Patent ID: 8571596

Claim:
A method of power negotiation between a first contactless device and a second contactless device, said second contactless device providing an electromagnetic field which is set to a first power level, said first contactless device using the electromagnetic field as an energy source, wherein said method comprises the steps of: a) sending a request from the first device to the second device, said request targeting a second power level and a duration; b) sending, to the first device, a response, corresponding to the request, said response (i) reflecting a decision of the second device by indicating acceptance or rejection of said request, and (ii) including, at least when indicating acceptance of said request, power capabilities of the second device that define the minimum and maximum power levels which may be provided by the second device; and c) if the decision indicates acceptance of said request, and subsequent to sending the response to the second device, switching the electromagnetic field to said second power level.