Method for calibrating analog-to-digital converter

A method for calibrating an analog-to-digital converter, comprising the following steps:

• conducting an initial performance test and judgement on an analog-to-digital converter;
• if the initial performance test of the analog-to-digital converter succeeds, performing a pre-trimming and judgement on the analog-to-digital converter;
• if the pre-trimming of the analog-to-digital converter succeeds, performing an error extraction on the analog-to-digital converter and obtain errors of conversion stages thereof;
• performing an error soft trimming and test on the analog-to-digital converter according to the errors of the conversion stages;
• and
• if the error soft trimming and test of the analog-to-digital converter succeed, performing an error hard trimming and test on the analog-to-digital converter according to the errors of the conversion stages;
• wherein the step of performing the initial performance test and judgement on the analog-to-digital converter comprises:
• configuring a handshake signal;
• conducting an initial performance test on the analog-to-digital converter and collect initial testing output data of the analog-to-digital converter;
• judging whether the initial testing output data is/are normal;
• if the initial testing output data is/are normal, calculating a characteristic parameter of the analog-to-digital converter according to the initial testing output data;
• and
• judging whether the characteristic parameter reaches a threshold, wherein if the characteristic parameter reaches the threshold, the initial performance test of the analog-to-digital converter succeeds;
• wherein the analog-to-digital converter comprises N conversion stages, and the step of performing the pre-trimming and judgement on the analog-to-digital converter comprises:
• extracting weight errors of previous M conversion stages under a constraint of a minimum mean square error;
• extracting gain errors of the previous M conversion stages under the constraint of the minimum mean square error;
• calibrating the analog-to-digital converter according to the weight errors and the gain errors of the previous M conversion stages;
• conducting a performance test on the calibrated analog-to-digital converter and collect a testing output of the analog-to-digital converter;
• and
• judging whether the pre-trimming of the analog-to-digital converter succeeds according to the testing output thereof,
• wherein N is an integer greater than or equal to 2, and M is an integer of 1 to N-1;
• wherein the step of performing the error extraction on the analog-to-digital converter and obtain errors of the conversion stages of the analog-to-digital converter comprises:
• for each conversion stage, configuring the input signal and an output mode according to a quantity of errors that need to be tested;
• for each conversion stage, performing an analog-to-digital conversion by using the analog-to-digital converter according to the configured input signal and the configured output mode, collecting output data of the analog-to-digital converter, restoring the output data according to a characteristic of the input signal, and obtaining ideal output data;
• and
• for each conversion stage, extracting errors of the conversion stage from a difference between the output data and the ideal output data by using an adaptive parameter extraction method;
• wherein the step of performing the error soft trimming and test on the analog-to-digital converter according to the errors of the conversion stages comprises:
• sending the errors of the conversion stages to a temporary storage register of the analog-to-digital converter for storage;
• calibrating the analog-to-digital converter according to the errors stored in the temporary storage register, and complete the error soft trimming of the analog-to-digital converter;
• performing an analog-to-digital conversion test on the analog-to-digital converter after the error soft trimming, obtaining soft trimming testing output data, and calculating a characteristic parameter of the analog-to-digital converter after the error soft trimming according to the soft trimming testing output data;
• and
• judging whether the error soft trimming of the analog-to-digital converter succeeds according to the characteristic parameter thereof after the error soft trimming;
• wherein the step of performing the error hard trimming and test on the analog-to-digital converter according to the errors of the conversion stages comprises:
• writing the errors of the conversion stages stored in the temporary storage register into an internal built-in memory of the analog-to-digital converter for permanent storage;
• automatically reading the errors stored in the internal built-in memory during each power-on, calibrating the analog-to-digital converter through the errors, and completing the error hard trimming thereof;
• performing an analog-to-digital conversion test on the analog-to-digital converter after the error hard trimming, obtaining hard trimming testing output data, and calculating a characteristic parameter of the analog-to-digital converter after the error hard trimming according to the hard trimming testing output data;
• and
• judging whether the error hard trimming of the analog-to-digital converter succeeds according to the characteristic parameter thereof after the error hard trimming.