3

POWER SUPPLY DATA

For a 4x15mA White LEDs application, in which the output current is 60mA, the power supply

data is provided as Fig 1 to Fig 3. The white LEDs used here were from LUMEX (Part Number

SML-LX2832UWC-TR). Figure 1 shows the input and output voltage ripple when the input

voltage is 3.9V (SP6683 is in X1 mode), Figure 2 shows the input and output voltage ripple

when the input voltage is 3.3V (SP6683 is in X1.5 mode). Figure 3 shows the typical efficiency

curve in the input voltage range. Channel 1 is the input ripple and the channel 2 is the output

ripple. Other applications, such as 80mA output current application (4 20mA white LEDs in

parallel), have the similar characteristic.

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

100.0

2.7

3.0

3.3

3.6

3.9

4.2

Vin (V)

Figure 3. Efficiency vs Input Voltage

Figure 1. X1 Mode Voltage Ripple @ 3.9V

Figure 2. X1.5 Mode Voltage Ripple @ 3.3V