
Preliminary Data Sheet
April 2003
PSC1534 Lithium-Ion Linear Battery Charger
Features
s
Low external component count and small footprint
s
Charge termination indication and manual shut-
down using PROG pin
s
Programmable charge current: 200 mA to 800 mA
s
4.1 V or 4.2 V preset voltages
s
Automatic trickle charging at IPROG/10 for heavily
discharged batteries requires no additional exter-
nal components
s
Very low quiescent battery current during shut-
down and standby (charger removed)
s
Charger undervoltage lockout and battery over-
voltage lockout
s
Overcurrent/overtemperature protection
s
Low-profile (1 mm) SOT-23 package
Description
The PSC1534 is a constant-current/constant-voltage
Li-Ion battery charger controller that is functionally
equivalent and performance equivalent to the
LTC1734. As an enhancement, the PSC1534 also
includes automatic detection and trickle charging of
deeply discharged batteries (VBAT <2.42 V).
The PSC1534 allows charge current programming
using a single external resistor, RPROG. The voltage
on the PROG pin is proportional to the charging cur-
rent at the ISENSE pin, allowing the user to use an
external A/D to monitor charging progress. A low bat-
tery drain (BAT pin) manual shutdown state can be
forced by floating the PROG pin. When the input sup-
ply (VIN) is removed, the PSC1534 enters a very low-
current sleep mode, during which BAT input supply
current is <1
A.
Applications
s
Any application that requires a compact, low-cost
solution for Li-Ion battery charging
Typical Application
Figure 1. 500 mA Li-Ion Battery Charger
Figure 2. PROG Pin Indicates Charge Status
VIN
5 V
VCC
3
2
RPROG
3 k
4
1
F
PROG
GND
ISENSE
DRIVE
BAT
PSC1534
1
6
5
FMMT549
IBAT = 500 mA
SINGLE
Li-Ion
BATTERY
10
F
+
10 k
To A/D
CHARGING
COMPLETE
CHARGING
BEGINS
0 V
1 V
2 V
3 V
4 V
5 V
V
PRO
G
(V
)
V
BA
T
(V)
1.5 V
CONSTANT
VOLTAGE
CONSTANT
CURRENT
VBAT
VPROG