Diodes APM8601 - Manual (Page 8)

APM8601
DUAL CHANNEL SINGLE CELL LINEAR LITHIUM BATTERY
CHARGER WITH 28V OVP and PROGRAMMABLE CHARGE
TIMER
APM8601
Document number: DS35138 Rev. 1 - 2
8 of 14
www.diodes.com
December 2010
© Diodes Incorporated
NEW PROD
UC
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.).
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.
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