| 摘要 |
PROBLEM TO BE SOLVED: To provide a DC-DC converter that detects an overvoltage state, quickly reduces an output voltage for returning to normal control, and prevents the occurrence of undershoot. SOLUTION: The DC-DC converter comprises a control circuit 100 for alternately turning on and off a main switching element 1, a rectifying switching element 2, an inductor 4, a smoothing means 5, and a main switching element 1 for controlling an output voltage and the rectifying switching element 2 by a prescribed on/off time ratio; and an overvoltage protection circuit 50a for detecting the overvoltage state of the output voltage Vout, and connecting a resistor circuit 3 having a prescribed resistance value to the switching element 2 for rectification in parallel when the overvoltage state is detected. Discharging is made via the resistance circuit 3 when an overvoltage is detected, thus gently reducing the output voltage for suppressing the occurrence of undershoot. COPYRIGHT: (C)2006,JPO&NCIPI
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