LT3511MPMS-TRPBF データシートの表示（PDF） - Linear Technology
部品番号
コンポーネント説明
メーカー
LT3511MPMS-TRPBF Datasheet PDF : 26 Pages
| |||
LT3511
Applications Information
similar to a nonisolated buck-boost. The duty cycle will
affect the input and output currents, making it hard to
predict output power. In addition, the winding ratio can
be changed to multiply the output current at the expense
of a higher switch voltage.
The graphs in Figures 1-4 show the typical maximum output
power possible for the output voltages 3.3V, 5V, 12V and
24V. The maximum power output curve is the calculated
output power if the switch voltage is 100V during the off-
time. 50V of margin is left for leakage voltage spike. To
achieve this power level at a given input, a winding ratio
value must be calculated to stress the switch to 100V,
resulting in some odd ratio values. The following curves
are examples of common winding ratio values and the
amount of output power at given input voltages.
One design example would be a 5V output converter with
a minimum input voltage of 36V and a maximum input
voltage of 72V. A four-to-one winding ratio fits this design
example perfectly and outputs close to 1.6W at 72V but
lowers to 1W at 36V.
The equations below calculate output power:
Power = η • VIN • D • IPEAK • 0.5
Efficiency = η = ~85%
Duty Cycle = D = (VOUT + VF ) • NPS
(VOUT + VF ) • NPS + VIN
Peak switch current = IPEAK = 0.26AV
3.0
2.5
N=15 N=12
N = NPS(MAX)
N = 10
2.0
N=8
N=6
1.5
N=4
1.0
N=2
0.5
0
0
20
40
60
80
100
INPUT VOLTAGE (V)
3511 F01
Figure 1. Output Power for 3.3V Output
3.5
3.0
N=5
2.5
N = NPS(MAX)
2.0
1.5
1.0
N=4
N=3
N=2
N=1
0.5
0
0
20
40
60
80
100
INPUT VOLTAGE (V)
3511 F03
Figure 3. Output Power for 12V Output
3.0
2.5
N = NPS(MAX)
2.0
1.5
1.0
0.5
N=8
N=7
N=6
N=5
N=4
N=3
N=2
N=1
0
0
20
40
60
80
100
INPUT VOLTAGE (V)
3511 F02
Figure 2. Output Power for 5V Output
3.0
2.5 N = NPS(MAX)
N=2
2.0
N=1
1.5
1.0
0.5
0
0
20
40
60
80
100
INPUT VOLTAGE (V)
3511 F04
Figure 4. Output Power for 24V Output
3511fa
9
Share Link: 