Clock duty ratio calibration circuit and clock duty ratio calibration method

Abstract

The embodiment of the invention provides a clock duty ratio calibration circuit and calibration method, and the circuit comprises a transmission circuit for receiving an input clock signal and sendingan output clock signal, wherein the transmission circuit is provided with a first node and a second node; a first pull-up circuit which is connected to the first node and charges the first node; a second pull-up circuit which is connected to a second node and charges the second node; a first pull-up current adjusting circuit which is connected with the first pull-up circuit, wherein the chargingrate of the first pull-up circuit to the first node is changed by changing the pull-up current of the first node so as to adjust the duty ratio of the output clock signal; and a second pull-up currentadjusting circuit which is connected with the second pull-up circuit, wherein the charging rate of the second pull-up circuit to the second node is changed by changing the pull-up current of the second node so as to adjust the duty ratio of the output clock signal. According to the embodiment of the invention, different nodes on the transmission circuit are charged, so the duty ratio of the output clock signal of the transmission circuit can be quickly and accurately adjusted to about 50%.

Description

technical field [0001] The invention relates to the field of semiconductor integrated circuits, in particular to a clock duty ratio calibration circuit and a calibration method. Background technique [0002] This section is intended to provide a background or context to embodiments of the invention that are recited in the claims. The descriptions herein are not admitted to be prior art by inclusion in this section. [0003] In the field of DRAM (Dynamic Random Access Memory, dynamic random access memory), DDR (Double Data Rate SDRAM, double-rate synchronous dynamic random access memory) technology triggers reading data on the upper and lower edges of the clock, so a good duty cycle Clocks are also more important in the DRAM world. However, the existing clock calibration circuit cannot quickly and accurately adjust the duty cycle of the clock signal, thus failing to ensure the correctness of the data read from the entire DRAM. Contents of the invention [0004] Embodimen...

AI Technical Summary

Problems solved by technology

However, the existing clock calibration circuit cannot quickly and accurately adjust the duty cycle of the clock signal, so it cannot guarantee the correctness of the data read by the entire DRAM.

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