High-Precision and High-Resolution DC Standard Source Design Based on Multi-Channel PWM Method

High-precision DC voltage standard sources can be used for calibrating measuring instruments., and generating high-precision signals in various high-tech fields. The main challenge of the standard sources lies meeting the high requirement for precision and resolution, which has become the focus of research in this field. In this paper, methods to improve accuracy and the resolution of the DC standard source are studied, and a programmable high-precision and high-resolution DC voltage standard source is proposed. By employing the automatic calibration algorithm and negative feedback circuit proposed in the paper, a high precision DC voltage output of 12 ppm is achieved. A coordinated modulation scheme is presented, utilizing multi-channel PWM signals with varying amplitudes, to enable voltage amplitude adjustment and improve the resolution of the output voltage to be higher than
$0.05\mu \mathrm{V}$
‘, The proposed standard source has been successfully applied to the self-developed standard source prototype.