An identification (ID) tag includes a substrate having an input capable of
receiving a high frequency signal. A first charge pump is coupled to the
input and is configured to convert the high frequency signal to a
substantially direct current (DC) voltage. A state machine is disposed on
the substrate and is responsive to a data recovered by the second charge
pump, where the state machine is capable of generating the control signal
for the back scatter switch in response to the data. The DC voltage from
the first charge pump is capable of providing a voltage supply for at
least one of the data recovery circuit, the back scatter switch, and the
state machine. The data recovery circuit includes a second charge pump
that is capable of operating on the high frequency signal simultaneously
with the first charge pump. In other words, the first charge pump can
generate the supply voltage for the ID tag from the high frequency
signal, while the second charge pump simultaneously retrieves the data
from the high frequency signal.