Texas Instruments Evaluation Board for the LM5020 LM5020EVAL/NOPB LM5020EVAL/NOPB Datenbogen
Produktcode
LM5020EVAL/NOPB
COMPENSATION
30V - 75V
V
CC
RT
SS
OUT
CS
V
IN
UVLO
COMP
FB
LM5020
Simplified Flyback Converter
V
OUT
V+
Powering and Loading Considerations
Figure 1. Simplified Flyback Converter
3
Powering and Loading Considerations
When applying power to the LM5020 evaluation board certain precautions should be followed. The
LM5020 evaluation board is quite forgiving of load and input power variations. The possibility of shipping
damage or infant failure is always a concern at first power-up.
LM5020 evaluation board is quite forgiving of load and input power variations. The possibility of shipping
damage or infant failure is always a concern at first power-up.
4
Proper Connections
Be sure to choose the correct wire size when attaching the source supply and the load. Monitor the
current into and out of the UUT. Monitor the voltages in and out directly at the terminals of the UUT. The
voltage drop across the connecting wires will yield inaccurate measurements. For accurate efficiency
measurements, these precautions are especially important.
current into and out of the UUT. Monitor the voltages in and out directly at the terminals of the UUT. The
voltage drop across the connecting wires will yield inaccurate measurements. For accurate efficiency
measurements, these precautions are especially important.
5
Source Power
At low input line voltage (30V) the input current will be approximately 0.63A, while at high input line
voltage the input current will be approximately 0.23. Therefore to fully test the LM5020 evaluation board a
DC power supply capable of at least 75V and 1A is required. The power supply must have adjustments for
both voltage and current. An accurate readout of output current is desirable since the current is not subject
to loss in the cables as voltage is.
voltage the input current will be approximately 0.23. Therefore to fully test the LM5020 evaluation board a
DC power supply capable of at least 75V and 1A is required. The power supply must have adjustments for
both voltage and current. An accurate readout of output current is desirable since the current is not subject
to loss in the cables as voltage is.
The power supply and cabling must present a low impedance to the UUT. Insufficient cabling or a high
impedance power supply will cause droop during power supply application with the UUT inrush current. If
large enough, this droop will cause a chattering condition upon power up. This chattering condition is an
interaction with the UUT undervoltage lockout, the cabling impedance and the inrush current.
impedance power supply will cause droop during power supply application with the UUT inrush current. If
large enough, this droop will cause a chattering condition upon power up. This chattering condition is an
interaction with the UUT undervoltage lockout, the cabling impedance and the inrush current.
6
Loading
An appropriate electronic load specified for operation down to 2.0V is desirable. The maximum load
current is specified as 4.5A. Minimum load is specified at 5% or 0.23A. The resistance of a maximum load
is 0.73
current is specified as 4.5A. Minimum load is specified at 5% or 0.23A. The resistance of a maximum load
is 0.73
Ω
(including cables). The resistance of a minimum load is 14.4
Ω
.
2
AN-1314 LM5020 Evaluation Board
SNVA082B – March 2004 – Revised May 2013
Copyright © 2004–2013, Texas Instruments Incorporated