| 摘要 |
<P>PROBLEM TO BE SOLVED: To prevent an input current from flowing for more than a necessary amount when CTR of an optical semiconductor such as a photocoupler does not deteriorate. <P>SOLUTION: A driving circuit of an optical semiconductor for switching the photocoupler and the like and transmitting a pulse signal includes: a switch for varying input resistance; and an output current determining section for monitoring an output current and turning on/off the switch. The deterioration of CTR is determined by a value of the output current and an input resistance value is made appropriate. Thus, only the necessary input current is allowed to flow. Even if the CTR of the photocoupler does not deteriorate, the input current can be prevented from flowing for more than the necessary amount. <P>COPYRIGHT: (C)2013,JPO&INPIT |
