| 摘要 |
A current switching circuit has a setting section, a switching section and a switch changeover section. The switching section has a current mirror circuit, n switching transistors, and a compensating circuit. The current mirror circuit has first through third transistors. Emitters of the first and second transistors are connected to a power supply terminal and bases thereof are connected with each other. The third transistor has an emitter connected to the bases of the first and second transistors, a collector grounded, and a base connected to a collector of the first transistor. The switching transistors have emitters connected to the collector of the second transistor, and collectors connected to one terminals of n load elements. The other terminals of the load elements are grounded. The switch changeover section controls the base currents of the switching transistors. The compensating circuit comprises two compensating transistors. The first compensating transistor has an emitter and a base connected to an emitter and a base of the second transistor, respectively. The first compensating transistor has a same size as that of the second transistor. The second compensating transistor has an emitter connected to a collector of the first compensating transistor, a collector grounded, and a base connected to the collector of the second transistor. The second compensating transistor has a same size as that of each of the n switching transistors.
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