| 摘要 |
PROBLEM TO BE SOLVED: To provide a switching circuit with a simple configuration, which is capable of eliminating a shunt resistor for detecting an output current and has a protective circuit for protecting the circuit by completely detecting an overcurrent or short-circuit condition. SOLUTION: This switching circuit comprises a switching control circuit, an integrator, and the protective circuit. The switching control circuit outputs a pulse signal for determining the conduction period of a switching device corresponding to the output voltage of the switching device for switching an input voltage. The integrator integrates the pulse signal and determines a voltage signal proportional to the frequency or pulse duration of the pulse signal. The protective circuit changes the frequency or pulse duration of the pulse signal if the output voltage of the integrator is larger than a reference voltage to limit the output current of the switching circuit. COPYRIGHT: (C)2004,JPO
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