定電流駆動回路

Japanese Patent JP4125723

B2

A constant current driving circuit for supplying a constant current to a load circuit includes: a first driver circuit having a pulse width converting circuit for converting a first difference detection signal into a pulse signal having a pulse width corresponding to a signal level of the first difference detection signal, a switch turned on/off on a basis of the pulse signal, and a smoothing circuit for supplying a smoothed first load current to the load circuit; a first current detecting circuit for converting the first load current into a first voltage corresponding to the first load current, and outputting a first current detection signal; a second driver circuit for supplying a second load current to the load circuit on a basis of a signal level of a second difference detection signal; a second current detecting circuit for converting the second load current into a second voltage corresponding to the second load current, and outputting a second current detection signal; a first difference detecting circuit for calculating the first difference detection signal to make zero a difference between the first current detection signal and an input voltage; a second difference detecting circuit for detecting a difference voltage between the first current detection signal and the input voltage, and outputting a third difference detection signal; and a third difference detecting circuit for detecting a difference voltage between the third difference detection signal and the second current detection signal, and outputting the second difference detection signal.

Yuji Tamura
Tomoyuki Otsuka

JP2004569103A

July 30, 2008

March 06, 2003

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富士通株式会社

G05F1/56; H02M3/155; H03K7/08

JP11075364A
JP2000089837A
JP6168043A
JP4130506A

US5422562

Akira Matsumoto

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