| 摘要 |
PROBLEM TO BE SOLVED: To equalize the on/off duty of a transistor MP0 and the duty of an output modulation signal of a comparator which conducts pulse width modulation to provide a constant dead time. SOLUTION: An error signal Ec between an output detection signal Eo and a reference value Er is obtained by an error amplifier 4, and a pulse width modulation signal PWM1 is obtained by comparing by the comparator 2 the error signal Ec with a triangular wave signal Et output from a triangular wave/rectangular wave oscillation circuit 1, and the transistor MP0 is driven by a driver circuit 5. A pulse width modulation signal PWM2 is obtained in a pulse generation circuit 3 by the output signal PWM1 of the comparator 2 and a rectangular wave signal Ek output from the triangular wave/rectangular wave oscillation circuit 1 to drive a transistor MN0 by a driver circuit 6. The pulse generation circuit has a capacitor C3 which is recharged by the AND signal of the pulse width modulation signal PWM1 and the rectangular wave signal Ek and a comparator 302 which compares the charging voltage of the capacitor C3 with the reference value V1 to output the pulse width modulation signal PWM2. COPYRIGHT: (C)2009,JPO&INPIT
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