SGM3141 Datasheet, PDF (7/14 Pages) SG Micro Corp – Charge Pump LED Driver

SGM3141
TYPICAL APPLICATION
700mA Buck/Boost
Charge Pump LED Driver
The SGM3141 can be used with multiple LEDs in parallel as shown in Figure 1. For best performance, the LEDs should
be in a single package, preferably from a single die to have better matching for forward voltage V_F for a given forward
current I_F. In practice, if the V_F of one LED is higher than the others, it will consume a larger I_F, which will raise its
temperature which will then cause its V_F to decrease, correcting the imbalance. The overall current will be the sum of the
individual currents, for example I_TOTAL = 4 × I_LED.
V_IN
3.0V to 4.2V
1
2
3
Jumper
C_IN
10μF
C_F
1μF
SW2
R_EN
10kΩ
1 _VIN
VOUT ¹⁰
2 _C1
9
PGND
SGM3141
3
C2
8
SGND
4
FLASH
7
FB
C_OUT
4.7μF
5 _EN
6
RSET
R_SET
139kΩ
R_FB
0.33Ω
Figure 1. Multiple LED Flash Circuit
The SGM3141 also can be used to drive two flash LEDs in portable equipments. The schematic is shown in Figure 2.
V_IN
3.0V to 4.2V
C₁
4.7μF
C₃
1μF
FLASH
ENABLE
1 _VIN
VOUT ¹⁰
2 _C1
9
PGND
C₂
10μF
SGM3141
3
C2
8
SGND
4
FLASH
7
FB
5 _EN
6
RSET
R₃
120kΩ
D1
500mA LED
R₄
R₅
10kΩ
10kΩ
D2
500mA LED
R₁
0.22Ω
R₂
0.22Ω
Figure 2. Two Flash LED Drive
SG Micro Corp
7
www.sg-micro.com