| 摘要 |
PROBLEM TO BE SOLVED: To provide a switching amplifier which is capable of detecting an overcurrent with a prescribed time delay when the overcurrent flows to a switch element. SOLUTION: Transistors Q2 and Q3 are turned on to output a bootstrap voltage +VB to a capacitor C3 when a MOSFET 15 is in the on state, and are turned off to cut off the output of the voltage +VB to the capacitor when the MOSFET 15 is in the off state. The capacitor C3 is charged up to a voltage corresponding to a current flowing to the MOSFET 15, by the voltage +VB and supplies the charged voltage to a detection input terminal 21. When the voltage inputted to the detection input terminal 21 is equal to or higher than a reference voltage, a driver 11 judges that an overcurrent flows to the MOSFET 15, and stops the output of a driving signal. COPYRIGHT: (C)2008,JPO&INPIT
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