Powersolve PMQ7250 Series - Manual (Page 6)

Powersolve Electronics Ltd. 8A Arnhem Road, Newbury, RG14 5RU. England
Tel: 01635 521858 Fax: 01635 523771 Email: [email protected]
www.powersolve.co.uk
DC-DC Switching Regulator
Mechanical Specification
Recommended Hole Pattern
Recommended Hole Pattern for R suffix
All dimensions in inches (mm)
Standard Straight Pin Version
Optional Right Angle Pin Version (R suffix)
Technical Notes
Input Fusing
The PMQ7250 Series is not internally fused . Certain applications and safety agencies may require the installations of
fuses at the inputs of power conversion products. When selecting the fuse it must be one that is greater than the
maximum input current of the module, which occurs at the minimum input voltage. We would recommend a slow blow
fuse rating of 8A to take into consideration worse case scenarios.
Safety Considerations
The PMQ7250 Series are non-isolated DC-DC converters and as such must be installed with compliance with relevent
safety agency specifications (usually UL/IEC/EN60950). In particular for a non isolated converter’s output voltage to
meet SELV requirements, it’s input must also be SELV compliant.
Remote Sense
Modules with suffix “S” offer a positive output sense function. The sense function allows local regulation for overcoming
moderate IR drops in conductors and/or cabling. The sense lines carry very little current and therefore require a
minimal cross sectional area conductor. As such, it is not a low impedance point and must be treated with care in
layout and cabling. Sense line should be run adjacent to signals, preferably ground. If the remote sense is not needed
the sense pin should be left open or connected to Vout directly. Use of trim and sense functions can cause the output
voltage to increase, thereby increasing output power beyond the specified rating. It is therefore inportant to ensure that
Vout (at pins) x Iout doesn’t exceed output power rating.
Output Over Voltage Protection
The PMQ7250 does not incorporate this feature. If the output load requires protection against over voltage, then
voltage limiting circuitry would need to be added externally.
Output Over Current Protection
The PMQ7250 incorporates over current and short circuit protection. If the load current exceeds the internal over
current setpoint, the module will immediately turn off and goes into hiccup mode. The unit has auto recovery once the
short circuit or overload is removed. The typical average output current during hiccup mode is less than 4A max.
As with most converters of this type it is possible to operate in a condition that is between the rated output current and
over current setpoint. Be careful never to operate continuously in this heavy overload condition as this can cause
permenant damage to the module
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