SC1410A Datasheet, PDF (1/9 Pages) Semtech Corporation – Constant Voltage/Constant Current Battery Charger

SC1410A
Constant Voltage/Constant Current
Battery Charger
POWER MANAGEMENT
Description
Features
The SC1410A is designed to provide a simple, fast charg-
ing solution for rechargeable batteries that require con-
stant-current and/or constant voltage charging, including
nickel-cadmium (NiCd), nickel-metal-hydride (NiMH) and
lithium-ion (Li-Ion). With a voltage reference accuracy of
0.5% the SC1410A satisfies the tight constant-voltage
charging requirements of lithium cells.
The SC1410A simplifies battery charger design by inte-
grating a high efficiency PWM with an internal 1.5A switch
and 0.1ohm current sense resistor, while the 500kHz
switching frequency allows a very small inductor to be used.
Only one external resistor is required to program the full
1.5A charging current to within 5% accuracy.
Charging circuits for batteries ranging from 2V to 18V are
easily implemented using the SC1410A. No ground sens-
ing of current is required, allowing the battery’s negative
terminal to be connected directly to ground. No blocking
diode is required between the IC and the battery since the
SC1410A enters sleep mode and consumes only 3µA when
the AC adapter is unplugged. Other features include soft
start, overvoltage protection, and a shutdown pin. The
SC1410A is available in a 16 pin QSOP package.
‹ Charges NiCd, NiMH and Lithium-lon batteries
‹ High efficiency current mode with 1.5A internal
switch and sense resistor
‹ 3% Typical charging current accuracy
‹ Precision 0.5% voltage reference for voltage mode
charging or over voltage protection
‹ Current sensing can be either terminal of battery
‹ Low reverse battery drain current: 3µA
‹ Charging current soft start
‹ Shutdown control
‹ 500kHz switching uses small inductor
Applications
‹ Chargers for NiCd*, NiMH* and Lithium batteries
‹ Step down switching regulator with precision
adjustable current limit
*NiCd and NiMh batteries require external charge termi-
nation circuitry not contained in the SC1410A
Typical Application Circuits
Figure 1: 500kHz Li-lon cell phone charger
0.22uF
10uH
1N4148
1N5819
SW
VCC
PROG
BOOST
GND
VC
OVP
SENSE BAT
SC1410A
0.1uF
Cin
1N5819
10uF
8.2 to 18V
6.19k
1uF
Cout
+
1k _{300 22uF}
4.2V
NDS355N
70.6k
0.25%
1410 SCH41
100k
0.25%
Figure 2: Charging Lithium batteries
0.22uF
33uH
1N4148
1N5819
SW
VCC
PROG
BOOST
GND
VC
OVP
SENSE BAT
SC1410A
0.1uF
Cin
1N5819
10uF
11 to 18V
6.19k
1uF
Cout
1k _{300 22uF}
+
+^4.2V
4.2V
NDS355N
240k
0.25%
1410 SCH42
100k
0.25%
Revision: September 13, 2006
1
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