Multilevel Dual Closed-Loop Controlling Class-D Power Amplifier with FPGA

The article introduces a new switch-mode power amplifier based on a cascade multilevel topology. By adopting an advanced technology to achieve class D power amplifier multipulse PWM generator by FPGA, the amplifier enjoys a switching frequency which is 2N times of that of a single unit. The PWM trigger gathers A/D transform modulated wave by data acquiring unit, produces multi-channels phase-shifted triangle carrier waves and their reversed carrier waves by multi-channels phase-shifted triangle carrier waves control unit. The PWM trigger generates PWM trigger signals by compare control unit and deal with dead area protecting control by dead area control unit. The amplifier improves the output signal quality through dual current and voltage closed-loop control. The article lays emphasis on designing dual closed-loop control and the experiment results show that the proposed amplifier has a wide bandwidth, good instant response and high output quality.