2 vlim trip – Kontron MARS Smart Battery Kit User Manual
Page 15
MARS User´s Guide
h
R169 Æ 5,5 V
(recommendable at e.g 2S2P LiIon Smart Batteries)
h
R170 Æ 8,2 V
(recommendable at e.g 3S3P LiIon Smart Batteries)
h
R171 Æ 11,0 V
(recommendable at e.g 4S3P LiIon Smart Batteries)
h
Another resistor at the voltage devider at R189 can be used optionally to select a
different threshold voltage. Following formula calculates R189 and 0Ω resistor at R172
activates this special threshold voltage
Ω
⋅
−
=
k
300
V
19
,
1
U
V
19
,
1
189
R
Trip
h
Without any jumper resistor and without R167 the threshold voltage is deactivated.
Additionally the LOPWR Pin of the LTC1760 should be connected to VCC.
5.1.2 VLIM TRIP
The maximum charging voltage is also controlable by jumper resistors. (Charger Output Voltage
Limit).
The value of an external resistor connected from the VLIMIT pin to GND determines one of five
voltage limits that are applied to the charger output value. See Table below. These limits provide a
measure of safety with a hardware restriction on charging voltage, which cannot be overridden by
software. This voltage sets the limit that will be applied to the battery as reported by battery. Since
the battery internal voltage monitor point is the actual cell voltage, you may see higher voltages,
up to 512mV higher, at the external charger terminals due to the voltage servo loop action. (See
Operations section 3.6 in the datasheet of the LTC1760 for more information on the voltage servo
system.)
Selectable thresholds for the charging voltage:
0Ω-Jumper bei
V
MAX
R173
Up to 8,4V
R174
Up to 12,6V
R175
Up to 16,8V
R175
Optional
The optional value can be e. g. 21V if R190 = 100kΩ.
(for more information see datasheet of the LTC1760)
Smart Battery System Manager
14