Current mirror circuit
US5703478A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 5, 1996 |
| Grant date | Dec 30, 1997 |
| Priority date | — |
| Expiry date | Apr 5, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG05F3/265
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A current mirror circuit (31) that includes an active loop which operates transistors of different conductivity type at equal base-emitter junction voltages to minimize error. A first resistor (38) couples to a base of a first transistor (32) of a first conductivity type in a voltage follower configuration. A reference current is coupled to the first resistor (38). The voltage across the first resistor (38) and base-emitter junction of the first transistor (32) is mirrored across the base-emitter junction of a second transistor (34) of a second conductivity type and a second resistor (39). A third transistor (35) of the second conductivity type in a diode configuration is coupled to receive current from the second transistor (34). The voltage across the third transistor (35) biases a fourth transistor (33) of a first conductivity type. The current from the fourth transistor (33) is provided to the first transistor such that the first and second transistors (32,34) operate at equal base-emitter voltages.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.