Isolation amplifier including precision voltage-to-duty-cycle converter and low ripple, high bandwidth charge balance demodulator
US4843339A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 28, 1987 |
| Grant date | Jun 27, 1989 |
| Priority date | — |
| Expiry date | Oct 28, 2007 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K7/08
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An isolation amplifier includes a voltage-to-duty-cycle modulator, a non-galvanic isolation barrier, and a demodulator converting a duty-cycle-modulated signal transmitted across the isolation barrier to an analog voltage replica of the analog input voltage. The modulator circuit includes a first current switching means which produces a first current that is switched between positive and negative values in response to an output from a comparator that can be referenced to a noise-synchronized signal. The first current is summed with an input current and the difference is integrated and input to the comparator, the output of which produces the duty-cycle-modulated signal. The demodulator includes a second current switching circuit for producing a second current that is switched between positive and negative levels in response to the duty-cycle-modulated signal received across the isolation barrier and includes circuitry for algebraically summing the input current with the second current and integrating the result to produce the analog output voltage. The modulator circuit and demodulator circuits are fabricated on a single semiconductor area to produce the close matching between comp…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.