SUBSET SELECTION OF RFID TAGS USING LIGHT

摘要

Methods and apparatuses for selecting a subset of RFID tags are provided in some embodiments. These methods and apparatuses utilize the susceptibility to light by persistent nodes found in passive tags. Light can be used to intentionally reduce persistence times in a particular subset tags or even an individual tag. Then, persistent nodes can be used as a selection criterion to distinguish previously illuminated tags from non-illuminated tags. In other embodiments, a power circuit receives a RF input source and generates a direct current (DC) output voltage. The circuit includes a bias circuit to supply a gate to source bias, which is independent of the DC output voltage. The circuit further includes a voltage multiplier circuit that is coupled to the bias circuit. The voltage multiplier circuit has MOS transistors with one transistor to receive the gate to source bias.

主权项

1. A circuit to provide a direct current (DC) output voltage, comprising:
a first bias circuit to receive a radio frequency (RF) input; a first voltage multiplier circuit coupled to the first bias circuit, the first voltage multiplier circuit comprising a first transistor used as a rectifying element to generate the DC output voltage, the first bias circuit to generate a first bias voltage to reduce a turn on threshold voltage of the first transistor.