An improved voltage marking D/A converter

Abstract

The invention relates to a circuit, in particular to an improved voltage calibration digital-to-analog converter, which is mainly used in universal serial bus (USB) earphones, microphones, telephones and other audio systems. According to the technical proposal provided in the invention, in a series-parallel combined resistor network, the voltage is divided into a coarse tuning resistor network and a fine tuning resistor network, the output terminal of the coarse tuning resistor network is connected with the positive pole terminal of an operation amplifier, the output terminal of the fine tuning resistor network is connected with the negative pole terminal of the operation amplifier, a quantitative switch is respectively provided on each resistor in the coarse tuning resistor network and fine tuning resistor network, and a correction resistor is connected in the fine tuning resistor network in parallel; and during operation, a binary data to be converted is firstly inputted and separated into high-order data and low-order data, and the middle and low-order data is decoded and used for controlling the quantitative switch in the fine tuning resistor network. The invention reduces the number of resistors, so as to reduce the product cost and improve the conversion accuracy of the product.

Description

technical field [0001] The invention relates to a circuit, in particular to an improved voltage calibration digital-to-analog converter, which is mainly used in audio systems such as Universal Serial Bus (USB) earphones, microphones and telephones. Background technique [0002] The traditional simple voltage scaling digital-to-analog conversion (DAC) is achieved by using 2 n A resistor string consisting of two resistors will V ref Divide into equal 2 n segment, such as figure 2 As shown, thus achieving inherent monotonicity. Each set of binary switch tree selections corresponds to a given input data bit. Another advantage is that if the voltage value V connected to the top and bottom nodes of the resistor string h and V l is an arbitrary value, the DAC will be at V h and V l There are 2 n The resolution of quantization steps is interpolated. But the maximum number of resistors (2 n ) and the number of switches (2 n+1 -2) The actual potentiometer DAC is limited to...

AI Technical Summary

Problems solved by technology

But the maximum number of resistors (2 n ) and the number of switches (2 n+1 -2) The actual potential measurement DAC is limited to the range of n≤8, which is mainly limited by the large area of ​​the resistor, the relative accuracy of the resistor is not easy to control, and the effective performance of the electronic switch does not meet the design requirements

Thus affecting the conversion accuracy of the DAC

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