Rainbow Electronics MAX8728 - Manual (Page 8)

MAX8728
Low-Cost, Multiple-Output
Power Supply for LCD Monitors/TVs
8 _______________________________________________________________________________________
Typical Operating Characteristics
(Circuit of Figure 1. V
IN
= V
INL
= V
SUPP
= 12V, AV
DD
= 13.5V, V
GON
= 28V, V
GOFF
= -6V, V
OUT1
= 3.3V, FSEL = GND, T
A
= +25°C,
unless otherwise noted.)
STEP-DOWN REGULATOR EFFICIENCY
vs. LOAD CURRENT
LOAD CURRENT (A)
EFFICIENCY (%)
MAX8728
toc01
50
55
60
65
70
75
80
85
90
0.01 0.1 1 10
EN = GND
EN = VL
NORMALIZED STEP-DOWN REGULATOR
OUTPUT VOLTAGE vs. LOAD CURRENT
LOAD CURRENT (A)
OUTPUT VOLTAGE (V)
MAX8728 toc02
3.10
3.15
3.20
3.25
3.30
3.35
3.40
0.01 0.1 1 10
EN = GND
EN = VL
STEP-DOWN REGULATOR
LOAD TRANSIENT RESPONSE
MAX8728toc03
0V
0V
0V
LOAD CONTROL, 5V/div
LX1, 20V/div
OUT1, AC, 100mV/div
INDUCTOR CURRENT, 1A/div
4 μs/div
STEP-DOWN REGULATOR
SOFT-START (HEAVY LOAD)
MAX8728toc04
0V
0V
0V
V IN , 5V/div
OUT1, 2V/div
INDUCTOR CURRENT, 1A/div
400 μs/div
STEP-UP REGULATOR EFFICIENCY
vs. LOAD CURRENT (MEASURED AT L1/C3 JUNCTION)
LOAD CURRENT (A)
EFFICIENCY (%)
MAX8728 toc05
60
65
70
75
80
85
90
95
100
0.001 0.01 0.1 1 10
NORMALIZED STEP-UP REGULATOR
OUTPUT VOLTAGE vs. LOAD CURRENT
LOAD CURRENT (A)
OUTPUT VOLTAGE (V)
MAX8728 toc06
13.30
13.35
13.40
13.45
13.50
13.55
13.60
0.01 0.1 1 10