We are regaled with the wisdom of using smart power in tech pubs. It’s one of the buzz words of our day, with no one wanting to robe themselves in anything other than the green trappings of environmentally better, efficient smart power. It seems geekdom has decree pronouncing anything other than praises is sheer sacrilege. Having always believed that technology must be approached with an irreverence that breaks down barriers and builds bridges to new vistas, … here I go.
Without a doubt placing the computational power to provide power factor correction and pulse modulated passing of just the right amount of energy to the next stage in an AC/DC power supply for a server, computer or another power spiking and hunger device is indeed smart. And further downstream the same argument may be made for a point of load DC/DC stage, less the power factor correction. But as the current demand lowers so does the budget that can be allocated to a device that MIPS its way to responsive PWMing.
Lower voltage and current become the estate of state machines and other more energy efficient controllers and switching regulators. But these devices can wreak havoc in stages that deal with the processing of small signals like various sensors or wireless reception may require. Here a simple regulator may be needed to supply power and isolate from upstream noise.
I think it was about 1979 when I first tripped across the circuit for a regulator. Having used a resistor and a zener diode to regulate and also trying a regulator to regulate, I became duly impressed how much more sophisticated, dare I say ‘smart’ a regulator was. But to see the current mirrors, negative feedback to control thermal run way and the passing on of ripple, and generally the effective use of transistors to control transistors, suddenly I understood why 60 cycle seems so depressed at the output and the supply voltage so stiff. Yes, I totally geeked about how cool it was and even found fellow geeks to share the elation.
But isolation is not the only benefit a low drop out regulator or LDO can bring to the design. Having ascended the power transfer pyramid from the broad base of high power to less and less we find ourselves in an altitude of very thin current. Here too smart power finds a home if the application in question can have discontinuous operation. XLP PICmicro is famous for sleeping most of the time and thus reducing energy demand. But here too live the creatures of the dumb power domain.
In many battery applications the drop out from source to supply is so small greater efficiency can be achieved with an LDO. So while great strides in increased power efficiency can be made with smart power in many applications, there are still many applications where using so called smart power is not so smart.










