Back to results
US 8,138,813 B2Granted
Interface circuit
AssigneeRenesas Electronics Corporation
InventorHiroshi Inose
Life of this patent
Estimating the term…
Abstract
An interface circuit according to one aspect of the present invention may include a receiving circuit operating on a supply voltage lower than a high-level voltage value of an input binary signal, an input level determination circuit generating an input level determination signal having a frequency higher than a frequency of the binary signal and controls whether to output the input level determination signal or not, based on a voltage level of the binary signal, and an AC coupling element connected between an output terminal of the input level determination circuit and an input terminal of the receiving circuit.
Claims10
An interface circuit, comprising:
- a connector terminal configured to receive an input signal in which one of signal levels is substantially direct current;
- an oscillating circuit configured to generate and output an input level determination signal having a frequency higher than a frequency of the input signal;
- an output control circuit having a first enable terminal connected to a first power supply node and a second enable terminal receiving the input signal via the connector terminal and an input terminal connected to the oscillating circuit to control whether to output the input level determination signal or not, based on a signal level of the input signal;
- an AC coupling element coupled to the output control circuit to transmit the input level determination signal output from the output control circuit;
- and
- a receiving circuit coupled to the AC coupling element to receive the input level determination signal, the receiving circuit comprises a clamp circuit that limits an upper limit value of the input level determination signal and includes a protective diode connected between an input node of the receiving circuit and a power supply terminal,
- wherein the oscillating circuit continues to output the input level determination signal when the output control circuit stops outputting the input level determination signal.
4 more elements
A interface circuit, comprising:
- a connector terminal configured to receive an input signal in which one of signal levels is substantially direct current;
- an oscillating circuit configured to generate and output an input level determination signal having a frequency higher than a frequency of the input signal via an output terminal;
- an output control circuit having an input terminal, and coupled to the connector terminal and the oscillating circuit to receive the input level determination signal via the input terminal and to control whether or not to output the input level determination signal, in accordance with a signal level of the input signal, to an AC coupling element which is to be coupled to the output control circuit and configured to transmit the input level determination signal a receiving circuit coupled to the AC coupling element to receive the input level determination signal to a receiving circuit comprising a clamp circuit that limits an upper limit value of the input level determination signal and includes a protective diode connected between an input node of the receiving circuit and a power supply terminal;
- another connector terminal configured to receive another input signal in which one of signal levels is substantially direct current;
- and
- another output control circuit having another input terminal, and coupled to the another connector terminal and the oscillating circuit to receive the input level determination signal via the another input terminal and control whether or not to output the input level determination signal, in accordance with a signal level of the another input signal, to another AC coupling element which is to be coupled to the another output control circuit and configured to transmit the input level determination signal,
- wherein the input terminal of the output control circuit and the another input terminal of the another output control circuit are connected electrically in parallel regarding to the output terminal of the oscillating circuit.
4 more elements
Dependencies are inferred from the claim text.