
Micrel, Inc.
Figure 6. IS Pin and V RCS (Ch1 = Switch Node, Ch2 = IS Pin, Ref1 = V CS )
Design Procedure for a LED Driver
MIC3230/1/2
Symbol
Parameter
Min
Nom
Max
Units
Input
V IN
I IN
Input Voltage
Input current
8
12
14
2
V
A
Output
LEDs
Number of LEDs
5
6
7
V F
V OUT
I LED
I PP
PWMD
OVP
Forward voltage of LED
Output voltage
LED current
Required I Ripple
PWM Dimming
Output over voltage protection
3.2
16
0.33
0
3.5
21
0.35
40
30
4.0
28
0.37
100
V
V
A
mA
%
V
System
F SW
Switching frequency
500kHz
eff
V DIODE
Efficiency
Forward drop of schottky diode
80
0.6
%
V
Table 2. Design Example Parameters
March 2011
12
M9999-030311-D