Circuit and method for controlling quiescent current of an amplifier
US7262664B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 2, 2005 |
| Grant date | Aug 28, 2007 |
| Priority date | — |
| Expiry date | Aug 28, 2025 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F2203/45356
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
Typical amplifier circuits used to implement various type of power amplifiers, including line drivers, are capable of supplying high output currents while maintaining a low standby current. Variation in the manufacturing process, however, can lead to large variations in quiescent current of the amplifier. In particular, transistor mismatch and input offset voltage can cause the quiescent current to be very inconsistent from chip to chip. An amplifier in accordance with the present disclosure uses a transconductance amplifier to stabilize the quiescent current. The transconductance amplifier reduces the gain of the amplifier's input stage for very small signals such as the input offset voltage. The transconductance amplifier saturates for input signals larger than the expected offset voltage, allowing the normal high gain of the input stage to amplify the signal without significant gain reduction.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.