Power States And Current Consumption Breakdown - Elatec TWN4 MultiTech Core Manual

6 Power states and current consumption breakdown

6 Power states and current consumption
breakdown
The TWN4 Core Module supports 2 power states that can be used to reduce the current consumption of
the reader when the application calls for it.
In Normal state the reader can accommodate a request to search for a high-/low-frequency tag or interact
with peripherals on short notice; the current consumption in this state is the highest.
In Sleep state the reader is not capable of any of the above, but consumes considerably less current. The
reader can be woken by communication on USB/COM ports or a predefined timeout and taken to Normal
state.
In Stop state the reader consumes the least current and can be woken up via external/internal interrupt
and taken to Normal state.
Table 6.1 shows the expected typical current draw in the 2 states described above, depending on the
reader interface connected. It is assumed that a +5V DC Power Source is used. Results vary marginally
when +3.3V source is used in the UART-TTL option. The UART-RS232 option was exercised using
MAX3221A chip.
Table 6.1: Typical Current Consumption in Base System States (mA)
Table 6.2 shows the extra current observed when the TWN4 Core Module is integrated into a reader (these
results are to be taken as example only and are expected to change); these values are to be added to those
in the "Normal Idle" base state.
Table 6.2: Extra Current Consumption per Function added to "Normal Idle" base state (mA)
Module Version
Normal Idle
Sleep
Stop
Function
SearchTag-HF
SearchTag-LF
RS232
Speaker Constant Tone
MIFARE LEGIC
69,1 72,1
8 20
0,5 13,5
Current Consumption
+130
+25
+4
+80
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