Calibration system and method suitable for current source array in multichannel sectional type current steering DAC (digital to analog converter)

Abstract

The invention discloses a calibration system and a calibration method suitable for a current source array in a multichannel sectional type current steering DAC (digital to analog converter). The calibration method suitable for the current source array in the multichannel sectional type current steering DAC includes steps: firstly, calibrating a channel, and then sequentially calibrating other channels, and enabling output among all the channels to tend to be uniform, wherein when the channels are calibrated, switches in a current source switch array are by selectively closed and calibrated, and an output amplitude adjustment circuit is adjusted so as to sequentially calibrate a low data bit segment and a high data bit segment of the current source array segment by segment. The calibration method suitable for the current source array in the multichannel sectional type current steering DAC can calibrate each current source at the low data bit segment of the sectional type current steering DAC, and thereby achieves high calibration accuracy, remedies deviation and a mismatch, among the current sources in the current source array of the sectional type current steering DAC, improves linearity of the single DAC, and then improves performance indexes such as the significant number of digits of the DAC and a spurious free dynamic range, and improves linear performance of the multichannel sectional type current steering DAC and amplitude consistency among all the channels.

Description

technical field [0001] The invention relates to a current source calibration circuit and method, in particular to a calibration system and method suitable for a current source array in a multi-channel segmented current steering digital-to-analog converter. Background technique [0002] Segmented current steering DAC usually includes five parts: encoder circuit, latch array, switch array, current source array, and output amplitude adjustment circuit. The input data is encoded in the encoder circuit by segment encoding. Binary encoding is adopted, and the high-order input data is encoded by a thermometer; the encoded data is synchronized and buffered in the latch array to control the DAC switch array, and the corresponding current source in the current source array is gated by the switch; all strobed by the switch The output current of the current source is summed to obtain the current output of the entire DAC; the output current signal is finally converted into a voltage sign...

AI Technical Summary

Problems solved by technology

The patent only describes the circuit structure used for calibration and the connection method between the calibration module and the normal module, but does not disclose the specific calibration algorithm, so it is impossible to evaluate the specific accuracy that calibration can achieve

Similarly, this patent cannot be applied to the segmented current steering DAC with a channel number greater than or equal to 1 for calibration, and the consistency of output signals between channels cannot be guaranteed.

[0008] For another example, the patent application number CN201410421448 discloses a current source calibration circuit. This patent only provides a calibration method for a single current source. Although the accuracy of the current source is improved, the calibration of the current source array cannot be realized substantially. Calibration of multi-channel DAC current source arrays is not possible

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