Dynamic cancellation circuit applicable to output direct-current offset of buck converter

A DC offset and dynamic elimination technology, which is applied in the direction of converting DC power input to DC power output, output power conversion devices, instruments, etc., can solve PWM comparator output jitter, slow system response speed, and decrease loop stability and other problems, to achieve the effect of enhancing system stability, simple control, and increasing precision
CN106787652AInactive Publication Date: 2017-05-31UNIV OF ELECTRONIC SCI & TECH OF CHINA
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Patent Information

Authority / Receiving Office
CN · China
Current Assignee / Owner
UNIV OF ELECTRONIC SCI & TECH OF CHINA
Publication Date
2017-05-31
Estimated Expiration
Not applicable · inactive patent

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Abstract

The invention discloses a dynamic cancellation circuit applicable to output direct-current offset of a buck converter and belongs to the technical field of electronic circuits. The dynamic cancellation circuit comprises a ripple generation circuit and a ripple superposition circuit. The dynamic cancellation circuit has the advantages that duty ratio information is added into the ripple generation circuit, voltage at a connection node SW of an upper power tube S1 and a lower power tube S2 is sampled directly to simulate to generate ripples as same as inductive current in phase, and the ripples are superposed on VFB (voltage feedback) to enable the VFB to be equal to preset VREF (voltage reference), so that a PWM (pulse-width modulation) comparator is controlled to overturn normally, system stability is enhanced, the resonance problem caused by output voltage phase lag which results from too small equivalent series resistance of an output capacitor is avoided, output voltage precision of the converter is improved, contradictions between the system stability and the precision of a valley value detection mode under traditional ripple control are overcome, and direct-current offset of output voltage can be dynamically cancelled under different application conditions, namely under different input and output voltages.
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Description

technical field

[0001] The invention belongs to the technical field of electronic circuits, and in particular relates to a dynamic elimination circuit for DC offset output of a step-down DC-DC converter based on ripple control with constant turn-on time. Background technique

[0002] With the wide application of portable electronic devices, the market demand for power management integrated circuits continues to rise, and step-down (Buck) DC-DC converters are widely used in communications, computers, industrial automation and other fields. Traditional step-down DC-DC converters have three control modes, namely current mode, voltage mode and hysteresis control. The Ripple-based Constant On-time Control scheme (Ripple-based Constant On-time Control) is a type of hysteretic mode control, and is widely used due to its simple control, no need for external compensation, excellent load regulation and efficiency, etc. .

[0003] For traditional step-down converters, there is a cert...

Claims

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