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US 6,388,514 B1Granted
Class D high voltage amplifier system with adaptive power supply
AssigneeInternational Rectifier Corporation
InventorsRay King, John Parry, Jonathan Adams
Life of this patent
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Abstract
A Class D amplifier system utilizing high voltage level shifting technology and an adaptive power supply which adjusts the magnitude of the output voltage based on audio input levels to reduce switching losses at low audio input levels. The amplifier system of the present invention also removes any DC offset at the output by providing an equal positive and negative power supply with respect to ground.
Claims11
A system for amplifying an input signal, comprising:
- level-shift PWM circuitry for level-shifting and converting the input signal into a pulse width modulated signal;
- gate drive circuitry for receiving the level-shifted pulse width modulated input signal and converting the signal into gate drive signals for controlling upper and lower transistor switches arranged in a half-bridge configuration to alternatively switch a positive and negative voltage applied thereto, thereby generating an output signal having a switching frequency;
- adaptive power supply control circuitry for adjusting the magnitude of the positive and negative voltage switched by the upper and lower transistor switches in the half-bridge arrangement in accordance with the magnitude of the input signal, such that when the input signal is absent, the positive and negative voltage switched is reduced to a low level to reduce switching losses and, when the input signal increases, the positive and negative voltage switched is increased by an amount proportional to the input signal level;
- and
- filter circuitry for removing the switching frequency from the output signal to generate an amplified system output signal to be applied to a load.
2 more elements
A method for amplifying an input signal, comprising the steps of:
- level-shifting and converting the input signal into a pulse width modulated signal;
- converting the level-shifted pulse width modulated input signal into gate drive signals for controlling upper and lower transistor switches arranged in a half-bridge configuration to alternatively switch a positive and negative voltage applied thereto, thereby generating an output signal having a switching frequency;
- adjusting the magnitude of the positive and negative voltage switched by the upper and lower transistor switches in the half-bridge arrangement in accordance with the magnitude of the input signal, such that when the input signal is absent, the positive and negative voltage switched is reduced to a low level to reduce switching losses and, when the input signal increases, the positive and negative voltage switched is increased by an amount proportional to the input signal level;
- and
- removing the switching frequency from the output signal to generate an amplified system output signal to be applied to a load.
2 more elements
Dependencies are inferred from the claim text.