Crestron Electronics, Inc.

Other

Bren-tronics Batteries International, L.l.c.

Robert N Buono

Dennis Fink

Philipe H Gow

A multi-channel Class D audio amplifier is provided to substantially reduce channel-to-channel crosstalk by employing in each channel a local triangle ramp generator controlled by a single global digital timing signal. The noise critical timing/integrating capacitor for the triangle ramp generator resides locally in each channel and adjacent to the PWM comparator of that channel and referenced to the local ground of that channel. The amplifier can also include a duty cycle limitation circuit to limit output power availability depending on the impedance of any attached loads (speakers).

Reduced crosstalk and matched output power class D audio amplifier with oppositely polarized triangle waves

A feedback control circuit is described herein, comprising: an operational amplifier (op-amp) integrated circuit, wherein a first output of the op-amp provides a feedback error control signal; at least two transistors provided in a feedback path between the first output of the op-amp and an inverting input to the op-amp; and a plurality of discrete electrical components in the feedback path, such that in response to either an increase or decrease of an inverting input voltage at the inverting input that exceeds a predetermined level, at least one of the at least two transistors is turned on, and the feedback control circuit provides the feedback error control signal with an increased slew rate.

Accelerated transient response operational amplifier circuit

A feedback control circuit is described herein, comprising: an operational amplifier (op-amp) integrated circuit, wherein a first output of the op-amp provides a feedback error control signal; at least two transistors provided in a feedback path between the first output of the op-amp and an inverting input to the op-amp; and a plurality of discrete electrical components in the feedback path, such that in the response to either an increase or decrease of an inverting input voltage at the inverting input that exceeds a predetermined level, will speed up substantially. The feedback control circuit provides the feedback error control signal.

Transient response operational amplifier circuit

An inductor is provided, comprising: a first ferrite core piece and a second ferrite core piece, each of which are made of substantially similar materials, exhibit desired electromagnetic properties, and which are fashioned in a substantially similar manner and shape, and wherein each of the first and second ferrite core pieces comprises a substantially planar mating surface, a center post, and a wire core assembly channel, and wherein a first substantially planar mating surface of the first ferrite core piece is adapted to planarly mate with a second substantially planar mating surface of the second ferrite core piece; and a wire core assembly adapted to be substantially self-locating and self-centering about a first or second center post when located in a respective first or second wire core assembly channel.

Inductor apparatus optimized for low power loss in class-D audio amplifier applications and method for making the same

Inductor

Inductor core

Inductor core with coil

An audio amplifier system is described herein, comprising: an amplifier adapted to amplify an audio signal and comprising an output enable/disable input, the amplifier further adapted to receive an output enable signal at the output enable/disable input that enables/disables an output of the amplifier; a Zobel network connected to the output of the audio amplifier and comprising a Zobel capacitor and a Zobel resistor arranged such that they form a high pass frequency filter function and wherein the Zobel network is adapted to be substantially resistive when a frequency of an audio signal output from the audio amplifier is within a first frequency range; a mirroring resistor connected in parallel to the Zobel resistor and adapted to mirror a power that is dissipated in the Zobel resistor, and wherein a printed circuit board upon which the mirroring resistor is located is adapted to conduct heat generated by the mirroring resistor; a negative temperature coefficient (NTC) resistor located in close proximity to the mirroring resistor to receive the conducted heat from the mirroring resistor and which is adapted to change its resistance in response to the transferred heat such that its resistance goes down as a temperature of the NTC resistor increases; and a circuit adapted to generate the output enable signal, wherein the circuit generates an output enable signal that enables the output of the amplifier when the temperature of the Zobel resistor is below a first temperature, and wherein the circuit generates an output enable signal that disables the output of the amplifier when the temperature of the Zobel resistor is substantially the same or above the first temperature.

Overpower protection using a power-mirroring resistor

A rail balancing circuit is described herein for use with a power supply, the RBC comprising: a circuit adapted to respond to over-voltage and under-voltage conditions in the power supply that comprises a positive rail voltage source and a negative rail voltage source, such that any deviation from a balanced condition between the positive rail voltage source and the negative rail voltage source is substantially instantaneously corrected to bring both the positive and negative rail voltage sources back to the balanced condition.

Growing community of inventors

Ringwood, NJ, United States of America

Robert N Buono