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When a single Buck converter outputs a large current, the increase of device stress will cause many problems such as efficiency and heat generation. In addition, in order to improve the high dynamic response, decoupling capacitors and a large number of output filter circuits are needed, which will further increase the cost and volume of the system. Therefore, a single Buck converter is generally not used in the design of low voltage and high current occasions.
It is a good solution to apply staggered parallel structure in multiphase converter. For example, if the system consists of n phases, the gate circuit is driven with a phase difference of 2π/N for every two phases.
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The advantages of staggered parallel structure are:
(1) With the same output efficiency, the staggered parallel structure does not need large inductance. ...
(2) When the switching frequency of each phase is constant, the frequency of the output voltage ripple increases with the increase of the number of phases, and the total inductance current is the sum of the inductance currents of each phase.
(3) Multiphase parallel topology reduces the current stress borne by each phase, increases the freedom of type selection, and is beneficial to the flexibility of thermal management and packaging.
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References:
1. Dewey. Modeling and Research of Multiphase Parallel Buck Converter Based on Digital Controller [D]. China University of Mining and Technology (Beijing), 20 1 1.