Boost or not to boost - wide Vin boost power management ICs do much more

When the available input power is lower than the desired voltage in your system, you need a boost converter to boost (step-up) the input voltage. Examples include emergency call (eCall) systems, automotive start-stop systems, audio power amplifiers (PAs), smart grid data concentrators, thunderbolt data ports, power bank for mobile devices, tablet docking stations and many more. In these applications, input power usually comes from low voltage batteries, solar panels, or other low voltage rails, and we all know that a boost power management IC can do this job.

In some other applications, the input voltage could be either higher or lower than the output voltage, requiring a converter that can both step-down and step up. A SEPIC converter is a popular solution due to its minimal number of active devices and clamped switching waveforms. Did you know that a SEPIC converter is usually implemented using a boost power management IC? Furthermore, a boost power management IC can be configured as a flyback converter to achieve galvanic isolation for enhanced safety and improved noise immunity? Figure 1 shows some versatile configurations using the LM5001 boost IC.

Figure 1. Versatile configurations of boost power management ICs

As a power management systems engineer, I work with designers to answer their technical questions almost on a daily basis. Some frequently asked questions about boost power management ICs are:

  • How do I choose the right IC solution for a specific application?
  • How can I increase the output power capability without risking the thermal performance?
  • How can I improve the efficiency?
  • How do I extend the input voltage range?
  • How can I obtain short circuit protection for a boost converter?

To answer these questions, I recently wrote a white paper, “How to design boost, SEPIC and flyback regulators with wide VIN boost power management ICs”. In this white paper, several of TI’s wide VIN boost power management ICs are used as examples to elaborate on the following statements:

  • A converter with an integrated switch provides high integration and small total solution size, whereas a controller and external MOSFET offer more flexibility.
  • Non-synchronous solutions feature simple implementation, while synchronous solutions have lower conduction loss and higher efficiency, especially in high-current low-voltage applications.
  • Interleaving techniques can be used to increase output power capability while achieving reduced current ripple, improved efficiency, smaller passive component size and enhanced thermal performance.
  • DCR sensing can be used to eliminate discrete current sense resistors and improve efficiency, especially in high current applications.
  • A split-bias-rail configuration can extend the low input voltage range.
  • Load disconnect switch control provides true short-circuit protection for a boost converter.

Hopefully, this white paper answers some questions about the boost power management ICs, and provides some guidelines that can help you choose the most suitable product to achieve your design goal. Let me know what you think?