EUP8010X
Functional Description
Temperature Qualification ( 8010A,8010D Only)
The EUP8010X continuously monitors battery
temperature by measuring the voltage between the TS
and VSS pins.
An internal current source provides the bias for most
common 10-kΩ negative-temperature coefficient
thermistors (NTC) (see Figure 4). The device compares
the voltage on the TS pin against the internal V
(LTF)
and
V
(HTF)
thresholds to determine if charging is allowed.
Once a temperature outside the V
(LTF)
and V
(HTF)
thresholds is detected the device immediately suspend the
charge. The device suspend charge by turning off the
power FET and holding the timer value (i.e. timers are
NOT reset). Charge is resumed when the temperature
returns to the normal range.
However the user may modify these thresholds by adding
two external resistors. See Figure 5.
Battery Pre-Conditioning
During a charge cycle if the battery voltage is below the
V
(LOWV)
threshold, the EUP8010X applies a precharge
current, I
O(PRECHG)
, to the battery. This feature revives
deeply discharged cells. The resistor connected between
the ISET and V
SS
, R
SET
, determines the precharge rate.
The V
(PRECHG)
and K
(SET)
parameters are specified in the
specifications table.
I
O(PRECHG)
=
V(PRECGH )
×
K (SET )
R SET
Figure 5. Temperature Sensing Thresholds
Battery Charge Current
The EUP8010X offers on-chip current regulation with
programmable set point. The resistor connected between
the ISET and V
SS
, R
SET
, determines the AC charge rate.
The V
(SET)
and K
(SET)
parameters are specified in the
specifications table.
V(SET )
×
K (SET )
I
O(OUT)
=
R SET
----------------------
(2)
------------
(1)
The EUP8010X activates a safety timer, t
(PRECHG)
, during
the conditioning phase. If V
(LOWV)
threshold is not
reached within the timer period, the EUP8010X turns off
the charger and enunciates FAULT on the STATx pins.
Please refer to the Timer Fault Recovery section for
additional details.
Battery Voltage Regulation
The voltage regulation feedback is through the OUT pin.
This input is tied directly to the positive side of the
battery pack. The EUP8010X monitors the battery pack
voltage between the OUT and VSS pins. When the
battery voltage rises to V
O(REG)
threshold, the voltage
regulation phase begins and the charging current begins
to taper down.
As a safety backup, the EUP8010X also monitors the
charge time in the charge mode. If charge is not
terminated within this time period, t
(CHG)
, the EUP8010X
turns off the charger and enunciates FAULT on the
STATx pins. Please refer to the Timer Fault Recovery
section for additional details.
Figure 4. Temperature Sensing Configuration
DS8010X Ver 1.2 June 2007
9
EUTECH [ EUTECH MICROELECTRONICS INC ]
