Constant current starting circuit applied to boost converter

Abstract

The invention discloses a constant current starting circuit applied to a boost converter, and belongs to the technical field of the electronic. The constant current starting circuit comprises a power level, a constant current starting module, a bias circuit module and an enabling module, wherein the bias circuit module is used for producing the constant first bias current and second bias current to provide for the constant current starting module; the enabling module is used for producing an enabling signal EN to control the on and off of the bias circuit module and the constant current starting module; the constant current starting module is used for limiting the power-level charging current as a fixed value by using a current mirror and the constant bias current. By clamping the charging current, namely the inductive current as the fixed value, the constant current charging at the soft starting stage is realized, and the surge current at the circuit starting stage of the boost converter is eliminated.

Description

technical field [0001] The invention belongs to the field of electronic technology, and in particular relates to the design of a constant current starting circuit applied to a Boost (boost converter) converter. Background technique [0002] Boost converters are widely used in electronic computers, various electronic terminal equipment, and communication equipment due to their small size, light weight and high efficiency. [0003] A typical Boost converter architecture such as figure 1 As shown, mainly by the switching power tube M N , M P , energy storage inductor L, output capacitor C out , load R load composition. The basic working principle is: using the energy storage characteristics of inductance and capacitance, in the switch tube M N Conduction, M P When turned off, the current passes through the inductor and is converted into magnetic energy and stored in the inductor; M N off, M P When turned on, the inductor passes through M P Discharge, transfer the stor...

AI Technical Summary

Problems solved by technology

[0006] When starting, if the output voltage is too low, the input and output pressure difference will be large, and the rising slope of the inductor current will be very large, which will cause a large surge current during starting, which may damage the switch tube M P , energy storage inductor L or other devices, resulting in abnormal operation of the circuit system

In addition, in practical applications, the Boost converter is usually directly connected to the battery of a portable electronic device. Due to the internal resistance and heat generation of the battery, the instantaneous surge current may cause the battery to burn out.

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