LT3782(RevF) 查看數據表（PDF） - Linear Technology

零件编号

产品描述 (功能)

比赛名单

LT3782
(Rev.:RevF)

2-Phase Step-UP DC/DC Controller

Linear Technology 

LT3782

APPLICATIONS INFORMATION

2. Power MOSFET switching and conduction losses:





IO(MAX)

2



PFET

=





1–

2

DMAX





• RDS(ON) • DMAX •
T

IO(MAX)

+k

•

VO2

•

2

1– DMAX

• CRSS

•

f

3. The I2R losses in the sense resistor can be calculated

almost by inspection.

PR(SENSE)

=







IO(MAX)

2

1– DMAX

2







•

R

•

DMAX

4. The losses in the inductor are simply the DC input cur-

rent squared times the winding resistance. Expressing

this loss as a function of the output current yields:



IO(MAX)

2



PR(

WINDING)

=





1–

2

DMAX





•RW

5. Losses in the boost diode. The power dissipation in the

boost diode is:

PDIODE

=

IO(MAX )

2

•

VD

The boost diode can be a major source of power loss

in a boost converter. For 13.2V input, 42V output at 3A,

a Schottky diode with a 0.4V forward voltage would

dissipate 600mW, which represents about 1% of the

input power. Diode losses can become significant at

low output voltages where the forward voltage is a

significant percentage of the output voltage.

6. Other losses, including CIN and CO ESR dissipation and

inductor core losses, generally account for less than

2% of the total losses.

PCB Layout Considerations

To achieve best performance from an LT3782 circuit, the

PC board layout must be carefully done. For lower power

applications, a two-layer PC board is sufficient. However,

at higher power levels, a multiplayer PC board is recom-

mended. Using a solid ground plane under the circuit is

the easiest way to ensure that switching noise does not

affect the operation.

In order to help dissipate the power from MOSFETs and

diodes, keep the ground plane on the layers closest to the

layers where power components are mounted. Use power

planes for MOSFETs and diodes in order to improve the

spreading of the heat from these components into the

PCB.

3782ff

15

Share Link: