Datasheet

( )
( )
NTC o
TCOLD
NTC o
THOT
1 1
TCOLD To
1 1
THOT To
R R e
R R e
-
-
b
=
b
=
bq51050B
bq51051B
www.ti.com SLUSB42D –JULY 2012–REVISED JANUARY 2014
Where:
T
COLD
and T
HOT
are the desired temperature thresholds in degrees Kelvin. R
o
is the nominal resistance and β is
the temperature coefficient of the NTC resistor. An example solution for part number ERT-JZEG103JA is:
R
1
= 29.402kΩ
R
3
= 14.302 kΩ
Where,
T
COLD
= 0°C
T
HOT
= 60°C
β = 4500
R
o
= 10 kΩ
The plot of the percent V
TSB
vs temperature is shown in Figure 26:
Figure 26. Example Solution for Panasonic Part # ERT-JZEG103JA
Figure 27 illustrates the periodic biasing scheme used for measuring the TS state. The TS_READ signal enables
the TS bias voltage for 25 ms. During this period the TS comparators are read (each comparator has a 10 ms
deglitch) and appropriate action is taken based on the temperature measurement. After this 25 ms period has
elapsed the TS_READ signal goes low, which causes the TS-Bias pin to become high impedance. During the
next 100 ms period the TS voltage is monitored and compared to 100 mV. If the TS voltage is greater than 100
mV then a secondary device is driving the TS/CTRL pin and a CTRL = ‘1’ is detected.
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