Monitoring device and method of ESR and L of Buck DC/DC converter

Abstract

The invention provides a monitoring device and method of ESR (equivalent series resistor) and L (inductance) of a Buck DC / DC converter. The monitoring device comprises a Buck open-loop circuit, a capacitor switching circuit, a PWM wave-shaping circuit, a ripple isolation amplifying circuit, a signal processing module and a display module. The method comprises the steps that a switching frequency,a duty ratio and an output voltage ripple before capacitor parallel connection to an output end are calculated; a shunt capacitor is connected to the output end of the Buck converter in parallel, anda switching frequency, a duty ratio and an output voltage ripple after capacitor parallel connection are calculated; the switching frequencies, the duty ratios and the output voltage ripples are sentinto the signal processing module for comprehensive processing, and values of the ESR and L of an output filter capacitor of the Buck converter are obtained and displayed in real time.

Description

technical field [0001] The invention relates to a monitoring technology in electric energy conversion, in particular to a monitoring device and method for ESR and L of a step-down DC / DC converter. Background technique [0002] Due to the advantages of high efficiency and small size, switching power supplies are widely used in daily production and life. Generally speaking, in order to obtain a relatively stable output voltage, capacitors must be used to effectively filter out high-frequency noise. After the switching power converter works for a period of time, the capacitance (Capacitance, C) and equivalent series resistance (Equivalent Series Resistance, ESR) of the capacitor will change. Compared with the initial capacitance C and resistance ESR, when the change is relatively small When it is large, it can be considered that the capacitor has failed, and the failure of the capacitor will cause the operation failure of the power supply and the system. [0003] Buck, Boost,...

AI Technical Summary

Problems solved by technology

Off-line monitoring calculates capacitance parameters by adding an excitation signal to both ends of the capacitor under test and measuring the resulting response. It has the advantages of simplicity and reliability, but this method requires the equipment to be shut down, and sometimes even the capacitor under test needs to be removed. Therefore, This method is not practical

Compared with offline monitoring, online / quasi-online monitoring can calculate capacitance parameters by adding sensors to measure voltage, current and other information when the capacitor is working under the condition of normal operation of the circuit. This method can accurately and real-time monitor The capacitor is working, but its cost is too high, and the added sensor will destroy the original structure of the circuit and affect the performance of the circuit

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