摘要:
The present invention achieves technical advantages as a high performance analog charge pumped phase locked loop (PLL)(10) with process and temperature compensation in closed loop bandwidth. The PLL reduces the variation in bandwidth and stability by making the product KVCO*ICP independent of process and temperature variation. The PLL achieves a higher performance than existing PLL architectures, achieving a high dynamic range up to at least 110 dB, such that a PWM class-D amplifier is realizable with this PLL. The PLL has a constant bandwidth and damping factor while using an analog charge pump (16).
摘要:
The present invention achieves technical advantages as a high performance analog charge pumped phase locked loop (PLL)(10) with process and temperature compensation in closed loop bandwidth. The PLL reduces the variation in bandwidth and stability by making the product KVCO*ICP independent of process and temperature variation. The PLL achieves a higher performance than existing PLL architectures, achieving a high dynamic range up to at least 110 dB, such that a PWM class-D amplifier is realizable with this PLL. The PLL has a constant bandwidth and damping factor while using an analog charge pump (16).
摘要:
A digital audio system including a digital phase-locked-loop circuit for generating a pulse-width-modulation (PWM) clock signal, applied to a pulse-code-modulation to pulse-width-modulation converter, is disclosed. The digital phase-locked loop includes a phase detector for measuring phase error between a reference signal and a feedback signal. A digital version of the phase error, after filtering by a loop filter, is converted to a digital delay control word that is sampled at twice its frequency. Successive samples of the delay control word control the propagation delay of first and second delay cells in an oscillator. The use of successive samples at substantially twice the frequency of change of the delay control word effectively realizes the sum of a sinc filter and a comb filter, which greatly suppresses the effects of jitter in the reference signal to the digital phase-locked loop.
摘要:
A digital audio system including a digital phase-locked-loop circuit for generating a pulse-width-modulation (PWM) clock signal, applied to a pulse-code-modulation to pulse-width-modulation converter, is disclosed. The digital phase-locked loop includes a phase detector for measuring phase error between a reference signal and a feedback signal. A digital version of the phase error, after filtering by a loop filter, is converted to a digital delay control word that is sampled at twice its frequency. Successive samples of the delay control word control the propagation delay of first and second delay cells in an oscillator. The use of successive samples at substantially twice the frequency of change of the delay control word effectively realizes the sum of a sinc filter and a comb filter, which greatly suppresses the effects of jitter in the reference signal to the digital phase-locked loop.
摘要:
A closed loop amplifier system comprising a modulator that provides a pulse-width modulated (PWM) output signal based on an input signal, the modulator having a variable closed loop transfer function. The system also comprises a ramp generator that provides a ramp signal to the modulator, the variable closed loop transfer function of the modulator varying as a function of the ramp signal. The system further comprises a controller that controls the ramp generator to provide the ramp signal to adjust the variable closed loop transfer function during transitions between operating states of the amplifier system.
摘要:
A closed loop amplifier system comprising a modulator that provides a pulse-width modulated (PWM) output signal based on an input signal, the modulator having a variable closed loop transfer function. The system also comprises a ramp generator that provides a ramp signal to the modulator, the variable closed loop transfer function of the modulator varying as a function of the ramp signal. The system further comprises a controller that controls the ramp generator to provide the ramp signal to adjust the variable closed loop transfer function during transitions between operating states of the amplifier system.