Controller for multiphase (interleaved) buck converter

Discussion in 'General Electronics Chat' started by cinsiki, Apr 5, 2012.

  1. cinsiki

    Thread Starter New Member

    Apr 5, 2012
    Hi everyone

    I have to build an interleaved buck converter. Although common practice is to apply interleaving in low voltage high current VRM applications, i am expected to build a converter with output 30-40V 20-30 A, i.e near kW ratings.

    Control chips that support interleaved channels are rare, and the ones i found are: tps40090 from TI and some similar IC's from Linear Tech. and International Rect. However, these controllers are designed for low voltage high current applications specially for synchronous buck structure.

    Here are my questions:

    1 How come a controller dictates circuit output voltage and power? Its main duty is to amplify the error signal,compare it to a ramp and produce duty cycle. Copy/paste from tps40090 datasheet: "The TPS40090/91 controllers are designed to operate in power supplies with output voltages ranging from 0.7 V to 3.3 V"

    2 Does anybody know a controller IC for a buck converter with output specs given?

    Thank you
  2. jimkeith

    Active Member

    Oct 26, 2011
    Reminds me of an off-line interleaved boost converter that I successfully simulated using multisim--this was about 12 years ago and it is all quite fuzzy now--I created a quadrature phase generator out of glue logic and did the remainder with linear. In a boost converter, interleaving makes very good sense, as the more inductors you add, the more power you get and both the input and output current waveforms approach DC.

    For buck converter topology, I cannot identify any advantages to interleaving other than current sharing--only problems--that may be why few controllers are available.
  3. cinsiki

    Thread Starter New Member

    Apr 5, 2012
    Interleaving brings many advantages: current ripple reduction for both input and output, thus voltage ripple reduction, same performance by using smaller capacitors and magnetics, increased power, increased efficiency, increased power density etc.. in return of increased system complexity and cost.

    Current trend is to use interleaved buck structure (along synchronous structure, ZVS-ZCS, or both...) to design low voltage high current converters for advancing microprocessor loads.

    However, i have to build a "rugged" converter and waiting your replies...