Typical operating characteristics (continued) – Rainbow Electronics MAX8775 User Manual
Page 9
MAX8775
Dual and Combinable Graphics Core
Controller for Notebook Computers
_______________________________________________________________________________________
9
Typical Operating Characteristics (continued)
(Circuit of Figure 1, V
IN =
12V, V
DD
= V
CC
= 5V,
SKIP_ = GND, T
A =
+25°C, unless otherwise noted.)
SWITCHING WAVEFORMS
MAX8775 toc16
12V
12V
1.5V
1.2V
12V
A
B
D
E
C
0
0
D: V
OUT2
, 50mV/div
E: V
IN
, 50mV/div
A: LX1, 10V/div
B: LX2, 10V/div
C: V
OUT1
, 50mV/div
V
IN
= 12V, V
OUT1
= 1.5V, V
OUT2
= 1.2V
I
OUT1
= 5A, I
OUT2
= 5A
2
μs/div
REFIN TRANSITION WAVEFORMS
(DTRANS = V
CC
)
MAX8775 toc17
12V
1.5V
1.5V
1.2V
1.2V
10A
A
B
D
C
0
0
C: V
OUT1
, 200mV/div
D: I
LX1
, 10A/div
A: REFIN1, 500mV/div
B: LX1, 10A/div
V
IN
= 12V, V
REFIN1
= 1.2V TO 1.5V TO 1.2V
I
OUT1
= 1A
SKIP1 = GND
100
μs/div
REFIN TRANSITION WAVEFORMS
(DTRANS = GND)
MAX8775 toc18
12V
1.5V
1.5V
1.2V
1.2V
A
B
D
C
0
0
C: V
OUT1
, 200mV/div
D: I
LX1
, 10A/div
A: REFIN1, 500mV/div
B: LX1, 10A/div
V
IN
= 12V, V
REFIN1
= 1.2V TO 1.5V TO 1.2V
I
OUT1
= 1A
SKIP1 = GND
40
μs/div
COMBINED-MODE PHASE TRANSITION
MAX8775 toc19
12V
12V
1.2V
A
B
D
C
0
0
0
C: LX1, 10V/div
D: LX2, 10V/div
A: V
OUT
, 50mV/div
B: ON2, 5V/div
V
IN
= 12V, V
OUT
= 1.2V
I
OUT
= 10A
10
μs/div
COMBINED-MODE PHASE TRANSITION
MAX8775 toc20
10A
10A
1.2V
A
B
D
C
0
0
0
C: I
LX2
, 10A/div
D: I
LX1
, 10A/div
A: V
OUT
, 50mV/div
B: ON2, 5V/div
V
IN
= 12V, V
OUT
= 1.2V
I
OUT
= 10A
10
μs/div