Typical operating characteristics – Rainbow Electronics MAX1698 User Manual
Page 4
MAX1698
High-Efficiency Step-Up
Current Regulator for LEDs
4
_______________________________________________________________________________________
0
5
10
15
20
25
0
4
5
2
3
1
6
7
8
9
10
MXA1698-01
V
BATT
, V
CC
(V)
OUTPUT CURRENT (mA)
OUTPUT CURRENT vs. V
BATT
AND V
CC
1 CHAIN OF 4 LEDs
vs. V
CC
vs.
V
BATT
0
0.4
0.2
0.8
0.6
1.0
1.2
0
0.6
0.8
0.2
0.4
1.0
1.2
1.4
NORMALIZED OUTPUT CURRENT
vs. ADJ VOLTAGE
MXA1698-02
ADJ VOLTAGE (V)
NORMALIZED OUTPUT CURRENT
20.0
20.5
21.5
21.0
22.0
0
4
6
8
10
2
12 14 16 18 20
MXA1698-03
INPUT VOLTAGE (V)
OUTPUT CURRENT (mA)
OUTPUT CURRENT
vs. INPUT VOLTAGE
1 CHAIN OF 4 LEDs
I
BATT
I
OUT
4 CHAINS OF 4 LEDs
0
200
100
400
300
600
500
700
900
800
1000
0
2
3
4
1
5
6
7
9
8
10
BATTERY CURRENT
vs. BATTERY VOLTAGE
MXA1698-04
V
BATT
(V)
I
OUT,
I
BATT
(mA)
0
30
20
10
50
40
90
80
70
60
100
100
400
700
1000 1300 1600 1900 2200
EXT RISE/FALL TIME vs. C
EXT
MXA1698-05
C
EXT
(pF)
RISE/FALL TIME (ns)
FALL TIME
RISE TIME
0
30
20
10
40
50
60
70
80
90
100
0
4
2
6
8
10
EFFICIENCY vs. BATTERY VOLTAGE
MXA1698-06
BATTERY VOLTAGE (V)
EFFICIENCY (%)
I
OUT
= 80mA
4 CHAINS OF 4 LEDs
0
20
10
40
30
60
50
70
90
80
100
5
25
35
15
45
55
65
75
85
MXA1698-07
OUTPUT CURRENT (mA)
EFFICIENCY (%)
EFFICIENCY vs. OUTPUT CURRENT
V
BATT
= 5V
4 CHAINS OF 4 LEDs
MXA1698-08
I
OUT
50mA/div
5ms/div
SHUTDOWN/SOFT-START TIMING
SHDN
5V/div
I
BATT
100mA/div
3.3V
0
4 CHAINS OF 4 LEDs
I
OUT
SET TO 80mA,
MXA1698-09
LED AND INDUCTOR CURRENT
WAVEFORMS
INDUCTOR
CURRENT
500mA/div
LED
CURRENT
50mA/div
1
µs/div
Typical Operating Characteristics
(Circuit of Figure 2, V
CC
= V
BATT
= 3.3V, V
ADJ
= V
REF
, T
A
= +25°C, unless otherwise noted.)