LT1510-5_15 Datasheet, PDF (1/16 Pages) Linear Technology – Constant-Voltage/ Constant-Current Battery Charger

LT1510/LT1510-5
Constant-Voltage/
Constant-Current Battery Charger
FEATURES
s _{Charges NiCd, NiMH and Lithium-Ion Batteries ––}
Only One ¹/₁₀W Resistor Is Needed to Program
Charging Current
s _{High Efficiency Current Mode PWM with 1.5A}
Internal Switch and Sense Resistor
s _{3% Typical Charging Current Accuracy}
s _{Precision 0.5% Voltage Reference for Voltage}
Mode Charging or Overvoltage Protection
s _{Current Sensing Can Be at Either Terminal of}
the Battery
s _{Low Reverse Battery Drain Current: 3µA}
s _{Charging Current Soft Start}
s _{Shutdown Control}
s _{500kHz Version Uses Small Inductor}
U
APPLICATIONS
s _{Chargers for NiCd, NiMH and Lithium Batteries}
s _{Step-Down Switching Regulator with Precision}
Adjustable Current Limit
DESCRIPTION
With switching frequency as high as 500kHz, The LT^®1510
current mode PWM battery charger is the smallest, sim-
plest, most efficient solution to fast-charge modern re-
chargeable batteries including lithium-ion (Li-Ion), nickel-
metal-hydride (NiMH)* and nickel-cadmium (NiCd)* that
require constant-current and/or constant-voltage charg-
ing. The internal switch is capable of delivering 1.5A DC
current (2A peak current). The 0.1Ω onboard current
sense resistor makes the charging current programming
very simple. One resistor (or a programming current from
a DAC) is required to set the full charging current (1.5A) to
within 5% accuracy. The LT1510 with 0.5% reference
voltage accuracy meets the critical constant-voltage charg-
ing requirement for lithium cells.
The LT1510 can charge batteries ranging from 2V to 20V.
Ground sensing of current is not required and the battery’s
negative terminal can be tied directly to ground. A saturat-
ing switch running at 200kHz (500kHz for LT1510-5) gives
high charging efficiency and small inductor size. A block-
ing diode is not required between the chip and the battery
because the chip goes into sleep mode and drains only 3µA
when the wall adaptor is unplugged. Soft start and shutdown
features are also provided. The LT1510 is available in a 16-pin
fused lead power SO package with a thermal resistance of
50°C/W, an 8-pin SO and a 16-pin PDIP.
, LTC and LT are registered trademarks of Linear Technology Corporation.
* NiCd and NiMH batteries require charge termination circuitry (not shown in Figure 1).
TYPICAL APPLICATIONS
C1
D1
0.22µF MBRM120T3
SW
V_{CC +}
D3
MBRM120T3
C_IN*
10µF
8.2V TO 20V
–+
L1**
10µH
D2
MMBD914L
BOOST PROG
LT1510-5
GND
V_C
OVP
1µF
300Ω
0.1µF
1k
6.19k
SENSE
BAT
+
+
C_OUT***
4.2V
22µF
NOTE: COMPLETE LITHIUM-ION CHARGER, NO TERMINATION REQUIRED
* TOKIN OR MARCON CERAMIC SURFACE MOUNT
** COILTRONICS TP3-100, 10µH, 2.2mm HEIGHT (0.8A CHARGING CURRENT)
COILTRONICS TP1 SERIES, 10µH, 1.8mm HEIGHT (<0.5A CHARGING CURRENT)
*** PANASONIC EEFCD1B220
† OPTIONAL, SEE APPLICATIONS INFORMATION
Q3^†
2N7002
R3
70.6k
0.25%
R4
100k
0.25%
1510 F01
Figure 1. 500kHz Smallest Li-Ion Cell Phone Charger (0.8A)
C1
D1
0.22µF 1N5819
SW
V_{CC +}
C_IN*
10µF
D3
1N5819
11V TO 28V
–+
L1**
33µH
D2
1N914
BOOST PROG
LT1510
GND
V_C
OVP
1µF
300Ω
0.1µF
1k
3.83k
SENSE
BAT
+
+
C_OUT
4.2V
22µF
TANT +
4.2V
NOTE: COMPLETE LITHIUM-ION CHARGER, NO TERMINATION REQUIRED
* TOKIN OR MARCON CERAMIC SURFACE MOUNT
** COILTRONICS CTX33-2
† _{OPTIONAL, SEE APPLICATIONS INFORMATION}
Q3^†
VN2222
R3
240k
0.25%
R4
100k
0.25%
1510 F02
Figure 2. Charging Lithium Batteries (Efficiency at 1.3A > 87%)
1