AG32VF407 DC Current Acquisition Instrument

This project develops a wide-range DC current acquisition instrument for current sampling. It uses an AG32 VF407 as the main controller with a built-in FPGA, and an AD7606 for 200kHz synchronous sampling. A precision operational amplifier is used for signal amplification. For
the power supply section,
since it will be used with a USB interface connected to a computer, and the USB interface voltage is usually below 5V and fluctuates, affecting the precision operational amplifier, a boost-then-buck approach is adopted.
First, a DC-DC converter boosts the voltage to approximately 6.6V, then a TPS7A4701RGWR precision power supply is used to convert it to 5.0V. This power supply is specifically designed to power the precision operational amplifier and has very low noise. Currently, there are two hardware solutions for the
front-end
amplification. The analog front-end uses an INA186A5IDCKR and an RS8554 precision operational amplifier. Actual testing shows that the two solutions perform almost identically.
The RS8554 is configured as a differential amplifier, with a 2.5V reference signal superimposed on the non-inverting input. This ensures a 2.5V output when there is no current, a maximum output of 5V, and a minimum output of 0V.
Range
switching is achieved using a high-speed voltage comparator and FPGA, currently implemented via I/O interrupts in the software, with a switching time of 2.4µs. This speed is imperceptible to the load, as the load power supply typically has filter capacitors; µF-level capacitors are sufficient to support the 2.4µs switching time. 
AD sampling
is performed using an AD7606, which simultaneously provides a 2.5V reference voltage to the op-amp. The system achieves sampling of positive and negative currents from 1µA to 10A with
resolutions below 1µA in the 400µA range, below 1mA in the 400mA range, and below 20mA in the 10A range . The main control unit uses an AGM32VF407VGT6 microcontroller with a built-in 2K FPGA. Furthermore, the positions of any digital I/O pins can be interchanged, greatly simplifying wiring. Currently, it's developed using a pure MCU; later, utilizing the on-chip FPGA for ADC sampling and level switching will result in extremely fast speeds. Enthusiasts are welcome to join group 691864140 to learn and exchange ideas together!