User's Manual

9
To reduce power, the module duty cycles its transmitter. The duty cycling
happens according to the read commands that the application executes. To achieve the
lowest power, after all tags are read, the transmitter turns off. After a period of time, the
transmitter activates to identify new tags in the field. After all new tags are read, the
transmitter turns off for the rest of the period.
Also, the module automatically reduces the power out if the input voltage is too low
or the temperature of the module is too high.
Reader Power States
There are four different power states for the RFID module.
Reader Power States and Levels of Consumption
Off 0 (3.3 V turned off to the module)
Deep Sleep • 3.3 V on
•
RF enable = Off
•
< 1 mA
•
Real Time Clock (RTC) = On (< 100 μA to power RTC)*
•
Enable (Pin 20) is low
Idle • 3.3 V on
•
RF enable = On
•
No USB activity
•
About 35 mA
•
Enable (Pin 20) is high
Read Max current during tag read about 1.5 A
*You cannot turn off the RTC unless you remove power Pin 2 (VBATT)
on the mini-PCI connector.
Power State Level of Consumption