DC-DC converter
AssigneeRicoh Company, Ltd.
InventorShinichiro Yamada
Life of this patent
Estimating the term…
Abstract
A DC-DC converter includes an error amplifying circuit to output an error signal by amplifying differences between a reference voltage and a feedback voltage for an output voltage generated by switching an output transistor between on and off, a triangular wave generation circuit to generate a triangular wave, a PWM comparison circuit to compares the triangular wave with the error signal and output a duty control signal having a duty ratio based on the comparison, a pulse width control circuit to control a pulse width of the duty control signal output from the PWM comparison circuit, and a drive circuit to drive the output transistor according to a signal output from the pulse width control circuit.
Claims13
A DC-DC converter comprising:
- an error amplifying circuit to output an error signal by amplifying a difference between a reference voltage and a feedback voltage for an output voltage generated by switching an output transistor between on and off;
- a triangular wave generation circuit to generate a triangular wave;
- a PWM comparison circuit to compare the triangular wave with the error signal and output a duty control signal having a duty ratio based on the comparison;
- a pulse width control circuit to control a pulse width of the duty control signal output from the PWM comparison circuit;
- and
- a drive circuit to drive the output transistor according to a signal output from the pulse width control circuit,
- wherein the pulse width control circuit comprises:
- a first circuit to reduce the pulse width of the duty control signal output from the PWM comparison circuit by a predetermined amount;
- a second circuit to increase the pulse width of the duty control signal output from the PWM comparison circuit by a predetermined amount;
- and
- a selector to select and output one of signals output from the first circuit and the second circuit,
- the selector being controlled based on the output voltage and an input voltage.
An electronic apparatus, comprising:
- a memory unit that stores data;
- a processing unit that processes selected data obtained from the memory unit;
- and
- a DC-DC converter that supplies operational power to the memory unit and processing unit, the DC-DC converter comprising:
- an error amplifying circuit to output an error signal by amplifying a difference between a reference voltage and a feedback voltage for an output voltage generated by switching an output transistor between on and off;
- a triangular wave generation circuit to generate a triangular wave;
- a PWM comparison circuit to compare the triangular wave with the error signal and output a duty control signal having a duty ratio based on the comparison;
- a pulse width control circuit to control a pulse width of the duty control signal output from the PWM comparison circuit;
- and
- a drive circuit to drive the output transistor according to a signal output from the pulse width control circuit,
- wherein the pulse width control circuit comprises:
- a first circuit to reduce the pulse width of the duty control signal output from the PWM comparison circuit by a predetermined amount;
- a second circuit to increase the pulse width of the duty control signal output from the PWM comparison circuit by a predetermined amount;
- and
- a selector to select and output one of signals output from the first circuit and the second circuit,
- the selector being controlled based on the output voltage and an input voltage.
A method for controlling a DC-DC converter, the method comprising:
- outputting an error signal by amplifying a difference between a reference voltage and a feedback voltage for an output voltage generated by switching an output transistor between on and off;
- generating a triangular wave signal;
- comparing the triangular wave signal with the error signal, and outputting a duty control signal having a duty ratio based on the comparison;
- controlling a pulse width of the duty control signal by reducing the pulse width of the duty control signal by a predetermined amount for output as a reduced signal, increasing the pulse width of the duty control signal by a predetermined amount for output as an increased signal, selecting one of the reduced signals and the increased signal for output as a control signal, and controlling the selection based on the output voltage and an input voltage;
- and
- driving the output transistor according to the control signal.
Dependencies are inferred from the claim text.