75 Watt, High Density, Eighth Brick DC/DC Converter

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Where:

Figure 4: TRIM Function

There is an upper limit to the trim up since the OVP level is fixed. Trimming the output voltage too high

may trigger the OVP circuit during higher load applications or during transients.

Current Limit Protection

The ASD75EB series modules include over current protection that allows them to withstand prolonged

overloads or short circuit conditions on the output without over heating. The ASD75EB series employs

hiccup mode protection such that the output shuts down during these conditions, waits for a predetermined

time (~500mS), and tries to restart. If the overload condition is still present, the converter will stop trying to

increase the output voltage and repeat the cycle.

Over Voltage Protection

The ASD75EB series modules have output over voltage protection. In the event of an over voltage

condition in the output pins, the converter will shut down immediately. Similar to hiccup mode, it

will make continuous attempts to start up until the over voltage is gone and resume normal operation

automatically

Input Under-Voltage Lockout

The ASD75EB series is designed to turn off when the input voltage is too low. This is done to avoid

stressing the input side circuitry of the primary circuit. The lockout is a comparator with hysteresis,

thus avoiding the converter jumping from on-off condition when crossing the UVLO threshold.

Trim

The Trim pin (pin 6) allows the user to adjust the output voltage across the sense pins from the initial

value. Trimming the output voltage requires the user to connect a resistor between Trim and + Vout for

output voltage trim up, or connect a resistor between Trim and – Vout for output voltage trim down. The

functions for trim up, trim down and the circuit implementation is shown in the figure 4.