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US 5,861,787 AGranted
Reverse power protection circuit and relay
OwnerRoger R. Graeberinventor
Life of this patent
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Abstract
A relay for high frequency instruments and a reverse power protection circuit for high frequency instruments are described herein. The relay is inexpensive to construct, permits good impedance matching up to approximately 5 GHz, and can be easily mounted on a coplanar waveguide transmission line. The circuit can open the relay in response to a reverse power condition in as little as 8 microseconds and provides both good grounding and functions reliably up to 4 GHz.
Claims3
A reverse power protection circuit comprising:
- a first and second reverse biased diodes coupled respectively between a signal line and a first and second AC grounding patch;
- a first and second plurality of capacitors coupled between the AC grounding patch and a first and second ground plane;
- a first and second transient absorber coupled respectively between the AC grounding patch and the ground plane;
- a resistive voltage divider network coupled to at least one of the AC grounding patches and a first comparator, the first comparator having a predefined voltage trigger threshold;
- a flip-flop circuit for providing a logic signal output when the threshold of the first comparator is exceeded;
- a first transistor coupled through an inverter to the flip-flop circuit, the first transistor acting as a switch and changing state in response to the logic signal output of the flip-flop circuit;
- a second transistor coupled to the first transistor, the second transistor acting as a switch and changing state in response to the first transistor's changing state;
- and
- a relay having an input and output, the relay being opened and closed by the de-energizing and energizing of a electromagnetic coil in the relay, the coil being de-energized when the second transistor changes state.
6 more elements
Dependencies are inferred from the claim text.