Monitoring of current in an inductive load, PWM driven through a bridge stage
US6061258A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 5, 1998 |
| Grant date | May 9, 2000 |
| Priority date | — |
| Expiry date | Aug 5, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02M3/1555
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
Monitoring of current flowing through an inductive load driven through a bridge power stage in a PWM mode, comprises sampling the signal output by a sensing amplifier with a Sample & Hold circuit including a sampling switch and a storing capacitor. The average value of the current in the load is monitored by sampling at a half way point of an active driving phase and at a half way point of a current recirculation phase by closing the switch with a synchronizing pulse that coincides with the half way points of these phases of operation. The monitoring uses a pair of complementary periodic reference signals and uses a sensing amplifier to amplify the signal existing on a current sensing resistor functionally connected in series with the load. This produces an amplified signal representative of the current in the load to be fed to an input of an error amplifier driving a power amplifier of the bridge stage. The synchronizing pulse is generated in coincidence with the peak and with the virtual zero crossing of the two reference periodic signals, out of phase from one another by 180 degrees. A two-input logic AND gate, combining the synchronizing pulse and a masking signal of a preestab…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.