Method for automatic compensation of the loading effect for high-precision buffer amplifiers

To reduce errors due to loading effects, an automatic compensation circuit (ACC) for the loading effect is developed. The concept of the ACC is quite simple. The ACC generates a current in relation to the difference between the input and load voltages. The ACC compensates for the errors automatically with only a connection to the buffer amplifier in parallel. The errors due to loading effects were compensated to nearly zero with the ACC. Furthermore, to confirm the function of the ACC, we used an inductive voltage divider (IVD) that has known load characteristics. The errors of the in-phase components reach 1 × 10^-4 owing to loading effects, but the errors are compensated to nearly zero with the ACC. Similarly, the errors of the quadrature components are compensated by the ACC automatically.