APM8601 Datasheet, PDF (8/14 Pages) Diodes Incorporated – DUAL CHANNEL SINGLE CELL LINEAR LITHIUM BATTERY CHARGER WITH 28V

APM8601
DUAL CHANNEL SINGLE CELL LINEAR LITHIUM BATTERY
CHARGER WITH 28V OVP and PROGRAMMABLE CHARGE
TIMER
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.).
USB Pin 9 is the USB power input. This input will charge with input voltages from 4.15V to 7V. The charging current
drawn from USB is selected using the USEL pin, either at 95mA (1 USB power allocation unit) or 475mA (5 USB power
allocation units, High Power). Note that R_SETI has no effect on USB charging currents in the Charge state, but R_SETI does
affect the Prequal current when charging from USB. This pin will also withstand up to 28V, but charging is disabled above
7.5V (typ.).
If both DC and USB are connected and valid, power will be drawn from DC with charge current set by R_SETI.
USB and USEL will be ignored.
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.
RSETI = ¹⁵⁰⁰
ICHARGE
The charge current setting also changes the currents in prequal and top-off modes (being 10% and 7.5% of I_CHARGE
respectively):
IPREQUAL = ¹⁵⁰
RSETI
ITOPOFF = ^112.5
RSETI
This pin can also be used to monitor the battery charging current:
ICHARGE = ^{VSETI×1000}
RSETI
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 315Ω on this input (i.e., no thermistor
connected); will be disabled when there is between 315Ω and 3.94kΩ; enabled when between 3.94kΩ and 28.3kΩ; and
disabled above 28.3kΩ.
0
315Ω
3.94k
Enabled
R_THM
Thermistor Resistance in kΩ at
Typical in °C
Beta 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
28.3k
3750 31.7 10 3.8 48.6
2.0
APM8601
Document number: DS35138 Rev. 1 - 2
8 of 14
www.diodes.com
December 2010
© Diodes Incorporated