6

Date: 7/1

9/06 Rev D

SP6682 High Efficiency Charge Pump Regulator for White LEDs

© 2006 Sipex Corporation

A 3-wire white LED module with internal

series resistors as shown in figure 11 can

also be driven in this way.

The current in one white LED current is set

by the ratio of the feedback pin voltage

The current of the remaining white LEDs is

set according to the similarity of the white

LEDs.

CONFIGURING THE SP6682 AS

VOLTAGE OR CURRENT SOURCE

The white LED load configuration used by

customers can be discrete white LEDs or a

white LED module. Inside the white LED

module, there may or may not be resistors

in series with the white LEDs. According

to the different application requirements, the

SP6682 can be configured as either a

voltage source or a current source to provide

solutions for these different applications, as

shown in figures 10-13.

Figure 10 shows a circuit using the SP6682

to drive discrete white LEDs as a current

source.

1

8

5

Rb

SP6682

Rb

2.2uF

GND

FB

Figure 10. Driving discrete white LEDs as current

source

3-wire W-LED module

Anode

FB

GND

Fig 11. 3-wire white LED module

GND

Anode

5

Rb

SP6682

Cathode

8

2-wire W-LED module

1

Figure 12. Driving 2-wire white LED module as current

source

In this application, the bias resistor can be

selected by:

rent of all the white LEDs.

APPLICATION INFORMATION

In Figure 12, the SP6682 was used to drive

a 2-wire white LED module without internal

series resistors as a current source. The

total current of the white LED module in-

stead of the current of single LED as in

Figure 10.