Integrated circuit having first and second internal circuits controlled by a common input terminal
AssigneeU.S. Philips Corporation
InventorsWerner F. Thommen, Werner Fehr, Arpad Korom
Life of this patent
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Abstract
In order to enable two different internal circuits to be controlled from one input pin of a C-MOS IC said pin is connected directly to an input of a first circuit and via the emitter-collector path of a transistor to the input of a second circuit. The base of this transistor is connected to one of the supply voltages, so that this transistor can conduct only when the voltage on said input pin is higher or lower than the positive or negative supply voltage respectively.
Claims12
An integrated circuit comprising an input terminal for the application of signals to a first circuit, first and second supply lines for supplying power to said first circuit, a first transistor having first and second main electrodes that define a current path in the transistor and a control electrode for controlling the current flow in said transistor current path, means connecting the control electrode to one of the supply lines, the first main electrode to an input of a second circuit which is coupled between said first and second supply lines, and the second main electrode to said input terminal, the conductivity type of said transistor being such that the transistor cannot conduct when the voltage level at said input terminal lies between the voltages on said first and second supply lines.
An integrated circuit comprising, an input terminal for applying signals to the integrated circuit, first and second voltage supply lines, first and second circuits coupled to said first and second supply lines to be energized thereby, first means coupling a control input to the first circuit to said input terminal, a transistor having first and second main electrodes that define a current path in the transistor and a control electrode for controlling the current flow in said transistor current path, and means connecting the control electrode to the first supply line, the first main electrode to a control input of the second circuit and the second main electrode to said input terminal, the transistor being of a conductivity type whereby it is normally cut-off so long as an input signal voltage applied to the input terminal lies in the range of voltages intermediate the voltage levels on said first and second supply lines.
Dependencies are inferred from the claim text.