| 摘要 |
The present invention relates to a Class D amplifier and method dynamically modulate the transition zone of a square wave as a function of the input signal. An embodiment of the amplifier a pseudo noise code generator to generate a signal for spreading processing which connects to a triangle oscillator to oscillate the spreading processing signal. A modulator having an audio input port such that the modulator dynamically modulates the oscillated spreading processing signal as a function of the input signal is also included. Dithering the frequency with a Pseudo Noise (PN) code spreads the spectrum of the pulse width modulated (PWM) output; thus, eliminating the need for a demodulating filter. The modulator couples to a power amplifying switching circuit, being operative to generate a power amplified audio drive signal for application to an audio output load port in accordance with the output of the modulator. The Class D amplifier provides EMI reduction and high stability using very simple circuitry; thereby, reducing cost, circuit board area, and design time.
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