All publications of Junaid Aamir . जमशेदपुर , भारत

SHADES OF LOCKDOWN

In a sudden invasion

an invisible pathogen infects air sacs,

and paralyses all forms of life on the earth.

Latching on its spiky surface proteins,

behaving licentiously,

It multiplies itself, spreads in the pneumonic cavities

Of human desires and silences gossips of

Growing wheat in the languorous fields.Corpses rise, funeral processions march

Limb by limb,

Masculine traders of pine and oak offer

Free logs for funeral pyres.

Facing acute shortage of hospital beds and ventilators

Priests in white aprons sacrifice bearded

handsome alligators in balcony prayers.

In a dishonourable capitulation to the infectious droplets of death,

Prisoners are released on parole

And armies retreat in sun-burnt camps.

Exotic birds, and blood-red hibiscuses

Watch from lunatic social distance,

The growing awareness of virtue and vice.

I hear sounds of the angry silence of office goers and travellers

Locked down in their fossil homes,

Barbecuing, sailing to their fantasy destinations.

Starving vagrant labourers

Craving for a religious past

Or easing of secular isolation restrictions,

Build memorials of dead bones in their shanties.

I am told,

Nothing can be done when

Rivers flow backwards, swallowing

Their own maritime ancestors.

But it is beautiful early summer

I am not marooned of hope –

The beastly fear slowly annihilates itself

With scents of smouldering wet sandalwood, and

Life regains its glowing fire –

Stirring poem after poem

In the ancient clay pot of ashes.

Getting the Most Out of a DC/DC Converter

Modular DC/DC Converters Have Evolved for Higher Power Density

Small isolated DC/DC converter modules have been used for decades to efficiently match the supply voltage requirement of a load to the available power rail, to provide low-power auxiliary voltages such as a negative rail for an analog interface, for safety isolation or just to break ground loops for a particularly sensitive area of circuitry. As modules, through-hole single in-line pins (SIP) versions have been popular and the earliest boasted around a Watt of unregulated power output in a compact SIP-7 format, plenty enough power for many of the applications mentioned. Over the years, power density has steadily increased with unregulated 3W now available in the even smaller SIP-4 format (Figure 1)

Figure 1: Unregulated and regulated DC/DC power density increase from the 1990s (left) to today.

Fully regulated parts soon appeared, initially using a self-oscillating, variable frequency flyback circuit for minimal component count, but the latest versions are typically fixed frequency IC-based for optimum efficiency over a wider load range, giving high power density, 4:1 input range and features such as output trim and ON/OFF control. 2W in a DIP24 package was the initial benchmark, but soon SIP7 and SIP8 2W, 3W and 6W versions appeared and now the 12W benchmark has been reached (Figure 1). As power levels have increased, the modules are increasingly used for powering entire sub-systems and even whole products, rather than being used as just an auxiliary power supply. As the main power conversion stage, agency-rated isolation becomes more important and as SIP7 or SIP8 packages allow meaningful creepage and clearance between input and output pins, so a trend has been to increase power from these packages rather than to shrink module size keeping the same power.

Figure 2: Example DC/DC converter sequencing scheme.

Modular DC/DC converters have evolved significantly since their first introduction. Power density has increased dramatically but so has functionality allowing them to be used as precision power sources for modern electronic systems. The RECOM RS12-Z series is a good example, an innovative new design suitable for nominal 12, 24 or 48V DC inputs with a range of outputs delivering a full 12W at 75°C.