| 摘要 |
PROBLEM TO BE SOLVED: To obtain a switching regulator that reduces a variation in efficiency during a light load and a variation in ripple of an output voltage while reducing a variation in pulse width of a pulse signal output from a pulse-width limiting circuit, and its pulse-width limit-value adjusting method. SOLUTION: In a pulse-width limiting circuit 6, a switch SW11 is provided between an output end of an inverter 13 and a ground voltage or between an output end of a constant current source 12 and a ground voltage so as to execute switching according to a test signal TEST input from the outside. During the test, a power-supply current flowing in the constant current source 12 when the switch SW11 is turned off and a power-supply current flowing in the constant current source 12 when the switch SW11 is turned on are measured so as to accurately measure a constant current i2. A reference current i1 is adjusted so that the constant current i2 becomes a desired value. COPYRIGHT: (C)2009,JPO&INPIT
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