Class D amplifier
First Claim
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1. A class D amplifier comprising:
- a power switch for switching on/off a power supply supplying a supply voltage in response to a pulse width modulated signal;
a correction circuit for correcting a pulse width of said pulse width modulated signal to be input to said power switch in accordance with an amplitude of a feedback signal generated from an output of said power switch; and
an arithmetic unit for adjusting said amplitude of said feedback signal to be input to said correction circuit in accordance with a value of said supply voltage;
whereinsaid arithmetic unit includes;
a subtracter for subtracting a reference voltage generated on the basis of a dc component of said supply voltage from said feedback signal; and
an adder for adding a fixed dc voltage to an output of said subtracter, whereinan output of said adder is input to said correction circuit.
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Abstract
A pulse modulated signal (ei) output from a pulse modulator (1) and a feedback signal (ef) containing distortion caused by a power switch (3) are integrated in a first integrator (21) and a second integrator (24), respectively, and are input to input terminals of a comparator (25 or 29), respectively, so that a correction signal (Vc) is generated.
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Citations
4 Claims
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1. A class D amplifier comprising:
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a power switch for switching on/off a power supply supplying a supply voltage in response to a pulse width modulated signal; a correction circuit for correcting a pulse width of said pulse width modulated signal to be input to said power switch in accordance with an amplitude of a feedback signal generated from an output of said power switch; and an arithmetic unit for adjusting said amplitude of said feedback signal to be input to said correction circuit in accordance with a value of said supply voltage;
whereinsaid arithmetic unit includes; a subtracter for subtracting a reference voltage generated on the basis of a dc component of said supply voltage from said feedback signal; and an adder for adding a fixed dc voltage to an output of said subtracter, wherein an output of said adder is input to said correction circuit.
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2. A class D amplifier comprising:
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a power switch for switching on/off a power supply supplying a supply voltage in response to a pulse width modulated signal; a correction circuit for correcting a pulse width of said pulse width modulated signal to be input to said power switch in accordance with an amplitude of a feedback signal generated from an output of said power switch; and an arithmetic unit for adjusting said amplitude of said feedback signal to be input to said correction circuit in accordance with a value of said supply voltage; wherein said correction circuit includes; a first integrator for integrating said pulse width modulated signal; a second integrator for integrating a difference between said feedback signal and a reference voltage generated on the basis of a dc component of said supply voltage; and a comparator for comparing outputs of said first and second integrators, and an output of said comparator is input to said power switch. - View Dependent Claims (3, 4)
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Specification