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How to Select IC Power Supplies

Image Credits: Allied Electronics, Newark, and ROHM Semiconductor

Integrated circuit (IC) power supplies receive an unregulated input and provide a regulated output voltage.

How IC Power Supplies Work

IC power supplies take unregulated input, change and/or regulate it to another voltage level, and output the adjusted power. Using a regulated IC power supply ensures the safety and efficient use of circuitry that requires a narrow voltage range. This video illustrates.

Video Credit: Element 14/Freescale Semiconductor

Product Specifications

Important specifications when selecting IC power supplies include,

  • Input voltage (VIN) ranges (e.g., 0.95 to 14 volts).
  • Output voltage (Volt) can be fixed (e.g., 4 or 12 VDC) or adjustable, regulated or unregulated, same or opposite polarity. Output has a tolerance (a guarantee that it will remain within a certain range).
  • Output current (Iout) ranges (e.g., 0.017 to 5 amps).
  • Quiescent (operating or ground) current (IQ) powers the regulator itself and ranges (e.g., 0.00014 to 0.85 amps).
  • The devices are designed to operate in a certain temperature range (e.g., -40 to 85 C).

For switch types, switching frequency (fsw) ranges (e.g., 112 kHz to 96 mHz), efficiency (through the duty cycle) can be at least a certain percentage (e.g., 74, 87).

Features

IC power supplies feature several main characteristics such as,

  • Shutdown (inhibit) pins disable the output.
  • Protective measures guard against reverse voltage, input overcurrent, or over heating (thermal shutdown)
  • An error flag alerts when output has dropped (generally 5%) below its nominal value.
  • One or multiple outputs exist.
  • Synchronous rectification contrasts with diode rectification.

Applications

IC power supplies are found in computing, medical, military, telecommunications, and industrial equipment; indeed, anywhere a circuit board is used.

References

Choosing the Right Power-Supply IC for your Application

Linear & Switching Voltage Regulator Handbook

Linear Voltage Regulator Fundamentals

Switching Regulator Basics