Global Mixed-mode Technology Inc.
EV5103-10
G5103 White LED Demo Board V1.0
Introduction
G5103 is a step-up (boost) DC/DC converter, using constant peak inductor current and minimum OFF
time PFM topology. It could output up to 16V and drive 20mA from a 2.5V ~ 5.5V input power source,
such as a Li-Ion battery. G5103 is suitable for series 2~4 white LED driver application because its
maximum 16V output capability. This solution possess high efficiency about 84% when drive 4 white
LED at 20mA output LED current with a 3.6V Li-Ion battery power input.
This demo board could demonstration:
1.
Drive 2 ~ 4 white LED @ 20mA.
2.
200Hz PWM dimming control.
3.
Only need 3.0V ~ 5.5V power source. A Li-Ion battery is a good power source.
200Hz PWM Dimming White LED Driver Demo Schematic
L1
10uH/0.5A
JP1
VCC Jumper
U2
VBAT
C3
1uF
1
2
3
IN
GND
SHDN BYP
G914C
4
C5
0.1uF
4
SHDN
FB
3
FB
U1
G5103
LED3
OUT
5
C4
1uF
+3VDC
VCC
SW
LED1
C2
0.1uF
LED2
D1
MBR0530
2 ~ 4 White LED
5
VCC
VCC
J1
1
2
3
4
BATT
VBAT
VSS
SW
1
2
C1
4.7uF
1
+3VDC U3
1
VDD
2
PWM Dim
GP5
3
GP4
4
GP3
SW1
VSS
GP0
GP1
GP2
8
7
6
5
DIM Low
SW2
DIM High
SW3
FREQ
PWM Dim
+3VDC
2
LED4
R3
240K_1%
R4
620K_1%
R2
120K_1%
VISEN
R1
27_1%
PIC12C508
18.5mA
PWM Dimming Control Introduction
SW1: Dimming dark ( minimum dimming duty = 0%)
SW2: Dimming light ( maximum dimming duty = 100%)
SW3: Change PWM dimming frequency ( 150Hz 250Hz)
Fig.1
Jan 21, 2003
TEL: 886-3-5788833
http://www.gmt.com.tw
1
GMT [ GLOBAL MIXED-MODE TECHNOLOGY INC ]
