
2-11Implantable Systems
sensor is in active mode: V
td
is the transmitted data, V
ta
is the transponder antenna voltage, V
ra
is the
sig
nal
o
f
t
he
d
ierential
v
oltage
o
f
t
he
r
eader
a
ntenna,
a
nd
V
rd
is the received data.
Ta
ble
2.2 sh
ows
th
e
po
wer
co
nsumption
du
ring
th
e
di
erent
ac
tivities
of th
e
me
asurement
sy
s-
tem,
wh
en
th
e
ex
ternal
po
wer
fr
om
th
e
re
adout
un
it
is ac
tive
. Fo
r
ex
ample,
wh
en
th
e
im
plantable
se
nsor
me
asures
an
d
tr
ansmits
th
e
da
ta
to th
e
re
adout
un
it,
th
e
mi
crocontroller
an
d
th
e
tr
ansponder
re
quire
a po
wer
su
pply
of ab
out
1.7 mW
,
wi
th
a cu
rrent
co
nsumption
of ap
proximately
85
0
μA an
d
a vo
ltage
of 2 V.
Input force
Force calculated