A controller and control method for suppressing magnetic bias of an asymmetrical half-bridge converter

By introducing a VCr asymmetric detection mechanism and a dual-path compensation minimum value arbitration architecture into the AHB converter, the problem of bias magnetic suppression blind zone in the AHB converter under a wide input voltage range is solved, and accurate sensing and compensation of the resonant capacitor voltage state are achieved, ensuring system stability and efficiency.

CN122159633APending Publication Date: 2026-06-05WUXI SI POWER MICRO ELECTRONICS
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
WUXI SI POWER MICRO ELECTRONICS
Filing Date
2026-05-09
Publication Date
2026-06-05

AI Technical Summary

Technical Problem

In the existing AHB converter control architecture, neither the current sampling signal VCS nor the secondary feedback signal VFB contains information about the voltage state of the resonant capacitor Cr. This results in a magnetic bias suppression blind zone under wide input voltage range conditions, making it impossible to actively sense and correct the cycle-by-cycle asymmetric accumulation of the resonant capacitor voltage. Consequently, the magnetic flux of the transformer core cannot be fully reset, which may lead to transformer burnout or overcurrent damage to the switching transistor.

Method used

By introducing a VCr asymmetric detection mechanism and a dual-path compensation minimum value arbitration architecture, the system actively senses and suppresses the cycle-by-cycle asymmetric accumulation of the resonant capacitor voltage through a CS sample/hold module, a CS linear compensator, a VCr asymmetric detection module, a Ton nonlinear compensator, and a minimum arbitrator. This is integrated into the control chip to achieve accurate sensing and compensation of the Cr voltage state.

Benefits of technology

Without adding extra high-voltage sampling pins, it accurately senses the voltage state of the resonant capacitor, eliminates magnetism issues, avoids output ripple exceeding specifications, improves system stability and efficiency, and prevents damage to transformers and switching devices.

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Abstract

The application relates to a controller and a control method for inhibiting magnetic bias of an asymmetric half-bridge converter. The application comprises a CS sampling / holding module for receiving a primary-side current sampling signal and outputting a holding value; a CS linear compensator for generating a first compensation quantity; a VCr asymmetric detection module for calculating the difference between two sampling values; a Ton nonlinear compensator for generating a second compensation quantity; a minimum arbitrator for selecting a smaller value from the first compensation quantity and the second compensation quantity and outputting a control correction quantity; a subtractor for generating a dynamic reference voltage signal for turning off a high-side switch according to the control correction quantity; and a PWM logic control module for comparing the primary-side current sampling signal and the dynamic reference voltage signal during the conduction of the high-side switch, and outputting a turn-off instruction for driving the high-side switch to turn off by a high-side drive module when the primary-side current sampling signal reaches the dynamic reference voltage signal. The application can eliminate the magnetic bias problem under the wide input range working condition.
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