Diodes APM8600 - Manual (Page 8)

APM8600
SINGLE CELL LINEAR LITHIUM BATTERY CHARGER
WITH 28V OVP AND PROGRAMMABLE CHARGE TIMER
APM8600
Document number: DS35140 Rev. 1 - 2
8 of 14
www.diodes.com
December 2010
© Diodes Incorporated
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T
Functional Description (continued)
INPUTS
DC
Pins 12 and 13 are the DC input. This input will allow charging from input voltages between 4.15V and 7V, and can
withstand up to 28V without device damage although charging is disabled above 7.5V (typ.).
GND
System ground connection.
EN
Pin 8 is the enable pin of the device. When pulled low the device will operate normally. When high, the device will
remain in the disabled state. For auto-starting, connect pin 8 directly to GND.
SETI
Pin 2 allows the charge currents to be programmed.
ICHARGE
1500
RSETI
=
The charge current setting also changes the currents in prequal and top-off modes (being 10% and 7.5% of I
CHARGE
respectively):
RSETI
150
IPREQUAL
=
RSETI
112.5
ITOPOFF
=
This pin can also be used to monitor the battery charging current:
RSETI
1000 VSETI
ICHARGE
×
=
THM
The thermistor connection is on pin 3. This allows the battery temperature to be monitored using a 10k NTC
thermistor, which should be placed as close as possible to the battery cell. If no thermistor is used then this input should be
connected directly to ground. The charger will operate when there is less than 315
Ω on this input (i.e., no thermistor
connected); will be disabled when there is between 315 Ω and 3.94kΩ; enabled when between 3.94kΩ and 28.3kΩ; and
disabled above 28.3k Ω.
0°C 25°C 50°C Hot trip Cold Trip
3000 25.1 10 4.6 55.1 ‐3.2
3250 27.1 10 4.3 52.6 ‐1.3
3500 29.3 10 4 50.5 0.5
3750 31.7 10 3.8 48.6 2.0
Resistance in kΩ at Typical in °C Thermistor
Beta
Disable
d
Enabled
Enabled
Disable
d
0 315 Ω 3.94k 28.3k R
THM