Fixed-frequency dual-mode synchronous step-down controller

Abstract

The invention relates to a fixed-frequency dual-mode synchronous step-down controller and belongs to the integrated circuit technology. The controller comprises a switch-on time circuit, a comparator, a digital logic circuit, a switch selection circuit and a transconductance amplifier; the output end of the switch-on time circuit is connected to the first input end of the digital logic circuit; the output end of the comparator is connected to the second input end of the digital logic circuit; the digital logic circuit is provided with two output ends and is used for controlling the level states of the two output ends according to the level of the first input end and controlling the level states of the two output ends according to the level of the second input end; and the positive input end of the transconductance amplifier is connected with a second reference voltage end, and the negative input end of the transconductance amplifier is connected with a feedback voltage end. According to the fixed-frequency dual-mode synchronous step-down controller of the invention, the conversion frequency is a fixed value, the condition that the conversion frequency of a traditional hysteresis control mode is influenced by other parameters such as ESR, inductance L and the like can be avoided, the EMI interference is effectively reduced, and the reliability and stability of equipment in a system can be effectively improved.

Description

technical field [0001] The present invention relates to integrated circuit technology. Background technique [0002] The synchronous buck controller with fixed conversion frequency dual control mode function is a very important part in power management applications, mainly used in many environments such as set-top boxes, notebook computers, mobile power systems, and linear regulator power supplies. It has the advantages of small size, low cost, convenient application, strong anti-interference ability, etc., so it is widely used. [0003] In a portable application environment, the operating frequency of a mobile communication device can reach a range of hundreds of KHz to tens of MHz. In this wide bandwidth range, noise will affect the stability of the normal operation of electronic equipment and reduce the communication quality of communication equipment. This requires the DC-DC converter to have a fixed conversion frequency, reduce EMI interference, and improve the stabil...

AI Technical Summary

Problems solved by technology

This will bring EMI interference signals to other devices in the PCB board, and ultimately affect the reliability and stability of the system

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