9
August ’01
Chapter 1. Product Description
Typically the device is supplied by a 3 V Lithium-battery. A built-in voltage regulator allows
a battery charge of appropriate battery types or a battery back-up function.
In back-up function it is possible to transmit data back to the base station via one of the low
frequency channels without using the UHF Transmitter. This mode is less power consuming
compared to an UHF transmission but requires a charge-up of a charge capacitor during an
extended wake period.
All three antennas can receive energy from the base station and supply the internal circuits of
the device with energy derived from the magnetic field at the antenna coils. The antenna volt-
ages of the different antennas can reach a very high level due to induced voltage. To avoid
damage of the integrated circuit, the inputs RF and VCL, are protected by Voltage Limiter
circuits.
The transmission back to the base station is using the TIRIS HDX FSK modulation and the
telegrams can therefore be made compatible to current battery-less TIRIS transponder sys-
tems. For this purpose a simple two-wire interface to the Microcomputer can be used.
A complete Identification Device consists of the following parts:
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External components
Antenna 1 (LR1)
Resonant Circuit Capacitor 1 (CR1)
Antenna 2 (LR2)
Resonant Circuit Capacitor 1 (CR2)
Antenna 3 (LR3)
Resonant Circuit Capacitor 3 (CR3)
Charge Capacitor (CL)
Battery
Buffering Capacitor (Cbat)
Battery Backup De-coupling Diode (Dbat), if function is desired
VCCO Jumper (J1), if Battery Backup or Battery Charge is desired
Microcomputer
UHF Transmitter
Test/ Trimming Interface Connector
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3D-Analog Front End IC TMS37122