Load detection device for audio amplifier system

A load detection device for an audio amplifier system, the audio amplifier system comprises a first load end and a second load end that are coupled to a speaker, the load detection device comprising:

• a signal output circuit, coupled to the first load end and the second load end for generating and outputting a forced current to the first load end, and generating a bias signal, a first output signal related to a level of the first load end, a second output signal related to a level of the second load end, and a feedback signal depending on the forced current;
• a reference voltage generation circuit, coupled to the signal output circuit to receive the bias signal, and generates a reference signal output according to the bias signal;
• a comparison circuit, coupled to the signal output circuit to receive the first and second output signals, and coupled to the reference voltage generation circuit to receive the reference signal output, and the reference signal output is compared with the first output signal and the second output signal to produce an accurate comparison output used to indicate a load state of the speaker;
• a sensing circuit, coupled to the signal output circuit to receive the feedback signal, and generates a sensing signal according to the feedback signal;
• a detection circuit, coupled to the sensing circuit to receive the sensing signal, and coupled to the signal output circuit to receive the first output signal and the second output signal, and generates a rough detection output used to indicate the load state of the speaker according to the sensing signal, the first output signal, and the second output signal;
• a logic circuit, coupled to the comparison circuit and the detection circuit to respectively receive the accurate comparison output and the rough detection output, and obtains the load state of the speaker according to the accurate comparison output and the rough detection output to produce a detection result;
• and
• a control circuit, used to generate an enabling signal and output to the signal output circuit, the comparison circuit, the sensing circuit, and the logic circuit, so as to enable the signal output circuit, the comparison circuit, the sensing circuit, and the logic circuit.