Current sensing signal comparing device, and current sensing signal comparing method

A current sensing signal comparing device for a switching circuit, comprising:

• a current sensing circuit for sensing a current signal of the switching circuit and outputting a current sensing signal accordingly;
• a control unit for outputting a control signal according to a relationship between a switching frequency of the switching circuit and a predetermined frequency, or according to a relationship between an output voltage of the switching circuit and a predetermined voltage, or according to a relationship between a switch component temperature of the switching circuit and a predetermined switch component temperature, or according to a relationship between an ambient temperature of the switching circuit and a predetermined ambient temperature;
• an offsetting circuit connected to the control unit, wherein the offsetting circuit is configured to compensate a first signal selected from a group consisting of the current sensing signal and a constant current reference signal to generate a second signal;
• and
• a constant current compare unit having a first input terminal receiving the second signal and having a second input terminal receiving a third signal selected from the group consisting of the current sensing signal and a constant current reference signal which is different from the first signal to generate a constant current control signal.

A current sensing signal comparing method for a switching circuit, comprising the steps of:

• sensing a current signal of the switching circuit to generate a current sensing signal;
• receiving a constant current reference signal;
• generating a control signal according to a relationship between a switching frequency of the switching circuit and a predetermined frequency, or according to a relationship between an output voltage of the switching circuit and a predetermined voltage, or according to a relationship between a switch component temperature of the switching circuit and a predetermined switch component temperature, or according to a relationship between an ambient temperature of the switching circuit and a predetermined ambient temperature;
• compensating a first signal selected from a group consisting of the current sensing signal and the constant current reference signal to generate a second signal according to the control signal;
• and
• comparing the second signal and a third signal selected from a group consisting of the current sensing signal and the constant current reference signal being different from the first signal to generate a constant current control signal.

A current sensing method for a switching circuit, comprising the steps of:

• sensing a current signal of the switching circuit to generate a current sensing signal;
• generating a control signal according to a relationship between a switching frequency of the switching circuit and a predetermined frequency, or according to a relationship between an output voltage of the switching circuit and a predetermined voltage, or according to a relationship between a switch component temperature of the switching circuit and a predetermined switch component temperature, or according to a relationship between an ambient temperature of the switching circuit and a predetermined ambient temperature;
• and
• compensating the current sensing signal according to the control signal to generate a compensated current sensing signal.