Faulty operation prevention circuit especially for setting apparatus in cordless telephone

摘要

The circuit prevents a faulty operation by disconnecting the current supply when an unstable current supply is fed to a setting apparatus of a cordless telephone in order to provide an operating voltage using a rectifier without using a battery. The circuit includes a divider to divide a voltage output from the rectifier unit to an adapted voltage level so as to output the divided voltage. The circuit also has a voltage control unit. This controls the operating voltage fed to the setting apparatus depending on the divided voltage that is output from the voltage divider. The voltage control unit may include a first transistor into which the divided voltage is input, to switch it on and off. It may also have a second transistor to control the operating voltage according to the switching on and off of the first transistor. The base of the second transistor is connected to the collector of the first.