Hobbyist Builds Mini Power Management Coprocessor on $0.15 RISC-V Microcontroller

A developer has built a power management and telemetry coprocessor for accelerator hardware using the WCH CH32V003F4U6, a low-cost RISC-V microcontroller. The firmware runs within 2 KB of SRAM, relying on static allocation, a deterministic state machine driven by a 1 ms SysTick timer, and integer-only Q15 fixed-point math. It monitors bus voltage and current through an INA219 sensor, applies exponential moving average smoothing to power readings, and sequences power rails through a state machine. Protective features include undervoltage and overvoltage lockouts, a 4.2 A overcurrent trip threshold, and an emergency shutdown interrupt. The project is shared as a demonstration of what constrained hardware can achieve in accelerator power control.