ISL9301 Intersil Corporation, ISL9301 Datasheet - Page 6

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ISL9301

Manufacturer Part Number
ISL9301
Description
High Input Voltage Charger
Manufacturer
Intersil Corporation
Datasheet
www.datasheet4u.com
Typical Application Circuit
Theory of Operation
When a valid input voltage is applied at VIN, the ISL9301
first regulates VOUT at 4.5V for system power need. In the
mean time, if the battery is attached, the ISL9301 also
charges the battery while supplying current to the system.
When the system exceeds the maximum available current,
either limited by the IC or by the input power supply, the
charger FET is operated in a reverse mode, i.e. it discharges
current to the system instead of charging.
The charger function is similar to other Li-ion battery
chargers, i.e. it charges the battery at a constant current
(CC) or a constant voltage (CV) depending on the battery
terminal voltage. The constant current I
external resistor R
Circuit” on page 6. The constant voltage is fixed at 4.2V. If
the battery voltage is below a typical 2.8V trickle charge
threshold, the ISL9301 charges the battery with a trickle
current (~16% of the programmed constant current) until the
battery voltage rises above the trickle charge threshold.
When the battery voltage reaches the final voltage of 4.2V,
R
IREF
INPUT
R
IMIN
IREF
R
, as shown in the “Typical Application
R
C
TIME
1
3
6
VIN
IREF
IMIN
TIME
GND
R
D
REF
R
R
PART
R
1
1
TIME
C
C
C3
R
IREF
IMIN
, R
, D
1
2
3
is set with the
2
2
ISL9301
10µF X5R ceramic cap
1µF X5R ceramic cap
1Ω, 5% resistor
26.7kΩ, 1%, for 150mA charge current
137kΩ, 1%, for 23mA EOC current
1MΩ, 1% resistor for 75µs clock period
470Ω, 5% resistor
LEDs for indication
4.7µF X5R ceramic cap
BATON
VOUT
VBAT
CHG
PPR
ISL9301
PRESS AND HOLD 2s TO TURN ON
DESCRIPTION
the charger enters the CV mode and regulates the battery
voltage at 4.2V to fully charge the battery without the risk of
overcharging. Upon reaching an end-of-charge (EOC)
current, the charger indicates the charge completion with the
CHG pin, but the charger continues to deliver 4.2V at the
VBAT pin until the timeout limit has reached. Figure 1 shows
the typical charge profile with the EOC/reset events.
The EOC current level IMIN is programmable with the
external resistor R
the trickle charge starts and rises to HIGH at an EOC event.
After the EOC is reached, the CHG status is latched at HI.
The CHG status will be reset to logic LO when the VBAT
voltage drops to below the recharge threshold (4.05V), as
shown in Figure 1.
A thermal foldback function reduces the charge current
anytime when the die temperature reaches typically +115°C.
This function guarantees safe operation when the
printed-circuit board (PCB) is not capable of dissipating the
heat generated by the linear charger.
D
R
1
1
R
D
2
2
IMIN
C
. The CHG signal turns to LO when
2
TO μP
TO SYS
C
3
BATT
February 25, 2008
FN6435.0

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