Quick Start Manual For Linear Technology
Demo board DC370A-A (4.1V) and DC370A-B (4.2V)
LTC1734 Linear Battery Charger for One Li-Ion Cell at 4.1V or 4.2V
Demonstration board DC370A is a constant-current/constant-
voltage battery charger designed to charge one Lithium-Ion cell. This
demoboard features a preset charge voltage (±1%) where the charge
current can be easily programmed and monitored allowing for easy
interface with a CPU or other circuitry providing charge termination.
The LTC1734 used on this demoboard drives an inexpensive PNP
transistor in a linear regulator configuration that provides up to
700mA of charge current. The IC and the pass transistor are
available in tiny 5 and 6-pin SOT 23 packages which reduces the
total circuit area to less than 0.08 square inches, although additional
pc-board copper area is needed for heat dissipation.
Other Features include; Preset float voltages of 4.1 & 4.2V ±1%
700mA Constant Current (can be programmed for other charge
currents ranging from 100mA to 700mA)
Monitor charge current using the Program pin
No isolation diode required
No sense resistor required
Manual Shutdown
Low battery drain current when input supply is removed
Typical Demo Board Specifications
Input Voltage Range (V
IN
) 4.7V to 7V (upper range limited by pc board
dissipation) Output Voltage (V
BAT
) in constant voltage
mode 4.1 ±1% for DC370A-A and 4.2V ±1% for
DC370A-B Output Current (I
BAT
) in constant
current mode 700mA ±10%
Program pin voltage at full charge current
1.5V ± 5% Battery
Drain Current with V
IN
Removed <1µA
Test Equipment Required for Demo Board Evaluation
Lab Power supply for input power 0 to 7V @ 1A
Digital voltmeter for measuring input voltage (V
IN)
3-1/2 digits
Digital voltmeter for measuring battery voltage (V
BAT)
4-1/2 digits, resolution to 1mV
Digital voltmeter for measuring program pin voltage 3-1/2 digits, resolution to 1mV
Digital voltmeter for measuring voltage across 3-1/2 digits
current sense resistor
Li-Ion cell or *Battery Simulator 4.1 or 4.2V Rechargeable Li-Ion
Cell
*Battery Simulator consists of;
Power supply with coarse and fine 0 to 5V @2A
output voltage adjust controls
1
