Variable gain amplifier and variable gain amplifier module
US7391260B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 25, 2006 |
| Grant date | Jun 24, 2008 |
| Priority date | — |
| Expiry date | Oct 12, 2026 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F2203/45524
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An analog variable gain amplifier (VGA) adjusting a signal level of a mobile communication system is provided. More particularly, design of a VGA using an operational transconductance amplifier (OTA) having a wide linear input/output range is disclosed. The VGA includes two double-differential-pair OTAs and feedback resistors. A first differential input of a first double differential pair OTA receives an input signal from the forward stage, and a second differential input is negatively fed back through a differential output and a passive resistor. An input in which a first block of the connection structure and first and second differential inputs of a second double differential pair OTA are connected receives an output signal of the first block stage. The output is negatively fed back in series through a variable resistor whose resistance varies exponentially with an adjustment voltage from outside. According to the VGA, it is possible to provide a characteristic of linear variation of gain on a logarithmic scale with respect to a control voltage with a simple and inexpensive constitution. In addition, the VGA can be designed for a low pass filter having a conventional OTA used for…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.