LTC3859_15 Datasheet, PDF (8/42 Pages) Linear Technology – Low IQ, Triple Output, Buck/Buck/Boost Synchronous Controller

LTC3859
TYPICAL PERFORMANCE CHARACTERISTICS
Efficiency and Power Loss
vs Output Current (Boost)
100
10000
90
80
1000
70
60
100
50
40
30
20
10
0
0.0001 0.001 0.01
CCM EFFICIENCY
PULSE-SKIPPING 10
EFFICIENCY
BURST LOSS
BURST
EFFICIENCY
1
CCM LOSS
PULSE-SKIPPING
LOSS
0.1
0.1
1
10
OUTPUT CURRENT (A)
FIGURE 12 CIRCUIT
V_IN = 5V, V_OUT = 10V, V_BIAS = V_IN
3859 G10
Load Step (Boost)
Burst Mode Operation
Efficiency
vs Output Current (Boost)
100
V_IN = 8V
90
V_IN = 5V
80
70
60
50
40
30
20 _{FIGURE 12 CIRCUIT}
10 VBIAS = VIN
0 ^{VOUT = 10V}
0.0001 0.001 0.01 0.1
1
OUTPUT CURRENT (A)
10
3859 G11
Efficiency vs Input Voltage (Boost)
100
FIGURE 12 CIRCUIT
99 V_BIAS = V_IN
98
V_OUT = 10V
I_LOAD = 2A
97
96
95
94
93
92
91
90
2 3 4 5 6 7 8 9 10
INPUT VOLTAGE (V)
3859 G12
Load Step (Boost)
Pulse-Skipping Mode
Load Step (Boost)
Forced Continuous Mode
V_OUT
100mV/
DIV
AC-
COUPLED
V_OUT
100mV/DIV
AC-COUPLED
V_OUT
100mV/DIV
AC-COUPLED
I_L
5A/DIV
I_L
5A/DIV
I_L
5A/DIV
200μs/DIV
V_OUT = 10V
V_IN = 5V
FIGURE 12 CIRCUIT
3859 G13
200μs/DIV
V_OUT = 10V
V_IN = 5V
FIGURE 12 CIRCUIT
3859 G14
200μs/DIV
V_OUT = 10V
V_IN = 5V
FIGURE 12 CIRCUIT
3859 G15
Inductor Current at Light Load
(Boost)
Soft Start-Up (Boost)
FORCED
CONTINUOUS
MODE
Burst Mode
OPERATION
5A/DIV
PULSE-
SKIPPING
MODE
2μs/DIV
V_OUT = 10V
V_IN = 7V
I_LOAD = 1mA
FIGURE 12 CIRCUIT
V_OUT3
2V/DIV
GND
3859 G16
2ms/DIV
V_IN = 5V
FIGURE 12 CIRCUIT
8
3859 G17
Boost Regulated Feedback
Voltage vs Temperature
1.212
1.209
1.206
1.203
1.200
1.197
1.194
1.191
1.188
–45 –20
5 30 55 80
TEMPERATURE (°C)
105 130
3859 G18
3859fa