Title:
SWITCHED CAPACITOR TYPE D/A CONVERTER AND DISPLAY DRIVING CIRCUIT
Document Type and Number:
Japanese Patent JP3216604
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To obtain a switched capacitor type D/A converter which can shorten a reset period without increasing a circuit scale by providing a voltage source and a switch for forcibly setting the output of an operational amplifier to a specific voltage at the beginning of a reset mode.
SOLUTION: This converter has level voltages V1 and V2, a reference voltage Vr, and an external driving voltage Vex as analog inputs. Further, switches SW1 to SW6 are provided which switch the operation of the switched capacitor type D/A converter. The level voltages V1 and V2 prescribe the voltage range of voltages that the switched capacitor type D/A converter can output according to input digital data. The reference voltage Vr is outputted after being amplified according to the amplification degree determined by the capacity value ratio of an output capacity value Cc and the sum of input capacity values C0 to Cn. The external driving voltage Vex operates the operational amplifier forcibly at a high speed. The switch SW6 controls the connection of the external driving voltage Vex.
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Inventors:
Katsumi Abe
Application Number:
JP17921398A
Publication Date:
October 09, 2001
Filing Date:
June 25, 1998
Export Citation:
Assignee:
NEC
International Classes:
G09G3/36; G09G3/20; H03H19/00; H03M1/10; H03M1/66; H03M1/74; H03M1/80; (IPC1-7): H03M1/66; G09G3/20; G09G3/36; H03H19/00; H03M1/74
Domestic Patent References:
| JP8125502A |
Attorney, Agent or Firm:
Johei Yamashita