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US 11,605,947 B2Granted
Intrinsically safe circuit with low leakage current
AssigneeABB Schweiz AG
InventorWilfredo Fernando Baluja
Life of this patent
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Abstract
According to an aspect of this disclosure, an intrinsically safe circuit includes a voltage source, a Zener diode, a transistor, a switching element, one or more resistors, and a current limiting stage. According to this aspect, the intrinsically safe circuit may be configured such that an over-voltage threshold is determined by a voltage across the Zener diode, a base-emitter voltage of the transistor, and a voltage across the one or more resistors.
Claims20
An intrinsically safe circuit comprising:
- a Zener diode, a first transistor, a switching element, one or more resistors, and a current limiting stage, wherein an over-voltage threshold is determined by a voltage across the Zener diode, a base-emitter voltage of the transistor, and a voltage across the one or more resistors.
A system comprising:
- a voltage source,
- a load, and
- an intrinsically safe circuit comprising a voltage clamping circuit and a current limiting circuit, wherein the intrinsically safe circuit is configured to accept an input voltage from the voltage source and to maintain a leakage current of less than 10 μA while the input voltage is less than a maximum safe voltage.
A method of operating an intrinsically safe field transmitter, the method comprising:
- coupling a voltage supply to an intrinsically safe circuit;
- coupling an intrinsically safe field transmitter to the intrinsically safe circuit;
- and
- powering the intrinsically safe field transmitter by the voltage supply via the intrinsically safe circuit, wherein the intrinsically safe circuit has a voltage drop less than 2 volts between an input voltage received from the voltage supply and an output voltage delivered to the intrinsically safe field transmitter.
1 more element
Dependencies are inferred from the claim text.