R
EM4102
Block Diagram
CLOCK
EXTRACTOR
COIL1
VDD
AC1
Logic
Clock
Cress
+
FULL WAVE
RECTIFIER
AC2
-
Csup
SEQUENCER
MEMORY
ARRAY
COIL2
VSS
Serial
Data Out
DATA
MODULATOR
DATA
ENCODER
Modulation
Control
Fig. 5
Functional Description
General
The EM4102 is supplied by means of an electromagnetic
field induced on the attached coil. The AC voltage is
rectified in order to provide a DC internal supply voltage.
When the last bit is sent, the chip will continue with the
first bit until the power goes off.
Full Wave Rectifier
The AC input induced in the external coil by an incident
magnetic field is rectified by a Graetz bridge. The bridge
will limit the internal DC voltage to avoid malfunction in
strong fields.
Clock Extractor
One of the coil terminals (COIL1) is used to generate the
master clock for the logic function. The output of the clock
extractor drives a sequencer.
Sequencer
The sequencer provides all necessary signals to address
the memory array and to encode the serial data out.
Three mask programmed encoding versions of logic are
available. These three encoding types are Manchester,
biphase and PSK. The bit rate for the first and the second
type can be 64 or 32 periods of the field frequency. For
the PSK version, the bit rate is 16.
The sequencer receives its clock from the COIL1 clock
extractor and generates every internal signal controlling
the memory and the data encoder logic.
Data Modulator
The data modulator is controlled by the signal Modulation
Control in order to induce a high current in the coil. The
coil 2 transistor drives this high current. This will affect the
magnetic field according to the data stored in the memory
array.
The EM4102 contains 64 bits divided in five groups of
information. 9 bits are used for the header, 10 row parity
bits (P0-P9), 4 column parity bits (PC0-PC3), 40 data bits
(D00-D93), and 1 stop bit set to logic 0.
1
1
1
8 version bits or
customer ID
32 data bits
1
1
1
D00 D01
D10 D11
D20 D21
D30 D31
D40 D41
D50 D51
D60 D61
D70 D71
D80 D81
D90 D91
PC0 PC1
1
D02
D12
D22
D32
D42
D52
D62
D72
D82
D92
PC2
1
D03
D13
D23
D33
D43
D53
D63
D73
D83
D93
PC3
1
P0
P1
P2
P3
P4
P5
P6
P7
P8
P9
S0
9 header bits
10 line parity
bits
4 column parity bits
The header is composed of the 9 first bits which are all
programmed to "1".
Due to the data and parity
organisation, this sequence cannot be reproduced in the
data string. The header is followed by 10 groups of 4 data
bits allowing 100 billion combinations and 1 even row
parity bit. Then, the last group consists of 4 event column
parity bits without row parity bit. S0 is a stop bit which is
written to "0"
Bits D00 to D03 and bits D10 to D13 are customer
specific identification.
These 64 bits are outputted serially in order to control the
modulator. When the 64 bits data string is outputted, the
output sequence is repeated continuously until power
goes off.
Memory Array for Manchester & Bi-Phase encoding
ICs
Copyright © 2005, EM Microelectronic-Marin SA
4
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EMMICRO [ EM MICROELECTRONIC - MARIN SA ]
