"Masking of switching noise in controlling a ""H"" bridge"
US5886484A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 20, 1996 |
| Grant date | Mar 23, 1999 |
| Priority date | — |
| Expiry date | May 20, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02P7/04
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
Masking of switching noise is implemented in the driving system of an "H" bridge stage by exploiting the periodic signal generated by a PWM control circuit (normally present in the control system for controlling the "H" bridge in an open-loop mode) for masking the decay time of the disturbances caused by the switching from off-to-on of a first pair of switches of the bridge that drive a current in a certain direction through the load. This is implemented by keeping high for a preset period of time the periodic signal generated by the PWM circuit and varying the duty-cycle of the signal for regulating the mask time in function of the load characteristics. The system further comprises the masking of the decay interval of the disturbances caused by the switching from on-to-off of the first pair of switches and from off-to-on of the other pair of switches that provides a current ricirculation path of the energy stored in the reactance of the load, for a preset number of clock cycles, thus impeding any subsequent switching for the duration of this second mask. This second mask may be realized in different ways. The use of an up-counter and a programmable comparator is preferred.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.