Abstract
This paper presents a switched capacitor technique for bus-pumping compensation in a half-bridge class-D amplifier. The proposed approach, in addition to the almost complete reduction of the bus-pumping effect, allows the half-bridge class-D amplifier to preserve maximum energy efficiency. The studied hardware implementation of the proposed technique demonstrates its advantages of high efficiency, simple circuit, and low cost. The principal design and operating principles are analyzed and described. The experimental static characteristics and time-domain waveforms for the proposed technique are shown to verify its feasibility.
Highlights
A class-D output stage in half-bridge (HB) configuration is one of the most used output stages in general-purpose power conversion, especially when the load is in single-ended form
Apart to audio amplifiers [1,2,3,4,5,6,7], it can be found in many other applications, including power electronic converters [7,8,9,10,11], power amplifier in grid testing equipment [12,13], as a compensation amplifier in feedback systems [14,15,16,17], etc
In that case, According to Equation (8), the total power delivered by the supply is dissipated only on the load only positive current ISS contribute to power consumption, which is described as: resistance R, so the class-D amplifiers’ theoretical power efficiency is optimal
Summary
A class-D output stage in half-bridge (HB) configuration is one of the most used output stages in general-purpose power conversion, especially when the load is in single-ended form. One of the problems in HB is known as a bus-pumping (BP) effect [1,7,8,15], which, in audio applications, increases distortion and noise and degrades the sound quality It arises when the HB stage is supplied with a unilateral power source and when the amount of BP disturbance generated at power supply busses is equal to [1]:. DC power supply PS is ideal (bilateral) with output currents iSS and iDD. In that case, According to Equation (8), the total power delivered by the supply is dissipated only on the load only positive current ISS (or IDD) contribute to power consumption, which is described as: resistance R, so the class-D amplifiers’ theoretical power efficiency is optimal.
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