PROJECT TITLE :

A High-Precision CV/CC AC–DC Converter Based on Cable and Inductance Compensation Schemes

ABSTRACT:

This paper proposes a high-precision primary-facet regulation constant voltage (CV) and constant current (CC) ac-dc converter. CV output is achieved by adjusting the switching frequency and first peak voltage simultaneously, for better dynamic adjustment ability. In order to improve CV precision, a cable compensation module is adopted to inject current to pull-down resistor of auxiliary winding divider, compensating the cable voltage loss caused by the output cable resistance. On the other hand, CC output is acquired by maintaining the ratio of switching frequency and output voltage constant. The inductance compensation module regulates additional to stay the product of demagnetization time and switching frequency mounted, equalizing the inconsistent output current result from the large tolerance of the transformer primary-aspect inductance in the same batch. Moreover, an improved demagnetization time detector is proposed, that is beneficial to boost CC precision. The control chip is implemented based mostly on TSMC 0.35-μm 5-V/40-V BCD process, and a twelve V/1 A prototype has been built to prove the proposed control methodology. In CV mode, the deviation of the output voltage is at intervals ±one.5p.c, whereas that of output current is inside ±3% in CC mode.