US 7,583,217 B2 · Switched capacitor type D/A converter, and drive circuit for liquid crystal display

Abstract

A D/A converter of switched capacitor type capable of shortening the time for D/A conversion process without increasing power consumption is provided. The D/A converter comprises capacitors Cx and Cy for receiving input voltage corresponding to the digital data and charging the amount of charge corresponding to the input voltage, and an operational amplifier A21 including a first amplified output terminal To1 and a second amplified output terminal To2 for individually outputting amplified signals generated based on a signal inputted to the input terminal. During the conversion process, the amplified signal is outputted from the first amplified output terminal To1, after the conversion process is completed, the amplified signal is outputted through an output switch Sw6 from the first amplified output terminal To2.

Claims8

Dependent claims

A D/A converter of switched capacitor type comprising:

a capacitor that is given input voltage corresponding to digital data to be converted, and charges an amount of charge corresponding to the input voltage;
and
an operational amplifier including an input terminal receiving converted voltage based on the amount of charge charged into the capacitor, and an output terminal for outputting an amplified signal generated based on a signal inputted to the input terminal;
wherein
the operational amplifier comprises first and second amplified output terminals each of which can be controlled independently, wherein
the operational amplifier comprises a first switching transistor for controlling whether or not to output the amplified signal from the first amplified output terminal, and a second switching transistor for controlling whether or not to output the amplified signal from the second amplified output terminal.

3 more elements

A D/A converter of switched capacitor type comprising:

a capacitor that is given input voltage corresponding to digital data to be converted, and charges an amount of charge corresponding to the input voltage;
and
an operational amplifier including an input terminal receiving converted voltage based on the amount of charge charged into the capacitor, and an output terminal for outputting an amplified signal generated based on a signal inputted to the input terminal;
wherein
the operational amplifier comprises first and second amplified output terminals each of which can be controlled independently, wherein
the operational amplifier outputs the amplified signal from the first amplified output terminal after a conversion process for the digital data is started until all of the input voltage corresponding to the digital data is applied to the capacitor, and outputs the amplified signal from the second amplified output terminal after application of all of the input voltage corresponding to the digital data has been completed.

3 more elements

Dependencies are inferred from the claim text.

Switched capacitor type D/A converter, and drive circuit for liquid crystal display

Life of this patent

Switched capacitor type D/A converter, and drive circuit for liquid crystal display

Life of this patent

Abstract

Claims8