Smart power stage circuit of power converter and current monitoring circuit thereof

A smart power stage (SPS) circuit of a power converter, comprising:

• an output stage circuit, configured to receive an input voltage so that the power converter provides an output voltage and an inductor current;
• and
• a driver, coupled to the output stage circuit, the driver comprising:
• a driving circuit, coupled to the output stage circuit and configured to receive a pulse-width modulation (PWM) signal and provide a driving signal to the output stage circuit;
• a monitoring signal generation circuit, configured to receive the PWM signal, the input voltage and the output voltage to generate a monitoring signal related to the inductor current, the monitoring signal comprising a simulated current signal;
• and
• a compensation circuit, coupled to the monitoring signal generation circuit,
• wherein when the simulated current signal is greater than a default value, the compensation circuit generates a compensation signal superposing to the simulated current signal;
• wherein the monitoring signal circuit comprises:
• first current generation circuit, configured to receive the input voltage and the output voltage and generate the simulated current signal according to the input voltage and the output voltage;
• a superposing circuit, coupled to the first current generation circuit and the compensation circuit respectively, configured to superpose the compensation signal on the simulated current signal;
• a second current generation circuit configured to sense the inductor current to generate a sensing current signal;
• and
• a switch, coupled to the first current generation circuit and the second current generation circuit, which is controlled by the PWM signal to selectively output the simulated current signal or the sensing current signal as the monitoring signal, and
• wherein the compensation circuit comprises:
• an error amplifying circuit having a first input terminal, a second input terminal and an output terminal, the first input terminal receiving the monitoring signal and the second input terminal receiving the default value, the error amplifying circuit generating an error amplification signal according to the monitoring signal and the default value;
• a transistor having a first terminal, a second terminal and a control terminal, the control terminal being coupled to the output terminal of the error amplifying circuit, and the second terminal being coupled to the second input terminal of the error amplifying circuit;
• a compensation signal generation circuit coupled to the first terminal of the transistor and configured to selectively generate the compensation signal according to the error amplification signal, and
• a resistor coupled to the second input terminal of the error amplifying circuit, wherein the resistor is configured to adjust a magnitude of the compensation signal.