Input current compensation during current measurement
US9977057B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 16, 2015 |
| Grant date | May 22, 2018 |
| Priority date | — |
| Expiry date | Aug 26, 2035 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02M1/0009
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A current measurement circuit may include unbuffered inputs, and the current may be sampled directly from the input pins. The input current created from each sample may be cancelled by injecting opposite charge on the subsequent sample. This direct sampling from the pins increases the common mode input range of the sense path without having to build high linearity rail-to-rail input buffers, hence lowering cost and power consumption of the current measurement path. It also allows for high-impedance input sampling. The measurement circuit may include multiple sampling stages, with a first sampling stage implemented as a switched-capacitor based circuit. A compensator circuit coupled in a feedback loop from the output of the first sampling stage to the input pins may be operated to provide the equivalent charge back to the input pins every cycle to cancel the input current required to charge the sampling capacitors of the first sampling stage.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.