Typical operating characteristics (continued) – Rainbow Electronics MAX1677 User Manual
Page 6
MAX1677
Compact, High-Efficiency, Dual-Output
Step-Up and LCD Bias DC-DC Converter
6
_______________________________________________________________________________________
10mV/
div
V
LX
I
LX
V
RIPPLE
200mA/
div
100mV/
div
5
µs/div
LCD SWITCHING WAVEFORMS
MAX1677-13
LDCLX CURRENT LIMIT = 350mA,
2.4V
IN,
+12V
OUT,
10mA LOAD
10mV/
div
V
LX
I
LX
V
RIPPLE
200mA/
div
100mV/
div
2
µs/div
LCD SWITCHING WAVEFORMS
(50k
Ω FROM LCDPOL TO OUT)
MAX1677-14
LCDLX CURRENT LIMIT = 225mA,
2.4V
IN,
+12V
OUT,
10mA LOAD
50mV/
div
I
OUT
V
RIPPLE
200mA/
div
2ms/div
MAIN BOOST CONVERTER
LOAD TRANSIENT
MAX1677-15
V
IN
= 2.4V, V
OUT
= 3.3V
I
LOAD
= 0 to 200mA
2V/
div
V
LX
I
LX
V
RIPPLE
100mA/
div
50mV/
div
1
µs/div
MAIN BOOST CONVERTER SWITCHING
WAVEFORMS (PWM MODE)
MAX1677-10
2.4V
IN
, 3.3V
OUT
,
200mA I
OUT
2V/
div
V
LX
I
LX
V
RIPPLE
100mA/
div
20mV/
div
2
µs/div
MAIN BOOST CONVERTER SWITCHING
WAVEFORMS (PFM MODE)
MAX1677-11
1.2V
IN
, 3.3V
OUT
,
20mA I
OUT
2V/
div
V
LX
I
LX
V
RIPPLE
100mA/
div
50mV/
div
10
µs/div
MAIN BOOST CONVERTER SWITCHING
WAVEFORMS (PFM MODE, 50mA OUTPUT)
MAX1677-12
PFM, 1.2V
IN
,
3.3V
OUT
, 50mA I
OUT
Typical Operating Characteristics (continued)
(Circuits of Figures 2 and 3, T
A
= +25°C, unless otherwise noted.)