| 摘要 |
PURPOSE: To obtain a gamma conversion circuit with a high product yield, which is characterized by means of a gamma conversion curve having a free gain, by connecting a plurality of variable gain circuits in parallel, which are provided with a differential amplifier circuit where the gain of an output voltage is changed in accordance with a difference between two input voltages which are inputted from the outside. CONSTITUTION: This variable gain circuits (voltage-controlled amplifiers: VCA circuits) are connected in multistage manner, by which the gain of the output voltage can be changed arbitrarily by setting a voltage from the outer part, in the part of the gamma conversion circuit 5 in a display device. That is, a plurality of VCA circuit blocks VCA1 to VCA3 are connected in parallel in the circuit 5. The VCA circuit blocks (VCA1 to VCA3) cover the fixed range of the voltage of an input Vin and the gain can be arbitrarily changed by the gain setting voltages VG1 to VG3 from the outer part. Therefore, the gamma conversion curve is freely set by a straight line approximation.
|
