Patent ID: 8120348

Claim:
A power converter with improved line transient response, comprising: a power stage circuit including at least one power transistor switch which operates to convert an input voltage to an output voltage; an error amplifier comparing a feedback signal with a reference signal to generate an error signal; an input voltage instant variation extraction circuit extracting an instant variation of the input voltage and generating a signal relating to the instant variation, the input voltage instant variation extraction circuit including: a first divided voltage circuit including a first resistor and a second resistor connected in series, and a first capacitor connected in parallel with the first resistor, wherein the first resistor has one terminal coupled to the input voltage and another terminal coupled to one terminal of the second resistor, and the second resistor has another terminal coupled to ground; a second divided voltage circuit including a third resistor and a fourth resistor connected in series, and a second capacitor connected in parallel with the fourth resistor, wherein the third resistor has one terminal coupled to the input voltage and another terminal coupled to one terminal of the fourth resistor, and the fourth resistor has another terminal coupled to ground; and an operational amplifier having inputs coupled respectively to a node between the first resistor and the second resistor, and to a node between the third resistor and the fourth resistor; and a pulse width modulation (PWM) comparator generating a PWM signal according to at least a ramp signal, the error signal, and the signal relating to the instant variation, to thereby control the operation of the power transistor switch in the power stage circuit.