| 摘要 |
PROBLEM TO BE SOLVED: To provide a DC-DC converter which can perform stable PWM operation by generating a duty control signal, by using a portion of a linear slope of a triangle wave. SOLUTION: The DC-DC converter includes: an error amplifying circuit 11 to which a reference voltage and an return input of an output voltage which is generated on the basis of the on/off-operation of an output transistor 3, and which outputs an error signal generated by amplifying a difference of these voltages; a PWM comparison circuit 12, which compares a triangle wave signal output from a triangle wave oscillation circuit 13 and the error signal, and outputs the duty control signal having a duty ratio, based on the comparison result; a pulse-width control circuit 18, which controls the pulse width of the duty control signal output from the PWM comparison circuit 12; and a drive circuit 14 which drives the output transistor 3, on the basis of an output signal from the pulse-width change circuit 18. COPYRIGHT: (C)2009,JPO&INPIT
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