ST EVAL6902D User Manual
EVAL6902D
L6902D 1A Constant current battery charger evaluation board
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 Rsense.
The inductor saturation current and the forward current of the schottky rectifier fit the current limit setting.
Data Brief
Evaluation board
October 2006 |
Rev 1 |
1/4 |
For further information contact your local STMicroelectronics sales office. |
www.st.com |
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EVAL6902D
Figure 1. Application test circuit
VIN |
VCC |
OUT |
L1 |
Rsense |
VOUT |
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VREF |
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D1 |
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CS+ |
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R1 |
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COMP |
L6902D |
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CS- |
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C1 |
C4 |
FB |
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C2 |
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C3 |
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R3 |
GND |
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R2 |
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Figure 2. Package
Table 1. |
Demoboard part list |
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Name |
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Value |
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P/N |
Manufacturer |
Notes |
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C1 |
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10 F |
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C4532X5R1E106M |
TDK |
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C2 |
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100 F |
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10TPB100M |
POSCAP |
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D1 |
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STPS2L25U |
ST |
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L1 |
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22 H |
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DO1813HC-223 |
COILCRAFT |
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Device |
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L6902D |
ST |
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R1 |
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8.2 kΩ |
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0603, 1% |
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R2 |
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3.3 kΩ |
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0603, 1% |
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R3 |
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4.7 kΩ |
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0603, 1% |
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C3 |
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220pF |
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0603, 50V |
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C4 |
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22nF |
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0603, 50V |
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Rsense |
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100mΩ |
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2/4
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