Battery powered high efficiency single‐stage switching amplifier

Abstract

A high efficiency single-stage switching amplifier based on high-frequency link inverter is proposed. Bipolar phase shift modulation is adopted in the proposed switching amplifier. Auxiliary circuits including freewheeling diodes, clamp capacitors and active clamp bridge (ACB) are added to provide a current flowing path for the inductor current during the dead time of the bidirectional switches. The ACB is synchronised with primary-side switches to absorb the leakage inductor energy and clamp the secondary-side transformer voltages. With single-stage conversion and leakage inductor energy recycle, high efficiency of the proposed switching amplifier is achieved. A 5 V/25 W prototype is presented to verify the analysis results of the proposed switching amplifier.

Soft‐switching single‐stage three‐level power amplifier for high‐voltage audio distribution systems

“…An active capacitive voltage clamp [3] composed of diode uncontrollable rectifier and auxiliary flyback converter can provide an alternative load current flowing path and solve commutation problem. However, the stored energy in the leakage inductor of main and auxiliary transformers leads to severe voltage spikes, which, aside from creating electromagnetic‐interference problems [4], and usually drives MOSFETs into avalanche mode. In addition, SICAM soft‐switching conditions are highly dependent on both load current and output voltage resulting in switches partially operating in zero voltage switching (ZVS) across different output power range [3].…”

“…Introduction: High-power Class D switching amplifiers have gained popularity for high-voltage ('100-volt line') audio distribution systems commonly used in stadiums, convention centres and anywhere multiple loudspeakers and long cable runs are required [1,2]. However, a switching-mode isolated DC-DC power supply (SMPS) is necessitated to provide sufficient DC bus voltage for powering Class D power amplifiers [3,4], which increases product volume and reduces overall system efficiency. To simplify design and increase efficiency, a single conversion stage amplifier (SICAM) [3] representing an ultimate integration of SMPS and Class D power amplifiers into one compact direct converter has been presented.…”

“…To simplify design and increase efficiency, a single conversion stage amplifier (SICAM) [3] representing an ultimate integration of SMPS and Class D power amplifiers into one compact direct converter has been presented. However, SICAM suffers from load current commutation problem during the dead time of bidirectional switches [4]. An active capacitive voltage clamp [3] composed of diode uncontrollable rectifier and auxiliary flyback converter can provide an alternative load current flowing path and solve commutation problem.…”

High efficiency two‐channel single‐stage switching amplifier with power switches multiplexing

“…However, it is too complicated as it uses three-leg with six power switches in the primary side. Moreover, there are no absorbing circuits in the secondary side of transformer, which may lead to severe voltage spikes during current commutation of secondary-side switches [2,5]. In this Letter, a two-channel SSA with multiplexing of primary-side power switches is proposed.…”