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Introduction
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1 Introduction
The LM5000-3 is a monolithic IC specifically designed and optimized for flyback, boost, and SEPIC power
converter applications. It has an internal power switch rated for a maximum of 80 V, with a current limit set
to 2 A (typical). The LM5000-3 switching frequency is pin selectable for either 300 kHz (FS grounded) or
700 kHz (FS open). This EVM is designed to demonstrate a non-isolated flyback converter operating with
300 kHz of switching frequency.
Table 1 contains the electrical specifications.
Table 1. Key Electrical Specifications
EVM Input Voltage Range Output Voltage Output Current Range
LM5000EVAL 20 V to 55 V 3.3 V 0 A to 2 A
2 Test Setup
2.1 Connectors and Test Points Description
Table 2 shows the I/O connectors and test points included in this EVM. A power supply capable of
supplying at least 1 A must be connected to input connectors IN and GND1. The load must be connected
to output connectors OUT and GND2. The maximum load current capability must be at least 2 A. Test
point SD provides a connection to monitor shutdown control signal with GND1 as the ground reference.
Table 2. Connectors and Test Points
Reference Description
Designator
IN Input voltage connection and test point
GND1 Input voltage return connection and test point
OUT Output voltage connection and test point
GND2 Output voltage return connection and test point
SD Shutdown control input pin test point
2.2 Quick Setup Procedure
The following steps provide the quick setup procedures:
Step 1. Set the power supply current limit to 1 A. Turn off the power supply. Connect the positive
output of the power supply to IN and the negative output to GND1.
Step 2. Connect the load to OUT for the positive connection and GND2 for the negative connection.
Step 3. Set the power supply voltage to 20 V and the load to 0.1 A. The electronic load voltage
should be in regulation with a nominal 3.3-V output.
Step 4. Slowly increase the load while monitoring the output voltage between OUT and GND2. It
should remain in regulation with a nominal 3.3-V output as the load is increased up to 2 A.
Step 5. Slowly sweep the input voltage from 20 V to 55 V. The output voltage should remain in
regulation with a nominal 3.3-V output.
Step 6. Turn off the load, and decrease the input voltage down to 0 V to shut down the flyback
converter, and then turn on the load to discharge the output capacitors.
2 LM5000EVAL Non-Isolated Flyback Evaluation Module User’s Guide SNVU452 – July 2014
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