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A digital-to-analog converter gain self-calibration circuit

A digital analog, self-calibration technology, applied in digital-to-analog converter, analog/digital conversion calibration/test, analog/digital conversion, etc., can solve problems such as long calibration time

Active Publication Date: 2021-02-12
SHANGHAI HUAHONG INTEGRATED CIRCUIT +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The current method of DAC gain calibration is to calibrate each frequency point separately, and the calibration time is very long

Method used

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  • A digital-to-analog converter gain self-calibration circuit

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Effect test

Embodiment Construction

[0016] figure 1 It is a functional block diagram of an embodiment of the DAC gain self-calibration circuit, including:

[0017] The first counter 1 counts the XTAL output clock to control the DAC gain self-calibration process. The counter has five output signals, which are output signal HF_WAIT, output signal HF, output signal LF_WAIT, output signal LF, and output signal COMP.

[0018] When the VCO is calibrated to a fixed frequency point, if the DAC gain self-calibration is enabled, the output signal HF_WAIT is 1, the output signals HF, LF_WAIT, LF, and COMP are 0, and the counter starts to count the input clock. When the count value is the first preset value, the counter is cleared, and the input clock is counted again, the output signal HF is 1, and HF_WAIT, LF_WAIT, LF, COMP are 0. When the count value reaches the second preset value, the counter is cleared, and the input clock is accumulated and counted again, the output signal LF_WAIT is 1, and HF_WAIT, HF, LF_WAIT, CO...

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Abstract

The invention discloses a digital-to-analog converter (DAC for short) gain self-calibration circuit, comprising: a first counter counts the output clock of the crystal oscillator (XTAL for short), and controls the state jump of the DAC gain calibration circuit; the DAC control circuit outputs the DAC The frequency division circuit completes the frequency division of the voltage-controlled oscillator (VCO) output clock; the second counter completes the counting of the frequency division circuit output clock; the first lookup table outputs the preset frequency point corresponding to the DAC gain control word ; The second lookup table outputs the difference between the DAC gain control word at the target frequency point and the center frequency point; the fine-tuning control circuit outputs the DAC gain control word at the target frequency point. The present invention can change the capacitance value of the varactor in the inductor-capacitor oscillator by calibrating the DAC gain, finally change the frequency tuning curve of the VCO, and obtain the target frequency signal, and can also automatically Complete quick calibration of DAC gain for multiple frequency tuning curves.

Description

technical field [0001] The invention relates to a digital-to-analog converter (hereinafter referred to as DAC) gain self-calibration circuit, which is mainly applied to fast self-calibration of DAC gain in one or more frequency tuning curves in a direct modulation system in FSK modulation communication. Background technique [0002] The direct modulation method is a commonly used modulation method for frequency shift keying modulation. In the direct modulation method, in order to obtain the modulation signal near the carrier that meets the requirements, there are certain requirements for the amplitude of the DAC output signal. [0003] The current DAC gain calibration method is to calibrate each frequency point separately, and the calibration time is very long. Contents of the invention [0004] The technical problem to be solved by the present invention is to provide a DAC gain self-calibration circuit, which can calculate the DAC gain control words of all frequency point...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H03M1/10H03M1/66
CPCH03M1/1019H03M1/66
Inventor 周亚莉衣晓峰
Owner SHANGHAI HUAHONG INTEGRATED CIRCUIT
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