DPA423 Power Integrations, Inc., DPA423 Datasheet - Page 17

• Manufacturer Part Number: DPA423
• Description: Highly Integrated DC-DC Converter Ics For Distributed Power Architecturesthe Dpa-switch ic Family Introduces a Highly Integratedsolution For DC-DC Conversion Applications in The 16-75 Vdcinput Range.dpa-switch Uses The Same Proven Topology as Topswit
• Manufacturer: Power Integrations, Inc.

resistors R8 and R9 and is fed to the low voltage 1.24 V
reference U3. Feedback compensation is provided by R6, R7
and C11 together with C4 and R4. Capacitor C10 provides a
soft-finish characteristic, preventing output overshoot during
start-up.
Key Application Considerations
DPA-Switch Design Considerations
Power Table
This section provides a description of the assumptions used to
generate the power tables (Tables 1 and 3 through 6) and
explains how to use the information provided by them.
All Power tables: Tables 1 and 3 through 6
• Maximum output power is limited by the device internal
• Data assumes adequate heat sinking to keep the junction
• The use of P and G packages are recommended for device
Forward power tables: Tables 1 (upper half), 3 and 4
• Output power figures are based on forward topology using
• Dissipation data assumes a diode loss representing 6% of the
Flyback power tables: Tables 1 (lower half), 5 and 6
• Output power and dissipation figures are based on a 5 V
• Device dissipations above 1.5 W are possible using the
The power tables provide two types of information. The first is
the expected device dissipation for a given output power. The
second is the maximum power output. Each table specifies the
input voltage range and assumes a single 5 V output using
Schottky diode rectification.
current limit. This is the peak output power which could
become the continuous output power, provided adequate
heat sinking is used.
temperature at or below 100 °C and worst case R
T
dissipation equal to or less than 1.5 W only due to package
thermal limitation. For device dissipation above 1.5 W, use
R package.
Schottky diode rectification. Up to 5% higher output power
is possible using synchronous rectification.
total output power and combined loss in magnetic components
representing 6% of the total output power. DPA-Switch
losses are based on a ratio between conduction and switching
losses of approximately 3:1. These assumptions are typical
for a single 5 V output forward converter design using
Schottky rectification and adequately designed magnetic
components.
output using Schottky diode rectification with an efficiency
of 85%. Values are generated by calculation based on
I
correlated to bench measurement of each DPA-Switch device.
R package. However the forward converter topology is
recommended for such higher power designs.
2 •
J
= 100 °C.
R
DS(ON)
losses and characterization of switching losses,
DS(ON)
at
For example, referring to Table 1, for 36-75 VDC input range,
DPA424 would typically dissipate 1 W in a 23 W forward
converter and has a maximum power capacity of 35 W. In the
same converter, DPA425 would dissipate 0.5 W. Selecting
DPA425 with associated reduced dissipation would increase
overall converter efficiency by approximately 2%.
Issues Affecting Dissipation:
1) Using synchronous rectification will tend to reduce device
Table 4. Output Power Table for 24 VDC Minimum Input Voltage
Table 5. Flyback Output Power Table for 16 VDC Minimum Input
Table 3. Output Power Table for 16 VDC Minimum Input Voltage.
Notes: 1. Maximum output power is limited by device internal
current limit. 2. See text in this section for a complete description of
assumptions. 3. See Part Ordering Information.
Total Device
Total Device
PRODUCT
PRODUCT
Total Device
PRODUCT
Dissipation
Dissipation 0.5 W 1 W
Dissipation 0.5 W 1 W
dissipation.
DPA423
DPA424
DPA425
DPA423
DPA424
DPA425
DPA426
DPA423
DPA424
DPA425
DPA426
(See Table 3 for Notes).
Voltage (See Table 3 for Notes).
3
3
OUTPUT POWER TABLE
3
OUTPUT POWER TABLE
OUTPUT POWER TABLE
16-32 VDC RANGE (FORWARD)
24-48 VDC RANGE (FORWARD)
16-32 VDC RANGE (FLYBACK)
10 W 14 W 22 W 27 W
12 W 16.5 W 25 W 31 W 37 W 43 W
11 W 16 W 23.5 W
16 W 22 W 35 W 43 W
18 W 25 W 39 W 48 W 58 W 65 W
5 W
7 W 10 W 15 W
8 W 11 W
6.5 W
0.5 W
5 W
7 W
7 W
0.75 W
8.5 W 10 W
10 W 12 W
-
2.5 W 4 W
2.5 W
-
-
1 W
-
DPA423-426
4 W
-
-
-
-
15 W
1.5 W
6 W
2
-
-
2
6 W
2
-
-
-
-
4/04
15.5 W
Output
L
Output
Output
11.5 W
Power
7.5 W
31 W
Power
Power
11 W
22 W
25 W
47 W
Max
6 W
Max
Max
17
1
1
1