Wide dynamic range transimpedance amplifier with a controlled low frequency cutoff at high optical power
US6771132B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 21, 2003 |
| Grant date | Aug 3, 2004 |
| Priority date | — |
| Expiry date | Feb 21, 2023 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03G3/3084
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A wide dynamic range transimpedance amplifier with a low cut off frequency at high optical power. An automatic transimpedance gain control and DC cancellation control feedback circuit includes variable impedance circuitry including a pnp transistor that is connected with the input signal. The impedance seen at the emitter of the pnp transistor changes according to the average value of the photodiode input current. The transconductance of the pnp transistor is not dependent on the average input current as the input current increases. The low cutoff frequency thus approaches an upper limit as the input current increases and does not increase exponentially.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.