| 摘要 |
PROBLEM TO BE SOLVED: To provide a current mode DC-DC converter whose output voltage is not significantly varied even if a load current is suddenly varied. SOLUTION: If a load current Io is suddenly varied, a feed forward circuit 41 detects the variation component of the load current Io and adds the variation component to a detection signal of a coil current I2. A current mode control circuit 51 compares a value obtained by adding the variation component of the load current Io to the detection signal of the coil current I2 with an error signal from an error amplifier A1 and controls a switching operation of a switching device Q1 according to the comparison result. With such a constitution, the coil current I2 is quickly varied following the sudden variation of the load current Io and a variation component of an output voltage Vo can be reduced.
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