Typical operating characteristics – Rainbow Electronics MAX1844 User Manual
Page 6
MAX1844
High-Speed Step-Down Controller with
Accurate Current Limit for Notebook Computers
6
_______________________________________________________________________________________
100
60
0.01
1
10
EFFICIENCY vs. LOAD CURRENT
70
65
75
80
85
90
95
MAX1844 toc01
LOAD CURRENT (A)
EFFICIENCY (%)
0.1
V
IN
= 7V
V
IN
= 12V
V
IN
= 20V
350
0
0.01
1
10
FREQUENCY vs. LOAD CURRENT
100
50
150
200
250
300
MAX1844 toc02
LOAD CURRENT (A)
FREQUENCY (kHz)
0.1
V
IN
= 15V, SKIP = V
CC
V
IN
= 15V, SKIP = GND
V
IN
= 7V, SKIP = GND
V
IN
= 7V, SKIP = V
CC
320
310
300
290
280
0
15
5
10
20
25
30
FREQUENCY vs. INPUT VOLTAGE
MAX1844 toc03
INPUT VOLTAGE (V)
FREQUENCY (kHz)
I
LOAD
= 1A
290
300
310
320
330
-40
-10
20
50
-25
5
35
65
80
FREQUENCY vs. TEMPERATURE
MAX1844 toc04
TEMPERATURE (
°
C)
FREQUENCY (kHz)
I
LOAD
= 1A
I
LOAD
= 4A
-40
5
20
-25 -10
35
50
65
80
CURRENT LIMIT vs. TEMPERATURE
MAX1844 toc07
TEMPERATURE (
°
C)
CURRENT LIMIT (A)
3
4
5
6
0
100
200
300
400
500
600
700
800
0
10
5
15
20
25
30
CONTINUOUS-TO-DISCONTINUOUS INDUCTOR
CURRENT vs. INPUT VOLTAGE
MAX1844 toc05
INPUT VOLTAGE (V)
LOAD CURRENT (mA)
CONTINUOUS INDUCTOR CURRENT
DISCONTINUOUS INDUCTOR CURRENT
0
1
2
3
4
5
6
7
8
0
10
5
15
20
25
30
CURRENT LIMIT vs. INPUT VOLTAGE
MAX1844 toc06
INPUT VOLTAGE (V)
CURRENT LIMIT (A)
1.8
1.6
1.4
1.2
1.0
1.0
1.4
1.2
1.6
1.8
NORMALIZED OVERVOLTAGE
TRIP THRESHOLD vs. V
OVP
MAX1844 toc08
V
OVP
(V)
NORMALIZED THRESHOLD (V/V)
OVERVOLTAGE TRIP THRESHOLD
OUTPUT VOLTAGE SET POINT
110
112
116
114
118
120
-40
10
-15
35
60
85
OVERVOLTAGE TRIP THRESHOLD
vs. TEMPERATURE
MAX1844 toc09
TEMPERATURE (
°
C)
OVERVOLTAGE TRIP THRESHOLD (%)
__________________________________________Typical Operating Characteristics
(Circuit of Figure 1, V
IN
= 15V, SKIP = GND, TON = unconnected, T
A
= +25°C, unless otherwise noted.)