Flying capacitor pre-charging circuit

Abstract

The invention belongs to the field of integrated circuits and the technical field of switching power supplies, and particularly relates to a flying capacitor pre-charging circuit. The problem of pre-charging the flying capacitor of the DC-DC hybrid converter topology is solved, whether the voltage of the flying capacitor is charged to an expected value or not can be judged, the marking signal is output after the voltage of the flying capacitor is charged to a target value, charging of the flying capacitor is stopped, and power consumption is saved. A circuit for judging that charging is completed can also form a hysteresis comparator structure, so that signal mistaken overturning caused by voltage change of a flying capacitor is avoided, and noise immunity is improved. The disclosed circuit is suitable for use in a hybrid converter topology.

Description

technical field [0001] The invention belongs to the field of integrated circuits and the technical field of switching power supplies, in particular to a flying capacitor precharging circuit. Background technique [0002] With the continuous progress and development of science and technology, portable electronic devices have been widely popularized, and typical wearable devices or portable devices use lithium-ion batteries. The power management system converts the battery voltage into a plurality of stable voltages through the basic voltage conversion module to supply power for the display module, interface circuit, analog circuit and digital circuit of the portable device. As one of the basic voltage conversion modules, inductive DC-DC converters are widely used due to their high conversion efficiency, support for buck-boost and support for high output power. Typical inductive DC-DC converters include BUCK converters and BOOST converters. Limited by topology, these two tra...

AI Technical Summary

Problems solved by technology

Limited by the topology, these two traditional inductive DC-DC converters have the following disadvantages in practical applications: limited transformation ratio, large output voltage ripple and high DCR loss, and adjusting the control mode of the converter cannot solve the problem well. The above problems, so the study of new converter topology has become the key to solve the problem

[0003]Although the addition of flying capacitors can bring about many improvements, the converter topology also becomes more complex: traditional BUCK and BOOST converters only need to complete the The start-up of the sub-module served by the converter; in the hybrid converter, due to the existence of the flying capacitor voltage drop, it is additionally necessary to charge the flying capacitor, and the required voltage drop on the flying capacitor is usually different due to different hybrid topologies. Insufficient voltage drop of the flying capacitor often makes the actual working effect of the hybrid converter different from the theoretical analysis

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