JUN 01, 2003 revised to NOV 22, 2006

Page 7 of 14

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Q24S15050 DC-DC Converter Data Sheet

18-36 VDC Input; 5 VDC @ 15A Output

Protection Features

Input Undervoltage Lockout

Input undervoltage lockout is standard with this converter.

The converter will shut down when the input voltage drops

below a pre-determined voltage.

The input voltage must be at least 17.5 V for the converter to

turn on. Once the converter has been turned on, it will shut

off when the input voltage drops below 15 V. This feature is

beneficial in preventing deep discharging of batteries used in

telecom applications.

Output Overcurrent Protection (OCP)

The converter is protected against overcurrent or short cir-

cuit conditions. Upon sensing an overcurrent condition, the

converter will switch to constant current operation and

thereby begin to reduce output voltage. When the output

voltage drops below 2.5 Vdc, the converter will shut down

(Fig. 26).

Once the converter has shut down, it will attempt to restart

nominally every 100 ms with a 2% duty cycle (Fig 27). The

attempted restart will continue indefinitely until the overload

or short circuit conditions are removed or the output voltage

rises above 2.5 Vdc.

Output Overvoltage Protection (OVP)

The converter will shut down if the output voltage across

Vout(+) (Pin 8) and Vout(-) (Pin 4) exceeds the threshold of

the OVP circuitry. The OVP circuitry contains its own refer-

ence, independent of the output voltage regulation loop.

Once the converter has shut down, it will attempt to restart

every 100 ms until the OVP condition is removed.

Overtemperature Protection (OTP)

The converter will shut down under an overtemperature con-

dition to protect itself from overheating caused by operation

outside the thermal derating curves, or operation in abnor-

mal conditions such as system fan failure. After the con-

verter has cooled to a safe operating temperature, it will

automatically restart.

Safety Requirements

The converters meet North American and International

safety regulatory requirements per UL60950 and EN60950.

Basic Insulation is provided between input and output.

To comply with safety agencies requirements, an input line

fuse must be used external to the converter. A 10-A fuse is

recommended for use with this product.

Electromagnetic Compatibility (EMC)

EMC requirements must be met at the end-product system

level, as no specific standards dedicated to EMC character-

istics of board mounted component dc-dc converters exist.

However, Power-One tests its converters to several system

level standards, primary of which is the more stringent

EN55022, Information technology equipment - Radio distur-

bance characteristics - Limits and methods of measurement.

With the addition of a simple external filter (see application

notes), all versions of the Q24S15 converters pass the re-

quirements of Class B conducted emissions per EN55022

and FCC, and meet at a minimum, Class A radiated emis-

sions per EN 55022 and Class B per FCC Title 47CFR, Part

15-J. Please contact Power-One Applications Engineering

for details of this testing.