L6902D 1A Constant current battery charger
General description
The L6902D evaluation board integrates the stepdown switching regulator with adjustable current
limit L6902D as well as the external components
required for a typical application.
The input voltage of the application board can
range from 8V up to 25V due to the rated voltage
of the input capacitor and the schottky rectifier
repetitive peak reverse voltage (both 25V).
The external resistor divider (R1 and R2) sets the
output voltage of the application board to 3.3V.
A different output voltage can be regulated from
1.235V up to 10V, which is the rated voltage of the
output capacitor.
A current limit of 1A is programmed by the 100mΩ
sense resistor R
The inductor saturation current and the forward
current of the schottky rectifier fit the current limit
setting.
sense
.
EVAL6902D
evaluation board
Data Brief
Evaluation board
October 2006 Rev 1 1/4
For further information contact your local STMicroelectronics sales office.
www.st.com
4
Figure 1. Application test circuit
3
sense
C3
C
CS
EVAL6902D
D1
L1
R
V
IN
1
VCC
VREF
C4
R
L6902D
GND
OUT
+
CS-
Figure 2. Package
Table 1. Demoboard part list
Name Value P/N Manufacturer Notes
R2
V
OUT
2
C1 10
C2 100
µF C4532X5R1E106M TDK
µF 10TPB100M POSCAP
D1 STPS2L25U ST
L1 22µH DO1813HC-223 COILCRAFT
Device L6902D ST
R1 8.2 kΩ 0603, 1%
R2 3.3 kΩ 0603, 1%
R3 4.7 kΩ 0603, 1%
C3 220pF 0603, 50V
C4 22nF 0603, 50V
R
sense
100mΩ
2/4
EVAL6902D Revision history
1 Revision history
Table 2. Revision history
Date Revision Changes
17-Oct-2006 1 First issue
3/4
EVAL6902D
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