PWM bridge amplifier with input network configurable for analog or digital input not needing a triangular wave generator

A Class-D power amplifier for receiving analog and digital signals, the amplifier comprising:

• an input network;
• a first amplifying module for a direct PWM output amplifying channel, and including an inverting input connected to the input network for receiving a square wave signal;
• and
• a second amplifying module for an inverted PWM output amplifying channel, and including an inverting input connected to the input network for receiving the square wave signal;
• each of the first and second amplifying modules comprising
• an operational amplifier, having a voltage mode noninverting input and a current mode inverting input,
• a loop filter connected to the operational amplifier which together define a slope integrator for outputting a signal of a substantially triangular waveform,
• at least one logic inverter connected to an output of the slope integrator and which outputs a logic PWM signal,
• an output power stage which converts the logic PWM signal output by the at least one logic inverter to a PWM signal, and
• a feedback resistor connecting an output of the output power stage to the current mode inverting input of the operational amplifier.

A method of Class-D power amplification for analog and digital signals, the method comprising the steps of:

• providing an input network;
• connecting a first amplifying module for a direct PWM output amplifying channel to the input network, the first amplifying module including an inverting input for receiving a square wave signal;
• and
• connecting a second amplifying module for an inverted PWM output amplifying channel to the input network, the second amplifying module including an input for receiving the square wave signal;
• each of the first and second amplifying modules comprising
• a switching output operational amplifier, having a voltage mode noninverting input, a current mode inverting input and a loop filter which define a slope integrator for outputting a signal of a substantially triangular waveform,
• at least ore logic inverter connected to an output of the slope integrator and which outputs a logic PWM signal,
• an output power stage which converts the logic PWM signal output by the at least one logic inverter to a PWM signal, and
• a feedback resistor connecting an output of the output power stage to the current mode inverting input of the switching output operational amplifier.

A method of Class-D power amplification for analog and digital signals, the method comprising the steps of:

• providing an input network;
• connecting a first amplifying module for a direct PWM output amplifying channel to the input network, the first amplifying module including an inverting input for receiving a square wave signal;
• and
• connecting a second amplifying module for an inverted PWM output amplifying channel to the input network, the second amplifying module including an input for receiving the square wave signal;
• each of the first and second amplifying modules comprising an operational amplifier, a loop filter connected to the operational amplifier which together define a slope integrator, at least one logic gate connected to an output of the slope integrator, an output power stage connected to an output of the at least one logic gate, a resistive divider having an intermediate node and connected to an output of the output power stage, and a feedback resistor connected to the intermediate node and to an input of the operational amplifier.

A Class-D power amplifier for receiving analog and digital signals, the amplifier comprising:

• an input network;
• a first amplifying module for a direct PWM output amplifying channel, and connected to the input network;
• a second amplifying module for an inverted PWM output amplifying channel, and connected to the input network;
• and
• each of the first and second amplifying modules comprising
• an operational amplifier,
• a loop filter connected to the operational amplifier which together define a slope integrator,
• at least one logic gate connected to an output of the slope integrator,
• an output power stage connected to an output of the logic gate,
• a resistive divider having an intermediate node and connected to the output of the output power stage, and
• a feedback resistor connected to the intermediate node and to an input of the operational amplifier.

A Class-D power amplifier for receiving analog and digital signals, the amplifier comprising:

• a first amplifying module for a direct PWM output amplifying channel;
• and
• a second amplifying module for an inverted PWM output amplifying channel;
• an input network connected to the first and second amplifying modules and comprising
• a first input node for receiving one of a square waveform clock signal and a PWM digital input signal,
• a second input node for receiving an inverted PWM digital input signal,
• a third input node for receiving a constant reference voltage,
• a fourth input node for receiving an analog input signal, the fourth input node being connected in common with the third input node when the first input node receives the PWM digital input signal, and
• first and second four-position switches for selectively connecting the four input nodes to the first and second amplifying modules.