Abstract
Abstract Amplifiers play an important role in audio system. Class-AB amplifiers seem to be the dominative design in recent market. Compared to power efficiency, class-D amplifiers have better performance than class-AB amplifiers. It is based on the fact that class-D amplifiers use the switching operation to fully turn on or off the transistors. Class-D amplifiers have less power dissipation than class-AB amplifiers. The focus on this thesis is to develop the modulation of class-D amplifier with high power efficiency. This circuit uses TSMC 0.35 2P4M (Mixed-Signal) process to design and simulate. It includes two error amplifiers, two comparators, triangular wave generator, buffer, gate-driver, and H-bridge. All the modulation simulations are shown in this thesis, and we can obviously compare their advantages and disadvantages. If THD < 1 % is desired, then it’s better to choose the amplitude of the input signal to be within 0.7 times of the carrier wave. In fact, the power efficiency of class-D is about 85 % to 95 % generally. If we still want to increase the power efficiency, then we must make our mind to balance the power efficiency against the chip size.