Digital analogue converter

Abstract

The invention provides a digital analogue converter which is used for converting digital codes into output voltage and has self-correcting function. The digital analogue converter comprises a correcting signal generator, a constant current generator, a first current supplier, a second current supplier and a current voltage converter. The constant current generator generates a constant current andsplits the constant current to a first current generating element which actually acts in the first current supplier. The second current supplier comprises a plurality of second current generating elements to generate proportionable current with the first current generating element. The digital codes set the number of the second current generating elements which actually act to generate an output current which is converted into the output voltage via the current voltage converter. The correcting signal generator generates correcting signals according to the output voltage and is for regulatingthe number of the first current generating elements which actually act in the correcting mode. The digital analogue converter converts a digital code into an output voltage with self-correcting function, and enters a correcting mode to correct only during the start initial stage.

Description

technical field [0001] The present invention relates to a digital-to-analog converter (Analog to Digital Converter, ADC), in particular to a digital-to-analog converter with a self-calibration function. Background technique [0002] figure 1 It is a traditional digital-to-analog converter 100, which converts a digital code D in converted to an analog value to an output voltage V out presented. As shown, the voltage V ref Applied to the resistor R to set the current I pd ; Transistor M 1 responsible for supplying the current I pd , its gate voltage V con coupled to the transistor M 21 , M 22 …M 2n gate terminal, so that the transistor M 21 , M 22 …M 2n to generate current. According to the digital code D in , the switching circuit 102 sets the transistor M 21 , M 22 …M 2n Coupled to a current-to-voltage converter (this illustration is represented by a resistor R out Realized) situation, so that the output current I out With digital code D in Change. Sinc...

AI Technical Summary

Problems solved by technology

[0005] However, in the technology shown in US 6157332, the capacitor 220 will have leakage problems

During use, the above correction actions must be repeated periodically to maintain the voltage V ref accuracy; so the technology shown in US 6157332 can only be applied to electronic devices with synchronization intervals, such as video devices

In addition, the charge pump 218 and the selective output signal coupler (selective output signal coupler) 222 will increase the complexity of the circuit and increase the cost of the circuit

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