| 摘要 |
A source driver 1 according to the present invention is comprised of a bias circuit 3 and an output circuit 2. In the output circuit 2, a differential unit 21 amplifies the difference between two input signals received through input terminals IN1 and IN2. An output unit 22 made up of the transistors Q5, Q8, and Q9, and a capacitor C, receives a signal from the differential unit 21, amplifies it, outputting it to a liquid crystal display (not shown) via a variable-resistance unit 25 with analog switches S1 and S2. A selection circuit 26 causes each of the analog switchs S1 and S2 to be activated or deactivated. A bias current circuit 23 changes a current flowing through a differential amplification circuit made up of the transistors Q1 to Q4. A bias current changing circuit 24 changes a bias current flowing through a circuit made up of a transistor Q5 and a capacitor C. A bias circuit 3 receives an external voltage V, exerting a control of the bias current flowing through respective bias current changing circuits 23 and 24. A bias voltage selection circuit 32 changes a bias voltage output from the bias unit 31, and then sends it to the bias current changing circuits 23 and 24.
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