| 摘要 |
PROBLEM TO BE SOLVED: To obtain a desired voltage without depending upon the multiplication factor of voltage boosting of a boosting circuit and also to efficiently use a capacitor which is not used in a voltage boosting. SOLUTION: The output voltage Vpr of a boosting circuit 24 is divided by resistors R5 and R6. The difference voltage between the divided voltage Vback and a reference voltage Vref is amplified by an operational amplifier 23 to be fed back to the boosting circuit 24 and it is voltage boosted. Thus, a desired stabilized output voltage Vpr is obtained by repeating such an operation. The output voltage Vpr obtained in this manner is divided into driving voltages V0 to V4 by a voltage dividing circuit 22 and they are supplied to a row driver and a column driver. Moreover, the connection of a voltage boosting capacitor Cpr which does not contribute to the voltage boosting is changed over to a connection between the output potential of the circuit 24 and the ground potential and the capacitor Cpr is used as a stabilizing capacitor Cst or it is used as an auxiliary capacitor by being connected in parallel with another voltage boosting capacitor.
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