Datasheet

NCP3066, NCV3066
http://onsemi.com
14
Figure 23. Boost Demoboard Layout Figure 24. Boost Demonstration Photo
60
65
70
75
80
85
90
95
5 7 9 11 13 15 17 19
Figure 25. Boost LED Driver Efficiency
INPUT VOLTAGE (V)
EFFICIENCY (%)
150 mA 8 LED
(25.6 V)
150 mA 6 LED
(19.2 V)
Figure 22, Boost Demoboard Application Schematic,
illustrates the basic circuitry in boost topology, which allows
supplying string up to eight LEDs up to 150 mA
consumption. Table 3, Bill of Materials shows the small
number of additional parts which are necessary to assembly
mentioned demoboard. The demoboard based on one layer
PCB and the layout is shown in Figure 23, Buck Demoboard
Layout. The photo of this demoboard is mentioned in
Figure 24, Boost Demoboard Photo. Figure 26, Dimming
Characteristic shows behavior of circuitry in case the square
wave signal with 5 V amplitude and 300 Hz frequency was
delivered into ON/OFF pin of device. There was tested eight
LEDs string with 150 mA consumption and V
IN
= 10 V at
room temperature.
The efficiency of this demoboard is mentioned in
Figure 25. Efficiency of Boost LED Driver.
0
0.50
1.0
1.50
2.0
2.50
3.0
3.50
0 102030405060708090100
Figure 26. Dimming Characteristic
ON/OFF DUTY CYCLE (%)
LED POWER (W)
Table 4. TEST RESULTS
Line Regulation Vin = 10 V to 20 V, Vout = 19.2 V, Iout = 350 mA 25 mA
Output Ripple Vin = 10 V to 20 V, Vout = 19.2 V, Iout = 350 mA 55 mA
Efficiency Vin = 12 V, Vout = 19.2 V, Iout = 350 mA 85%