Multiphase Buck Converter

A multiphase buck converter is several buck (step-down) converter stages wired in parallel and switched out of phase with each other to feed a single, demanding load. Modern CPU, GPU, and mining-ASIC core supplies routinely use 6 to 12 phases to deliver well over 100A at a low core voltage while staying above 90% efficiency. The voltage regulator module (VRM) on a hashboard or GPU is almost always a multiphase buck.

Why interleave the phases

Each phase carries only a fraction of the total current, so its inductor and switches run cooler and can be smaller. By shifting each phase in time, the converter staggers when each one is delivering its current ripple. The ripples partially cancel at the shared output, which dramatically reduces the net output voltage ripple and shrinks the output capacitance needed. Splitting the load across phases also spreads the heat, improving thermal management and reliability over a single oversized stage.

Why miners and builders care

An ASIC core may need hundreds of amps at well under a volt; no single buck stage handles that cleanly. Multiphase design is what makes that delivery practical, and it is also why a failing VRM phase is a common board-level fault: one dead phase forces the survivors to overheat. Each phase typically uses synchronous rectification to keep conduction loss low at these currents.

The core regulation in each leg relies on synchronous rectification, and the whole stage sits downstream of the supply's PFC and DC-DC conversion chain.