Seema N Varma

US Patent:

54444462, Aug 22, 1995

Filed:

Jul 1, 1993

Appl. No.:

8/087822

Inventors:

Venugopal Gopinathan - Dallas TX
Seema Varma - New York NY

Assignee:

Texas Instruments Incorporated - Dallas TX

International Classification:

H03M 110

US Classification:

341135

Abstract:

A current duplicator (10) is provided for receiving a calibration current and providing an output current to a load (10). Current duplicator (10) includes a transconductor (14) having a differentially coupled input with a parasitic capacitance for storing a differential voltage during a supply period. This parasitic capacitance also converts a difference current into the voltage during a feedback period. The difference current is equal to the difference between the output current and the calibration current. Transconductor (14) converts the voltage into the output current. The current duplicator also includes a first switch network for coupling the output current to the load (12) during the supply period. The output current remains within a predetermined amount from the calibration current during the supply period. A second switch network feeds back the difference current to the input during the feedback period at least until the output current becomes substantially equal to the calibration current.