Bi-directional current sensing by monitoring VS voltage in a half or full bridge circuit
US7548029B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 2, 2005 |
| Grant date | Jun 16, 2009 |
| Priority date | — |
| Expiry date | Feb 11, 2027 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02M1/0009
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An apparatus and method for determining the output current in a bridge-connected switched transistor output circuit including high-side and low-side transistor switches, typically MOSFETS. The voltage at a common node between the high and low side switches is sensed, and offset in a first circuit by a fixed amount so that the voltage is positive for all positive or negative output currents of interest. The output current is actually determined in a second circuit which receives the offset voltage signal only predetermined times in relation to the on-time of the low side switch. The first circuit includes a current reference source/level shifter and a current mirror circuit formed of a plurality of transistors in a particular circuit configuration. The second circuit is coupled to an output of the first circuit by a gated NMOS transistor at the desired times to provide the current measurement signal. The second circuit includes a second current reference source having substantially the same electrical characteristics as the first current reference source, and a second plurality of transistors respectively matched to the input side circuit transistors, and connected in the same circu…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.