Modulation apparatus for class D switching amplifier
A modulation apparatus for a class D switching amplifier is capable of reducing power consumption of an Electro-Migration Interface (EMI) of an output end and a gate driver end in a zero input signal. The modulation apparatus for a class D switching amplifier includes a control unit for detecting and outputting a control signal which is a common signal component of a first modulation signal modulated by using a first input signal and a second modulation signal modulated by using a second input signal; and is characterized by feedback of a first output signal, a second output signal and a common output signal outputted by using the first modulation signal, the second modulation signal and the control signal through an input of the modulation apparatus.
1. A modulation apparatus for a class D switching amplifier, the modulation apparatus being a modulation apparatus for a switching amplifier outputting one or more output signals using a first input signal and a second input signal, comprising:
a first modulation part for modulating the first input signal and outputting a first modulated signal;
a second modulation part for modulating the second input signal and outputting a second modulated signal; and
a control part for detecting and outputting a control signal that is a common signal component of the first modulated signal and the second modulated signal,
wherein the control part further outputs: a first difference signal that is a difference signal between the first modulated signal and the control signal; and a second difference signal that is a difference signal between the second modulated signal and the control signal.
2. The modulation apparatus of claim 1 , wherein a first output signal, a second output signal, and a common output signal that are output using the first modulated signal, the second modulated signal, and the control signal are fed back to input of the modulation apparatus.
3. The modulation apparatus of claim 1 , further comprising:
a power stage part for buffering and amplifying the first difference signal and the second difference signal and outputting a first output signal and a second output signal; and
a delay cell part for buffering the control signal and outputting a common output signal.
4. The modulation apparatus of claim 3 , wherein:
the first output signal and the common output signal are fed back to input of the first modulation part, and
the second output signal and the common output signal are fed back to input of the second modulation part.
5. The modulation apparatus of claim 3 , wherein the power stage part comprises:
a first gate driver for buffering the first difference signal and a first power transistor for amplifying a buffered signal; and
a second gate driver for buffering the second difference signal and a second power transistor for amplifying a buffered signal.
6. The modulation apparatus of claim 1 , wherein:
the first modulation part comprises:
a first integrator for receiving the first input signal, receiving some or all of one or more output signals via feedback, and integrating the received signals; and
a first comparator for comparing an output signal of the first integrator with a reference signal and outputting the first modulated signal, and
the second modulation part comprises:
a second integrator for receiving the second input signal, receiving some or all of the one or more output signals via feedback, and integrating the received signals; and
a second comparator for comparing an output signal of the second integrator with the reference signal and outputting the second modulated signal.
7. The modulation apparatus of claim 6 , wherein:
some or all of the one or more output signals that are fed back to input of the first integrator are signals generated based on the first modulated signal and the control signal, and
some or all of the one or more output signals that are fed back to input of the second integrator are signals generated based on the second modulated signal and the control signal.