ip2021c International Rectifier Corp., ip2021c Datasheet - Page 8

• Manufacturer Part Number: ip2021c
• Description: Synchronous Buck Dual Channel Power Block
• Manufacturer: International Rectifier Corp.

Calculating Power Loss and SOA for Different Operating Conditions
To calculate Power Loss for a given set of operating conditions, the following procedure should be
followed:
Power Loss Procedure
To calculate the Safe Operating Area (SOA) for a given set of operating conditions, the following
procedure should be followed:
SOA Procedure
Design Example
Operating Conditions
Output Current = 50A
Switching Freq = 750 kHz
Calculating Typical Power Loss:
(Figure 1) Typical power loss = 12W
(Figure 3) Normalized power loss for input voltage  0.96
(Figure 5) Normalized power loss for output inductor  1.035
(Figure 6) Normalized power loss for switch frequency  0.93
Calculated Typical Power Loss  12W x 0.96 x 1.0 x 1.035 x 0.93  11.1W
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1. Determine the maximum current and obtain the typical power loss from Figure 1
2. Use the normalized curves to obtain power loss values that match the operating conditions in
3. The typical power loss under the application conditions is then the product of the power loss
1. Determine the maximum PCB and CASE temperature at the maximum operating current for
2. Use the normalized curves to obtain SOA temperature adjustments that match the operating
3. Then, add the sum of the SOA temperature adjustments to the T
the application
from Figure 1 and the normalized values.
each iP2021C
conditions in the application
:
Inductor = 0.2µH
Input Voltage = 10V
8/13/2009
Output Voltage = 1.3V
X
axis intercept in Figure 2
iP2021CPbF
PD-97414
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