Patent ID: 6642695
Filing Date: 2003-11-04
Classification: H02M,Y02B

Abstract:
A voltage mode boost converter comprising:a control signal generating circuit for generating a step-up control pulse signal with a fixed period and a modulated amplitude in response to a first reference voltage signal, a second reference voltage signal, a timing pulse signal, and a feedback voltage signal, the control signal generating circuit including: an amplitude control circuit having: a first comparator with a first input terminal, a second input terminal for receiving the first reference voltage signal, and a first output terminal for outputting an amplitude control signal, the first comparator being switched between a standby mode and an active mode in accordance with the timing pulse signal; a first resistor electrically connected to the first input terminal such that the feedback voltage signal is input into the first terminal through the first resistor; and a second resistor electrically connected between the first input terminal and the first output terminal, and a modulation circuit having: a second comparator with a third input terminal for receiving the feedback voltage signal, a fourth input terminal for receiving the second reference voltage signal, and a second output terminal; a logic gate with a fifth input terminal electrically connected to the second output terminal, a sixth input terminal for receiving the timing pulse signal, and a third output terminal; a PMOS transistor with a gate electrode electrically connected to the third output terminal, a source electrode for receiving the amplitude control signal, and a drain electrode; and an NMOS transistor with a gate electrode electrically connected to the third output terminal, a drain electrode electrically connected to the drain electrode of the PMOS transistor for outputting the step-up control pulse signal with the fixed period and the modulated amplitude, and a source electrode electrically connected to a ground; a step-up circuit electrically connected to the control signal generating circuit for adjusting an output voltage signal of the step-up circuit in accordance with the step-up control pulse signal with the fixed period and the modulated amplitude; and a feedback circuit electrically connected between the control signal generating circuit and the step-up circuit for generating the feedback voltage signal in accordance with the output voltage signal of the step-up circuit and for inputting the feedback voltage signal to the control signal generating circuit.