| 摘要 |
PURPOSE:To attain high speed switching for a constant current to a load circuit by supplying a current from a constant current source to the load circuit turned on/off by a high and low level of an input signal, and a pseudo load circuit equivalent thereto via a current mirror circuit. CONSTITUTION:A current mirror circuit 10 is provided with current supplying terminals 14, 15 and corresponding current flowing-out terminals 16, 17. The current I1 flow the terminal 17 flows a resistor 13 and fed to a drive input terminal 8. When a pulse input voltage VIN is applied to the input terminal 5, the input circuit 1 outputs an output voltage V01. When the voltage V01 is at a high level, the current I1 is made flow to the load circuit 4 as the current I0 and when low level, the current flows to the input circuit 1 via a diode 2 as the current Iin. The current from an output terminal 16 is fed to a pseudo load circuit 11 equivalent to the load circuit 4 via the resistor 12. Thus, the effect of a floating capacitor 9 onto the leading of the load drive voltage is eliminated and the current to the load circuit 4 is switched at a high speed. |
