Pulse power controls has launched switch mode power supply. All electronic equipments nowadays are having either ac/dc power supply or ac/dc converter. The basic technology has advanced from linear power supplies to switch mode power supplies [smps] which are not only smaller and lighter but also much more efficient than their linear counter part. The switching power supplies are generally offline devices. They directly rectify and filter the ac line voltage without first using 50/60 hz transformer. Then the filtered dc is chopped by a power switch and high frequency transformer and is finally rectified and filtered again. The transformer and capacitor are much smaller and are 60 to 80% more efficient. The smps generally uses linear post-regulator to improve output regulation. The output ripple is generally in the range of 25 to 100 mv peak to peak, which is higher than that of linear supply. The rms value of this ripple is much lower. The smps has the advantage of wider input voltage range and a much longer hold up time and there is little effect of input voltage range on efficiency, ie, ±50%, making it useful under brown out conditions.
