| 摘要 |
PROBLEM TO BE SOLVED: To provide a constant current circuit capable of eliminating the possibility of the occurrence of unexpected influence on a load or a power source by a transient phenomenon in the case of the load having a large inductive component (for instance, a circuit including a coil) or the like because the rise time and the fall time of a conventional constant current circuit are below several msec in turning on/off the output current, and capable of preventing the transient phenomenon in turning on/off the output current. SOLUTION: The rise time and the fall time of current in turning on/off the current are sufficiently set long. In order to realize the rise time and the fall time in a wide range of several msec to several tens of seconds, an integrator output signal is used. Since it is difficult to stably keep a predetermined output current by the integrator output, the output of the integrator is used as a control signal for the rising part and the falling part, and a signal for keeping a predetermined current value is separately prepared. A circuit structure shown in the figure for switching the signals by a limiter is used. When the constant current circuit is used like that, adverse effect in turning on/off the current is prevented from occurring. COPYRIGHT: (C)2004,JPO&NCIPI
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