| 摘要 |
PROBLEM TO BE SOLVED: To enhance load transient response of a switching regulator by immediately returning to PWM mode operation when a steep load is applied during burst operation. SOLUTION: A control circuit 4 for forcibly starting oscillation of a PWM controller by detecting application of a steep load to the output side during burst operation is provided. The control circuit 4 has differential amplifiers 7 and 8, a P channel MOS transistor TR2, resistors R3 and R4, and a capacitor C8. When a steep load is applied and the output voltage division potential becomes lower than a predetermined threshold, output of the differential amplifier 7 becomes high to turn on a transistor TR2 and a current flows through the resistor R4 and the capacitor C8. When a differential voltage produced across the resistor R4 by a current flowing from the capacitor C8 toward the resistor R4 reaches a predetermined value, a signal for starting oscillation is delivered from the differential amplifier 8 to the PWM controller 2. COPYRIGHT: (C)2007,JPO&INPIT
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