| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a protection circuit for a power supply amplifier which controls a current within a range of a predetermined value without interrupting the supply of a voltage during generation of an overcurrent due to occurrence of a short-circuit or the like in a piezoelectric actuator element functioning as a load, and to notify the outside that the protection circuit starts a current limiting operation with a simple structure. <P>SOLUTION: The power supply amplifier includes a driving power source 12, an amplifier circuit 11 which forms a voltage waveform on the basis of an input signal on receiving a voltage from the driving power source, and the protection circuit 14 arranged between the amplifier circuit and the load. In the amplifier, a protection circuit operation notification system for the power supply amplifier limits the current flowing through the load in the protection circuit to a set value when the current exceeds the set value in detecting the current flowing through the load, includes a comparator 19 for comparing an input voltage value of the amplifier circuit with a voltage value obtained by gain-converting 16 an output voltage of the protection circuit in the amplifier circuit, and detects the operation start of the protection circuit by an output of the comparator. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
