JPS6438794A - Piezo-electric buzzer driving circuit - Google Patents

Abstract

PURPOSE: To prevent the lowering of the life of a battery by outputting a continuous pulse voltage at the time of driving a piezoelectric buzzer, changing the state to a floating state at the time of stopping the piezoelectric buzzer and depressing power decrease due to a leakage current in the piezoelectric buzzer or about the packaging part of the piezoelectric buzzer. CONSTITUTION: At the time of stopping the piezoelectric buzzer, a signal 101 becomes a low level and a signal 103 becomes a high level by means of an inverter 15. Thus, since a gate 6 inputs the low-level signal 101, it outputs a high level, a gate 7 inputs the high-level signal 103, it outputs a low level, a P-channel field effect transistor 10 and a N-channel field effect transistor 11 are turned off together and a terminal 4 becomes a floating state. Similarly, a gate 8 inputs the low-level signal 101 and outputs a high level, a gate 9 inputs the high-level signal 103 and outputs a low level, a P-channel field effect transistor 12 and a N-channel field effect transistor 13 are turned off together and a terminal 5 becomes a floating state. Consequently, the leakage current and the lowering of the life are prevented.