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US 6,611,169 B2Granted
Power supply regulation and protection circuit for audio power amplifier
AssigneeGibson Guitar Corp.
InventorEric Mendenhall
Life of this patent
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Abstract
An audio power amplifier including a rail voltage detection circuit connected to a feedback generator and a rail voltage, the detection circuit is adapted to detect an overvoltage or undervoltage condition and control the feedback signal to a regulated switching power supply to adjust the rail voltage. Additional protection is provided through thermal stress detection and output fault detection to control the feedback signal and protect the audio power amplifier.
Claims20
An apparatus for amplifying an audio signal, comprising:
- a regulated switching power supply adapted to produce a positive and negative rail voltages in relation to a midpoint voltage, the regulated switching power supply including a peak current mode control system using a voltage error amplifier adapted to receive a feedback signal;
- an audio frequency amplifier electrically connected to the midpoint and rail voltages of the regulated switching power supply and adapted to receive and amplify the audio signal;
- a feedback generator connected between at least one rail and the midpoint voltage, the feedback generator adapted to proportionally divide the voltage between the midpoint voltage and the rail voltage to generate the feedback signal and a reference voltage;
- and
- a rail overvoltage detection circuit connected to the feedback generator and at least one rail voltage, the rail overvoltage detection circuit adapted to detect an overvoltage on the at least one rail voltage and adjust the feedback generator's reference voltage to control the feedback signal such that the regulated switching power supply will adjust the at least one rail voltage.
2 more elements
The rail overvoltage detection circuit adapted to monitor the negative rail, the rail overvoltage detection circuit comprising:
- a resistor and the collector-emitter flow of a transistor electrically connected between the proportional reference voltage and the negative rail;
- and
- a voltage divider electrically connected to the base of the transistor and further connected between the midpoint voltage and the rail voltage, the voltage divider adapted to increase transistor bias to increase current flow and reduce the proportional reference voltage in the voltage regulator and thereby adjust the feedback generator's reference voltage to control the feedback signal.
An apparatus for amplifying an audio signal, comprising:
- a regulated switching power supply adapted to produce a positive and negative rail voltages in relation to a midpoint voltage, the regulated switching power supply including a peak current mode control system using a voltage error amplifier adapted to receive a feedback signal;
- an audio frequency amplifier electrically connected to the midpoint and rail voltages of the regulated switching power supply and adapted to receive and amplify the audio signal;
- a feedback generator connected between at least one rail and the midpoint voltage, the feedback generator adapted to proportionally divide the voltage between the midpoint voltage and the rail voltage to generate the feedback signal and a proportional reference voltage;
- and
- a rail undervoltage detection circuit connected to the feedback generator and at least one rail voltage, the rail undervoltage detection circuit adapted to detect an undervoltage on the at least one rail voltage and adjust the feedback generator's reference voltage to control the feedback signal such that the regulated switching power supply will adjust the at least one rail voltage.
2 more elements
An apparatus for amplifying an audio signal, comprising:
- a regulated switching power supply adapted to produce a positive and negative rail voltages in relation to a midpoint voltage, the regulated switching power supply including a peak current mode control system using a voltage error amplifier adapted to receive a feedback signal;
- an audio frequency amplifier electrically connected to the midpoint and rail voltages of the regulated switching power supply and adapted to receive and amplify the audio signal;
- a feedback generator connected between at least one rail and the midpoint voltage, the feedback generator adapted to proportionally divide the voltage between the midpoint voltage and the rail voltage to generate the feedback signal and a proportional reference voltage;
- and
- a thermal fault detection circuit connected to the feedback generator and at least one rail voltage, the rail thermal fault detection circuit adapted to detect a thermal overload on the amplifier and adjust the feedback generator's reference voltage to control the feedback signal such that the regulated switching power supply will lower the rail voltage to protect the amplifier.
2 more elements
An apparatus for amplifying an audio signal, comprising:
- a regulated switching power supply adapted to produce a positive and negative rail voltages in relation to a midpoint voltage, the regulated switching power supply including a peak current mode control system using a voltage error amplifier adapted to receive a feedback signal;
- an audio frequency amplifier electrically connected to the midpoint and rail voltages of the regulated switching power supply and adapted to receive and amplify the audio signal;
- a feedback generator connected between at least one rail and the midpoint voltage, the feedback generator adapted to proportionally divide the voltage between the midpoint voltage and the rail voltage to generate the feedback signal and a proportional reference voltage;
- and
- a fault detection circuit connected to the feedback generator and at least one rail voltage, the fault detection circuit adapted to detect a low impedance load on the amplifier and adjust the feedback generator's reference voltage to control the feedback signal such that the regulated switching power supply will lower the rail voltage to protect the amplifier.
2 more elements
Dependencies are inferred from the claim text.