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Overview PCB PIC Programmer Power Converter Overview Design 1 Design 2 Power Sources The Shack Tips/Techniques Vendors

Overview

The DC/DC power converter has been available for nearly twenty years. Recent designs have pushed the switching frequencies and efficiency higher. Today's devices typically operate at a switching rate of over 2.0MHz. This high frequency has allowed the use of small inductors, transformers, and capacitors. Many vendors provide a wide variety of devices. Switching regulators can increase the input voltage, decrease the voltage, or provide a constant voltage regardless of the input voltage. In addition, they can provide a constant voltage over a wide range of current levels. This makes the switching supply suitable for battery powered devices in a very low current or standby mode.

The design of a switching supply isn't all that difficult, but it does require close attention to detail and reasonable engineering practices. It isn't as easy as using a 7805 linear regulator, but the extra effort is rewarded with an efficient, cool running power supply that is ideal for battery powered hardware. For an excellent engineering introduction to switching power supplies, please review the Linear Tech application note below. This document does not contain a copyright notice and is therefore provided in its original form from this web site.

Document	Description
	Linear Tech - Application Note 19

In addition to the use of switching supplies in almost every payload and ground station design presented on this web site, two example designs of stand alone switching regulators is presented here.

Design 1 Utilizes a National Semiconductor LM3488 to provide 13VDC at 3 AMP from a nominal 8.5VDC battery. This supply was designed for a high power AM-ATV transmitter to eliminate cells from the battery pack.

Design 2 Utilizes a Linear Tech LT1613 to provide a very low noise 12VDC supply for a video modulator. This device is suitable for operation from a single Li-Ion cell or even a 1.2 NiCD cell.

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