Texas Instruments Evaluation Board for the LM5039 LM5039EVAL/NOPB LM5039EVAL/NOPB 데이터 시트
제품 코드
LM5039EVAL/NOPB
LM5039 Evaluation Board
National Semiconductor
Application Note 2025
Ajay Hari
February 17, 2010
Application Note 2025
Ajay Hari
February 17, 2010
Introduction
The LM5039 evaluation board is designed to provide the de-
sign engineer with a fully functional power converter based
on the half-bridge topology to evaluate the LM5039 controller.
The evaluation board is provided in an industry standard
quarter brick footprint. The performance of the evaluation
board is as follows:
•
sign engineer with a fully functional power converter based
on the half-bridge topology to evaluate the LM5039 controller.
The evaluation board is provided in an industry standard
quarter brick footprint. The performance of the evaluation
board is as follows:
•
Input Operating Range: 36V to 75V
•
Output Voltage: 3.3V
•
Measured Efficiency: 89% @ 30A, 92% @ 15A
•
Frequency of Operation: 400 kHz
•
Board Size: 2.28 x 1.45x 0.5 inches
•
Load Regulation: 0.2%
•
Line Regulation 0.1%
•
Line UVLO (31V/30V on/off)
•
Constant Current Limit
The printed circuit board consists of 6 layers, 2 ounce copper
outer layers, and 3 ounce copper inner layers on FR4 mate-
rial, with a total thickness of 0.062 inches. The unit is designed
for continuous operation at rated load at <40°C and a mini-
mum airflow of 200 CFM.
outer layers, and 3 ounce copper inner layers on FR4 mate-
rial, with a total thickness of 0.062 inches. The unit is designed
for continuous operation at rated load at <40°C and a mini-
mum airflow of 200 CFM.
Theory of Operation
Power converters based on the half-bridge topology offer
high-efficiency and good power handling capability up to
500W. A simplified half bridge circuit is illustrated below. The
capacitors C1 and C2, which form one-half of the bridge, are
arranged in series such that the mid-point is at half the input
voltage. The other half of the bridge is formed by the switches
Q1 and Q2. Switches Q1 and Q2 are turned on alternatively
with a pulse-width determined by the input and output volt-
ages and the transformer turns ratio. Each switch, when
turned on, applies one-half the input voltage to the primary of
the transformer. The resulting secondary voltage is then rec-
tified and filtered with an LC filter to provide a smoothened
output voltage. In half-bridge topology, the primary switches
are turned on alternatively energizing the windings in such a
way that the flux swings back and forth in the first and the third
quadrants of the B-H curve. The use of two quadrants allows
better utilization of the core resulting in a smaller core volume
compared to the single-ended topologies such as a forward
converter.
high-efficiency and good power handling capability up to
500W. A simplified half bridge circuit is illustrated below. The
capacitors C1 and C2, which form one-half of the bridge, are
arranged in series such that the mid-point is at half the input
voltage. The other half of the bridge is formed by the switches
Q1 and Q2. Switches Q1 and Q2 are turned on alternatively
with a pulse-width determined by the input and output volt-
ages and the transformer turns ratio. Each switch, when
turned on, applies one-half the input voltage to the primary of
the transformer. The resulting secondary voltage is then rec-
tified and filtered with an LC filter to provide a smoothened
output voltage. In half-bridge topology, the primary switches
are turned on alternatively energizing the windings in such a
way that the flux swings back and forth in the first and the third
quadrants of the B-H curve. The use of two quadrants allows
better utilization of the core resulting in a smaller core volume
compared to the single-ended topologies such as a forward
converter.
30112701
Simplified Half-Bridge Circuit
© 2010 National Semiconductor Corporation
301127
www.national.com
LM5039 Evaluation Board
AN-2025