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US 4,659,979 AGranted
High voltage current source circuit and method
AssigneeBurr-Brown Corporation
InventorsStephen R. Burnham, Stephen F. Ulbrich
Life of this patent
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AssigneeBurr-Brown Corporation
InventorsStephen R. Burnham, Stephen F. Ulbrich
Estimating the term…
A high voltage constant current source circuit includes first transistor biased as a constant current source and a second transistor connected in series with the first transistor. The second transistor has a punch-through voltage that is substantially less than any breakdown voltage of the second transistor. The emitter of the second transistor is connected to the collector of the first transistor. The collector of the second transistor supplies the constant current, provides an increased high output impedance, and allows low voltage operation if the collector-to-emitter voltage of the second transistor is less than its punch-through voltage. If its punch-through voltage is exceeded, that punch-through voltage adds to the collector-to-emitter breakdown voltage of the first transistor, allowing high voltage operation.
A constant current source circuit comprising in combination:
A constant current source circuit comprising:
A method of increasing the breakdown voltage of a circuit including a first transistor, the method comprising the steps of:
Dependencies are inferred from the claim text.