SP6682 Datasheet, PDF (9/12 Pages) Sipex Corporation – High Efficiency Charge Pump Regulator for White LEDs

Where V_i, I_i are input voltage and current V_F, I_F
are the forward voltage and operating current of
White LEDs I_Q is quiescent current, which is
considered small compared with I_F.
n is the boost ratio (X1.5 or X2)
SP6682 High Voltage White LED Driver
The SP6682 can also be configured as a high
voltage boost converter to drive more than 10
white LEDs. Figure 15 shows the schematic of
APPLICATION INFORMATION
this application as well as actual data showing
efficiency of > 85%. By using an external induc-
tor, MOSFET and diode, high output voltage
can be generated to drive 12 white LEDs (2
branches, each branch has 6 white LEDs in
series). The current through the white LEDs is
determined by:
I_LED
=
V_FB
R₁
Vin: 2.7-4.2V
C1
10uF
X5R Ceramic
EN/PWM
L1 LQH32CN4R7M11
4.7uH
DS SCHOTTKY MBR0530 ILED = VFB/R1 = 20mA
D1
D7
SP6682
1
2
3
4
5
R3
1M
V_OUT
C1P
V_IN
V_MODE
FB
C2P ¹⁰
9
C1N
GND ⁸
7
C2N
EN/PWM ⁶
D2
D8
D3
D9
2.2uF 25V
C3 X5R
Q1
Ceramic
SI1304
D4
D10
SOT23
25V
D5
D11
D6
D12
R1
R2
15
15
Figure 15. Using SP6682 as a High Voltage White LED Driver
100
95
90
85
80
75
70
2.7 3.0 3.3 3.6 3.9 4.2
V_IN (V)
PINOUTS
VOUT ₁
C1P ₂
VIN ₃
VMODE ₄
FB ₅
10 C2P
SP6682
10 Pin DFN
9 _C1N
8 _GND
7 _C2N
6 _EN/PWM
V_OUT 1
C1P 2
V_IN 3
V_MODE 4
FB 5
SP6682
10 Pin MSOP
10 C2P
9 _C1N
8 _GND
7 _C2N
6 _EN/PWM
Date: 5/5/04
SP6682 High Efficiency Charge Pump Regulator for White LEDs
9
© Copyright 2004 Sipex Corporation