apm8600 Diodes, Inc., apm8600 Datasheet - Page 10

• Manufacturer Part Number: apm8600
• Description: Single Cell Linear Lithium Battery Charger With 28v Ovp And Programmable Charge Timer
• Manufacturer: Diodes, Inc.

Functional Description (continued)
CHARGING PROCESS DESCRIPTION
The charging process is as follows, working through the state diagram.
The device will begin in the Disable state as the input power supply ramps from 0V. Once the input power supply has got
into the valid range (4.15V – 7V), and the device is enabled then it will enter the Prequal state. This state allows for slow
charging of a severely discharged battery. If the battery is already partially charged then the condition to move into the
Charge state is met. If it is not then the slow charge will increase the battery voltage until it can enter the Charge state, or if
the voltage does not rise sufficiently before the charge timer runs out (set using the capacitor on the CT pin) then the device
will go into the Fault state, indicating that the battery cell may be damaged or has failed and is not taking charge. In the
Prequal state the battery temperature can be monitored with a 10k NTC thermistor connected to the THM pin, and if the
battery temperature goes out of range (above ~50°C or below ~0°C, depending on thermistor choice) then charging will be
suspended with the device going into the THM state.
Once the battery has charged to a level of 3V, the device enters the Charge state, allowing faster charging of the battery in
its normal voltage range, with 10 times the current used in the Prequal state. For information on setting the charge currents,
see the functional description of the SETI pin. Again, the battery temperature is monitored and charging will be suspended if
the temperature goes out of range. The Charge state will last until the current drawn by the battery drops to 7.5% of the full
charge current. The device will then enter the Top-Off state, maintaining battery voltage and providing top-off charging
current for the time defined by the C
battery current. If the battery voltage falls below 4.05V then the device will automatically return to the Charge state.
APM8600
Document number: DS35140 Rev. 1 - 2
CHG
V
I
BAT
EN
BAT
0A
0V
150/R
I
PREQUAL
T
value. Once that timer completes, the device will enter the Done state, with zero
SETI
WITH 28V OVP AND PROGRAMMABLE CHARGE TIMER
SINGLE CELL LINEAR LITHIUM BATTERY CHARGER
1500/R
I
CHARGE
www.diodes.com
3V
SETI
10 of 14
4.2V
112.5/R
I
TOPOFF
SETI
t
APM8600
© Diodes Incorporated
December 2010