CAT4238 Datasheet, PDF (5/12 Pages) Catalyst Semiconductor – High Efficiency 10 LED Boost Converter

CAT4238
TYPICAL CHARACTERISTICS
(V_IN = 3.6 V, C_IN = 4.7 mF, C_OUT = 0.22 mF, L = 47 mH with 10 LEDs at 20 mA, T_AMB = 25°C, unless otherwise specified.)
150
2.0
VFB = 0.4 V
125
1.5
100
1.0
75
0.5
50
3.0
3.5
4.0
4.5
5.0
5.5
INPUT VOLTAGE (V)
Figure 4. Quiescent Current vs. V_IN
(Not Switching)
303
302
301
300
299
298
297
−50
0
50
100
150
TEMPERATURE (°C)
Figure 6. FB Pin Voltage vs. Temperature
0
3.0
3.5
4.0
4.5
5.0
5.5
INPUT VOLTAGE (V)
Figure 5. Quiescent Current vs. V_IN
(Switching)
310
305
300
295
10 LEDs
290
5
10
15
20
25
30
OUTPUT CURRENT (mA)
Figure 7. FB Pin Voltage vs. Output Current
1.2
SW
1.1
20V/div
Inductor
1.0
Current
100mA/div
0.9
VOUT
AC coupled
500mV/div
0.8
3.0
3.5
4.0
4.5
5.0
5.5
INPUT VOLTAGE (V)
Figure 8. Switching Frequency vs. Supply
Voltage
500 ns/div
Figure 9. Switching Waveforms
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