TY CONF TI VARIANTS OF FEEDBACK AND CONTROL LOOPS OF AC-DC CONVERTERS KW negative feedback KW optoelectronic galvanic isolation KW error signal amplifier KW PWM-controller JO CAD/EDA/SIMULATION IN MODERN ELECTRONICS 2019 AU Amelina, M.. AU Amelin, A.S. PY 2024 PB Bryansk State Technical University