Isolation amplifier with precise timing of signals coupled across isolation barrier
US4835486A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 10, 1988 |
| Grant date | May 30, 1989 |
| Priority date | — |
| Expiry date | May 10, 2008 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K5/26
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A low cost, high frequency isolation amplifier includes a first voltage-to-frequency converter producing a first pair of complementary pulses in response to an analog input signal and applying them to a pair of low capacitance capacitors constituting the isolation barrier. The isolation barrier differentiates edges of the first pair of pulse signals and applies the resulting signals to inputs of a sense amplifier including a differential amplifier, a pair of comparators, and a flip-flop to precisely reconstruct the first pair of complementary pulse signals, which then are fed into a decoder circuit including a phase locked loop. The phase locked loop includes a phase detector receiving the reconstructed pair of complementary pulse signals and a second pair of complementary pulse signals produced by a second voltage-to-frequency converter. The output of the phase detector is integrated by a filter circuit, the output of which produces a voltage that represents the analog input signal and causes the output of the second voltage-to-frequency converter to be synchronized with the second pair of complementary pulse signals when the analog output signal matches the analog input signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.