| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a current control circuit with a limiter eliminating dispersion of limiter voltage caused by temperature characteristics by maintaining highly accurate control. <P>SOLUTION: The current control circuit with the limiter has a transistor 5 with a source follower configuration, an operational amplifier 1 using an input voltage Vi as a positive-phase-sequence input, and an output of the transistor 5 as a negative-phase-sequence input, an operational amplifier 3 using a reference voltage Vr serving as the limiter voltage as a positive-phase-sequence input, and the output of the transistor 5 as a negative-phase-sequence input, and diodes 2 and 4 connecting each output of the operational amplifiers 1 and 3 to an input of the transistor 5. If Vi<Vr, the diode 2 is turned on, the diode 4 is turned off, and a current proportional to Vi is supplied to a load R1 of an emitter output of the transistor 5. In cases other than Vi<Vr, the diode 4 is turned on, the diode 2 is turned off, the emitter output of the transistor 5 is fixed at Vr, and a constant current is supplied to the load R1. Since Vf of the diodes and Vbe of the transistor are included in feedback loops of the operational amplifiers, there are no effects to their temperature characteristics. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
