| 摘要 |
PURPOSE:To eliminate a transformer, etc., and to miniaturize a circuit by outputting the output of a positive side DC/DC converter during the one half cycle of a ringing cycle and outputting the output of a negative side DC/DC converter during the other half cycle of the ringing cycle. CONSTITUTION:The signal of an oscillator 14 to generate the signal of a call signal frequency is received and the output voltages of a positive side DC/DC converter 10 and a negative side DC/DC converter 12 are mutually outputted from a switch circuit 16. Thus, since a circuit is composed of the composing element of a small size only, the circuit can be miniaturized and a sharing to the circuit is not requested. Moreover, a setting in a line correspondence or in several lines correspondence comes to be possible, even a load dispersion is obtained and also the reliability of a system is improved. Low power consumption and a lowered noise can be obtained, too.
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