Protection circuit
First Claim
1. A protection circuit for a High Definition Multimedia Interface (HDMI), the protection circuit comprising:
- a pair of electrical conductors for carrying data transmitted as Transition Minimized Differential Signals,a pair of capacitors, each said capacitor having a first terminal and a second terminal, wherein the first terminal of each said capacitor is coupled to a respective one of the pair of electrical conductors,a voltage source operable to supply a DC voltage,a pair of splitters, each said splitter being coupled to a respective one of the pair of electrical conductors and arranged to split a signal from a respective one of the pair of electrical conductors between at least two signal paths, wherein one of the at least two signal paths is coupled to the voltage source, and a second of the at least two signal paths is coupled to a first terminal of a respective one of the pair of capacitors, and whereinin operation the protection circuit is arranged to couple the second terminal of each of the pair of capacitors to a cable for transmitting HDMI data, and wherein the protection circuit is operable to block a DC voltage in the cable from a High Definition Multimedia Interface source coupled to the pair of electrical conductors.
10 Assignments
0 Petitions
Accused Products
Abstract
HDMI devices coupled to interfaces in environments with high voltages, for example in an automotive vehicle, may be damaged by a short circuit between a cable and a large DC voltage. A protection circuit (100) for the high speed TMDS lines of an HDMI interface includes a DC voltage source (22, 24), a pair of capacitors (C1, C2) and a pair of splitters (12, 14). Each splitter is arranged to split a signal from respective one of the pair of electrical conductors between two signal paths, whereby one of the signal paths is coupled to the voltage source, and a second signal path is coupled to a first terminal of a respective one of the pair of capacitors. A signal received from an HDMI source (26) is split between a first path coupled to a first terminal of a respective capacitor and a second path coupled to the DC voltage source. The protection circuit can block a DC voltage on a cable (28) connected to the second terminals of the respective capacitors while providing a DC image of a receiver so allowing correct operation of a connected HDMI source.
11 Citations
20 Claims
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1. A protection circuit for a High Definition Multimedia Interface (HDMI), the protection circuit comprising:
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a pair of electrical conductors for carrying data transmitted as Transition Minimized Differential Signals, a pair of capacitors, each said capacitor having a first terminal and a second terminal, wherein the first terminal of each said capacitor is coupled to a respective one of the pair of electrical conductors, a voltage source operable to supply a DC voltage, a pair of splitters, each said splitter being coupled to a respective one of the pair of electrical conductors and arranged to split a signal from a respective one of the pair of electrical conductors between at least two signal paths, wherein one of the at least two signal paths is coupled to the voltage source, and a second of the at least two signal paths is coupled to a first terminal of a respective one of the pair of capacitors, and wherein in operation the protection circuit is arranged to couple the second terminal of each of the pair of capacitors to a cable for transmitting HDMI data, and wherein the protection circuit is operable to block a DC voltage in the cable from a High Definition Multimedia Interface source coupled to the pair of electrical conductors. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A system, comprising:
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a High Definition Multimedia Interface (HDMI) connector; a transmitter circuit having a set of outputs and configured and arranged to output a data signal in response to detecting a direct current (DC) voltage at one of the set of outputs; and a protection circuit that AC-couples (alternating current) the transmitter circuit to the HDMI connector and is configured and arranged to; transfer the data signal from the set of outputs of the transmitter circuit to the HDMI connector, block transfer of DC voltage from the HDMI connector to transmitter, thereby protecting the transmitter from high voltage on an HDMI cable connected to the HDMI connector; and provide the DC voltage from voltage source to the one of the set of outputs of the transmitter circuit, thereby prompting the transmitter circuit to transmit the data signal. - View Dependent Claims (17, 18, 19, 20)
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Specification