Datasheet

Scope Volt-meter Volt-meter Current-meter

80 Volt, 5 Amp

Power Supply

with Current

Meter

200 Watt, 60 Amp

Electrinic Load

Evaluation Board

ON/OFF

(SHUTDOWN)

OUT

Jumper

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6 Loading

WARNING

The high temperatures reached by even the most adequately rated

resistors may burn you or melt your benchtop.

An appropriate electronic load specified down to 2.0V is desirable. The resistance of a maximum load is

0.050Ω. You need thick cables! Consult a wire chart if needed. If resistor banks are used there are certain

precautions to be taken. The wattage and current ratings must be adequate for a 50A, 125W supply.

Monitor both current and voltage at all times.

7 Air Flow

Full rated power should never be attempted without providing the specified 200 CFM of air flow over the

UUT. This can be provided by a stand-alone fan.

8 Powering Up

Using the shutdown pin provided will allow powering up the source supply with the current level set low. It

is suggested that the load be kept quite nominal during the first power up. Set the current limit of the

source supply to provide about 1 1/2 times the wattage of the load. As you remove the connection from

the shutdown pin to ground, immediately check for 2.5 volts at the output.

A most common occurrence, that will prove unnerving, is when the current limit set on the source supply is

insufficient for the load. The result is similar to having the high source impedance referred to earlier. The

interaction of the source supply folding back and the UUT going into undervoltage shutdown will start an

oscillation, or chatter, that may have highly undesirable consequences.

A quick efficiency check is the best way to confirm that everything is operating properly. If something is a

miss you can be reasonably sure that it will affect the efficiency adversely. Few parameters can be

incorrect in a switching power supply without creating losses and potentially damaging heat.

Figure 2. Typical Evaluation Setup

SNVA074A–May 2004–Revised May 2013 AN-1299 LM5041 Evaluation Board

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