Bogen Communications, Inc.

Isaac Ferstenberg

Thomas A Nelson

Berta Grushko

The present invention utilizes switching power amplifier technology to improve the performance of self-amplified speaker system. In contrast to analog Class A and Class AB amplifiers, the present invention utilizes a digital class D amplifier. Class D amplifiers are a pulse width modulated or digital switching amplifier configuration. The Class D amplifiers of the present invention includes 2-pole compensation feedback and power supply tracking that improves stability and total harmonic distortion over conventional power amplifiers. Class D amplifiers have an average electrical efficiency value of at least 65%. This level of electrical efficiency leads to reduction in the amount of power lost in the device or systems that result in heat generation. More specifically, the present invention utilizes Class D and other switching power amplifier topologies; amplitude scaling; and 2-pole compensation to increase electrical efficiency and physical operating range; and to reduce power supply requirements, heat generation and physical size of self-amplified speaker apparatus and systems. These design characteristics of the present invention provide speaker systems with the capability to operate with less total harmonic distortion and extend the operation range to at least twice the geographical distance or utilize at least twice as many self-amplified speaker systems.

Self-amplified loudspeakers with switching amplifier technology

Self-amplified loudspeaker

A regulator system includes a circuit regulating the output of a power supply such as a capacitive input filter power supply and preferably also a transformer and full-wave diode bridge. Included are a ramp generator, a zero crossing detector synchronizing the linear ramp cycle of the ramp generator with the input AC waveform, a peak voltage detector storing the maximum voltage reached by the ramp generator, a resistive divider to reduce the peak detector voltage to a scaled voltage value corresponding to a position in time in the AC waveform below the peak voltage, a timing window comparator comparing the scaled voltage with the instantaneous ramp voltage to establish a time window signal, a conduction angle ramp generator to synchronize the start of the maximum conduction ramp voltage with the beginning of the time window and the occurrence of the minimum conduction ramp voltage with the next zero crossing of the input AC waveform, an error amplifier comparing the average output voltage of the power supply to a reference voltage to generate an error voltage, and an output comparator comparing the error voltage to the conduction ramp voltage to activate power opto-triacs connected in series with the bridge at selected times during the input AC waveform based on the comparison.

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Edgewater, NJ, United States of America

Isaac Ferstenberg