A High Stability Flyback DC-DC Converter

Abstract

The invention discloses a high-stability flyback direct current-direct current (DC-DC) converter. According to the converter, a voltage feedback loop and a current feedback loop are adopted in flyback topology, so that the transient response of a converter device is accelerated. A novel frequency compensation circuit is also adopted. The frequency compensation circuit mainly comprises an error amplifier, a Miller capacitance control unit and a dynamic zero control unit. According to the Miller capacitance control unit, a large compensation capacitor in the traditional dominant pole compensation can be replaced by a small compensation capacitor, so that the area is saved, and the transient response of the system is improved. According to the dynamic zero control unit, the introduced zero point can well offset the first non-dominant pole of the system under the condition that the output has fluctuation, and the stability of the system is guaranteed. According to the DC-DC converter, a compensation resistor and a compensation capacitor can be integrated to a chip, internal compensation is realized, and the area of the chip is saved; meanwhile, the circuit structure is simple, the reliability is high, the phase margin can be 90 degrees, and the stability of the system is high.

Description

technical field [0001] The invention belongs to the technical field of switching power supplies, in particular to a high-stability flyback DC-DC converter. Background technique [0002] In portable electronic products, each part of the system has different requirements for working power, and the power supply of each part is generally supplied separately, so that the independence of each part can be kept to the greatest extent possible. The flyback (Fly-back) switching power supply structure is widely used in portable electronic products, mainly because the structure of the flyback switching power supply is simple, and the few devices used can save a lot of cost. At the same time, more importantly, the flyback switch The power supply is easy to achieve multiple outputs, so that a variety of different power supply outputs can be realized through a flyback switching power supply control circuit, which can also reduce the complexity of the circuit, reduce the space of the power ...

AI Technical Summary

Problems solved by technology

while V a The change is through the large compensation capacitor C at the output of the error amplifier c The charge and discharge to achieve, obviously a large compensation capacitor C c directly reduces the V a changes, so the dynamic response speed of the system is very slow

In addition, large compensation capacitors cannot be integrated, which increases the area of ​​the entire circuit

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