Miscellaneous active electrical nonlinear devices – circuits – and – Specific identifiable device – circuit – or system – With specific source of supply or bias voltage
Reexamination Certificate
2007-05-22
2009-10-06
Donovan, Lincoln (Department: 2816)
Miscellaneous active electrical nonlinear devices, circuits, and
Specific identifiable device, circuit, or system
With specific source of supply or bias voltage
C323S316000
Reexamination Certificate
active
07598800
ABSTRACT:
The present invention uses two transistors instead of a sensing resistor to provide a constant current source for a load such as an array of light emitting diodes (“LEDs”). In the present invention, a bias current is applied to a branch of the circuit. The drain-to-source voltages of two transistors are matched. The voltage at the gate of both transistors is controlled based on the bias current and the drain-to-source current of the first of the two transistors. The second of the two transistors is sized such that source current of the second transistor is a multiple of the source current of the first transistor for a given gate voltage. By the techniques of this invention, the load current in a circuit is efficiently kept constant at a multiple of the input bias current.
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International Search Report for PCT/US08/64271, mailed Aug. 22, 2008.
S Dilip
Santo Hendrik
Thandi Gurjit S.
Vi Kien
Donovan Lincoln
Hiltunen Thomas J
mSilica Inc
Turocy & Watson LLP
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