| 摘要 |
<p>PURPOSE:To prevent the generation of noise, in a printer due to an electrophotographic system, by providing an integrator for generating integral output voltage, a differential amplifier with reference voltage and a current mirror circuit. CONSTITUTION:An FET 2 consisting of a P-channel MOS to which voltage is applied from a voltage applying source 1 constitutes a current mirror circuit CM along with FETs 4, 6 and the output current I1 or In equal to the current I0 flowing to the FET 2 is supplied to a load 7 being an LED array by the FETs 4, 6. A drive signal B for controlling the driving time of the load 7 becomes a triangular wave or trapezoidal integral output voltage from an integrator 11 and outputs the output voltage corresponding to the difference with reference voltage due to a resistor 9 from a differential amplifier 10 to control the gate potential, that is, output current I0 of the FET 2 through an FET 8. By this method, even when all of (n) bits are driven with respect to the load, di/dt becomes small and the generation of noise can be prevented.</p> |
