Typical operating characteristics (continued) – Rainbow Electronics MAX1554 User Manual
Page 5
MAX1553/MAX1554
High-Efficiency, 40V Step-Up
Converters for 2 to 10 White LEDs
_______________________________________________________________________________________
5
Typical Operating Characteristics (continued)
(MAX1553 driving six white LEDs, V
CC
= V
EN
= 3.6V, Circuit of Figure 1, T
A
= +25°C, unless otherwise noted.)
SWITCHING WAVEFORMS
(CONTINUOUS OPERATION,
3.75V Li+ BATTERY, 18mA OUTPUT)
MAX1553/54 toc10
2
µs/div
V
LX
V
OUT
I
L
10V/div
200mV/div
200mA/div
L1 = 47
µH, 4700pF CAPACITOR ACROSS LEDs
SWITCHING WAVEFORMS
(DISCONTINUOUS OPERATION,
3.75V Li+ BATTERY, 10mA OUTPUT)
MAX1553/54 toc11
2
µs/div
V
LX
V
OUT
I
L
10V/div
200mV/div
200mA/div
L1 = 47
µH, 4700pF CAPACITOR ACROSS LEDs
STARTUP/SHUTDOWN WAVEFORMS
MAX1553/54 toc12
40ms/div
V
EN
V
FB
V
OUT
5V/div
200mV/div
10V/div
L1 = 22
µH
BRT STEP RESPONSE
MAX1553/54 toc13
20ms/div
V
BRT
V
FB
V
OUT
1V/div
200mV/div
2V/div
L1 = 22
µH,
V
BRT
= 0.5V TO 1.25V TO O.5V