Patent ID: 8358118

Claim:
A current mode boost converter comprising: an input end, for receiving an input voltage; an output end, for outputting an output voltage; a first inductor, comprising a first end coupled to the input end, and a second end; a feedback module, coupled to the output end, for generating a feedback signal according to the output voltage; a switch transistor, comprising a source end, a drain end coupled to the second end of the first inductor, and a gate end, for determining whether the first inductor is electrically connected to a ground end according to a second switch signal; an output module, comprising: a diode, coupled between the drain end of the switch transistor and the output end; an output resistor, coupled to the output end; and an output capacitor, coupled between the output resistor and the ground end; a current sensor, coupled between the source end of the switch transistor and the ground end, for sensing an inductor current of the first inductor to generate a sensing current; a current sense circuit, coupled to the current sensor, for amplifying the sensing current to duplicate the inductor current as a first mirror inductor current and a second mirror inductor current; a slope compensation circuit, for generating a first slope compensation current and a second slope compensation current; a first resistor, for converting a summation of the first mirror inductor current and the first slope compensation current into a compensation voltage; an error amplifier, coupled to the feedback module, for amplifying a difference between the feedback signal and a first reference signal to generate a difference voltage; a pulse width modulation (PWM) compensation circuit, coupled to the error amplifier, for compensating a frequency response of the boost converter according to the difference voltage to generate a compensation result; a first comparator, coupled to the current sense circuit, the slope compensation circuit, the resistor and the PWM compensation circuit, for comparing the compensation voltage and the compensation result to generate a PWM signal; a second comparator, coupled to the feedback module, for comparing the feedback signal and a division voltage of the first reference voltage to generate a PWM trigger signal; a third comparator, for comparing a second reference voltage and a threshold voltage to generate a pulse frequency modulation (PFM) trigger signal; an oscillator, for generating an oscillating signal; and a modulation control circuit, coupled to the first comparator, the second comparator, the third comparator and the oscillator, for generating a first switch signal according to the PWM trigger signal, the PFM trigger signal, the PWM signal and the oscillating signal.