Voltage Domain

A voltage domain is a group of hashing ASIC chips on a mining hashboard that are wired in series and share a single regulated voltage rail. Modern Antminer-class boards do not power each chip independently; instead they divide the chips into domains, and a dedicated buck converter delivers one precisely regulated voltage to each domain. This is the single most important fact to grasp before attempting board-level repair, because it determines how voltage is measured, controlled and diagnosed.

Series wiring and per-domain control

Because the chips in a domain are connected in series (the output of one feeds the next), the board supplies a higher voltage to the domain and each chip drops a fraction of it. A typical hashboard splits its chips into several domains, and the firmware can adjust voltage per domain to balance the board — but it cannot tune a single chip in isolation. This is why correct firmware documentation speaks of per-domain voltage control, and why the common claim of "per-chip voltage control" is wrong: voltage is a domain-level quantity. (Frequency, by contrast, is adjustable per chip.)

Why domains matter for diagnostics

Domains are the natural unit of fault-finding. When one chip in a series-connected domain fails open or short, it collapses or unbalances the voltage across that entire domain, dropping the board's hashrate even though most chips are healthy. A technician localizes the fault by measuring each domain's voltage in turn against the board's expected per-domain reference, narrowing a dead board down to the failing domain, then to the failing chip or its buck converter. This domain-by-domain voltage walk is the backbone of hashboard repair.

Voltage domains are powered by a buck converter per domain and diagnosed against the per-domain figures in D-Central's diode & voltage reference; firmware autotuning sets voltage per domain while tuning frequency per chip.