| 摘要 |
PURPOSE: An active drive device is provided to form a control device for controlling easily brightness and a grey level of a display device by using a pulse width modulation method and a circuit control method. CONSTITUTION: A capacitor(Cch) for storing charges is connected with a positive supply voltages(Vdd). A drive transistors(Q2) drives a display device(OEL) by applying the charges stored in the capacitor(Cch) to the display device(OEL). A switching transistor(Q3) switches a data line signal by using a scan line signal. A pulse modulation portion(10) controls a drive time of the drive transistors(Q2) by controlling pulse widths of a data line and a scan line. The positive supply voltage(Vdd) is connected with the drive transistors(Q2). The capacitor(Cch) is connected between the positive supply voltage(Vdd) and the drive transistors(Q2). The drive transistors(Q2) are connected with the display device(OEL). One terminal of the display device(OEL) is connected with a negative supply voltage(Vss). A voltage protection diode(D1) is connected parallel between the drive transistor(Q2( and the display device(OEL).
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