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ATS-SERIES

The ATS Series converters utilize a single-ended

forward topology with resonant reset. The nominal

switching frequency is 500KHz. Electrical isolation

and tight output regulation are achieved through the

use of a magnetically coupled feedback. Voltage

feed-forward with duty factor limiting provides high

line rejection and protection against output over

voltage in the event of an internal control loop failure.

This mechanism limits the maximum output voltage

to approximately 20% over the nominal regardless

of the line voltage.

Circuit Description

An internal EMI filter allows the converter to meet

the conducted emissions requirements of MIL-STD-

461C on the input power leads. A single-stage output

filter reduces the typical output ripple to less than

50mV peak-to-peak. Output current is limited under

any load fault condition to approximately 125% of

rated.

An overload condition causes the converter output

to behave like a constant current source with the

output voltage dropping below nominal. The

converter will resume normal operation when the

load current is reduced below the current limit point.

This protects the converter from both overload and

short circuit conditions. The current limit point

exhibits a slightly negative temperature coefficient

to reduce the possibility of thermal runaway.

An external inhibit port is provided to control

converter operation. The converter’s operation is

inhibited when this pin is pulled low. It is designed

to be driven by an open collector logic device. The

pin may be left open for normal operation and has a

nominal open circuit voltage of 10.5V with respect

to the input return (pin 2). The output voltage of all

models can be adjusted using a single external

resistor.