How do I choose a voltage regulator?

There are three major types of voltage regulators that you will encounter in this program:

• Linear voltage regulator - burns off extra power in the form of heat
  • Advantage: High current capacity
  • Advantage: Low cost
  • Disadvantage: Low precision
  • Disadvantage: High dropout voltage (the voltage difference between the input and output)
• Low dropout voltage regulator - burns off extra power in the form of heat, but continues to regulate even when the input voltage is near the output voltage
  • Advantage: Excellent for battery-powered applications
  • Advantage: Higher precision
  • Disadvantage: Lower current capacity
  • Disadvantage: Higher cost
• Switching voltage regulator - generates as much power as is needed by the circuit, up to the maximum allowed by the regulator. Similar to Switching Power Supplies above
  • Advantage: Highly energy efficient
  • Disadvantage: High cost
  • Disadvantage: External components (some difficult to find) may be necessary
  • Disadvantage: Printed circuit board layout can be difficult
• DC-DC Converter - An Isolated power converter. (No electrical connection between input and output)
  • Advantage: Can be used on sensitive equipment that need an isolated power supply
  • Disadvantage: Requires more testing to guarantee isolation.
  • Disadvantage: External components (some difficult to find) may be necessary
  • Disadvantage: Noise due to PWM signal switching

A highly detailed guide to linear and switching regulators is available here: http://www.ti.com/lit/an/snva558/snva558.pdf

When should I use a DC-DC Converter?

A DC-DC converter should be used when the following is needed:

• Higher efficiency (95% when compared to linear voltage regulator of 65%)
• Power that can be stepped up or stepped down
• A moderate - high max voltage output.