| 摘要 |
PURPOSE:To reduce variation in current output at a constant current circuit part, by switching emitter resistances of constant current source transistors (TR) constituting a switching circuit part and putting the switching circuit part in operation. CONSTITUTION:The emitter resistances of the constant current source TRs constituting the switching circuit part are switched to put the switching circuit part in operation. For example, a resistance R10 having a prescribed resistance value is connected to a switch SW1 in parallel and when the switch SW1 is turned off, PNPTRs Q1 and Q2 and an NPNTRQ6 are turned off to turn off an output terminal OUT1. Further, an NPNTRQ8 is turned on by the collector current of a PNPTRQ3 to turn on an output terminal OUT2. When the switch SW1 is turned on, the PNPTRs Q1 and Q2 and NPNTRs Q6 and Q7 are turned on to turn on the output terminal OUT1, and the NPNTRQ8 is turned off to turn off the output terminal OUT2. |
