driving the input of said second inverter to the voltage at said third power terminal and setting its output to the voltage at said first power terminal in response to the application to said second inverter of said transitions going from said first voltage to said second voltage;
and
a second gating means including a transistor having a conduction path and a control electrode, means connecting said control electrode to said input node and means connecting said conduction path between the input of said second inverter and said first power terminal for clamping the input of said second inverter to said first voltage when the input signal is at said second level.

9 more elements

A level shift circuit comprising:

first, second, third and fourth power terminals for the application thereto of first, second, third and fourth operating voltages, respectively, the levels of said first and second voltages being intermediate the levels of said third and fourth voltages;
an input node adapted to receive signals making transitions between first and second levels, intermediate the levels of said third and fourth operating voltages;
first and second inverters, each inverter having an input and an output and two power terminals for the application therebetween of an operating voltage;
means for applying said first and second voltages to respective ones of the two power terminals of the first inverter;
means for applying the input of said first inverter to said input node;
means for applying said third and fourth voltages to respective ones of the two power terminals of the second inverter;
regenerative feedback means connected between the input and the output of said second inverter;
and
gating means comprising two parallel paths connected between the output of said first inverter and the input of said second inverter, each path including two IGFETs having their conduction paths connected in series;
with the gate electrode of one transistor of each path being connected to the output of said second inverter and the gate electrode of the other transistor of each path being connected to said input node.

7 more elements

Dependencies are inferred from the claim text.