PFC Standby Switching Control for Burst-Mode Noise Reduction
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Solution Overview
Problem
Power factor correction (PFC) circuits operating in burst mode generate noise due to magnetic interference from peak currents, which existing solutions attempt to mitigate through shielding cores, increasing manufacturing costs and reducing workability.
Innovation Solution
An electronic apparatus with a PFC circuit and control circuit that operates in a standby mode by adjusting the output voltage and identifying an on-off frequency for the switch based on a reference current level to limit peak currents, preventing noise generation without the need for shielding cores.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If shielding cores are used to mitigate noise from peak currents in PFC circuits, then noise reduction is achieved, but manufacturing cost increases and workability decreases
Solution Approach 1:
The patent extracts and removes the shielding core from the PFC circuit design entirely. Instead of adding protective elements, the solution eliminates the source of the problem by operating the PFC circuit in burst mode with controlled peak currents, thereby achieving noise mitigation without any shielding structures.
Solution Approach 2:
The patent changes the operational parameters of the PFC circuit by implementing burst mode operation. This involves modifying the switching frequency and duty cycle parameters to limit peak currents to below 30A, thereby reducing magnetic interference and noise generation without requiring additional shielding components.
2Power
If PFC circuit operates in burst mode with peak currents, then power conversion is achieved, but noise is generated due to magnetic interference
Solution Approach 1:
The patent implements periodic burst mode operation where the PFC circuit switches between active and standby states. The circuit operates in short bursts with controlled duration and frequency, converting power efficiently while limiting continuous peak current exposure that causes magnetic interference and noise.
Solution Approach 2:
The patent maintains continuous power conversion functionality through burst mode operation. By keeping the PFC circuit in a ready state with quick start-up capability and maintaining output voltage regulation during bursts, the useful power conversion action continues without interruption despite the periodic switching nature.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Effectively reduces noise generation in PFC circuits during burst mode operations by controlling peak currents, thereby enhancing operational efficiency and reducing manufacturing costs.
Implementation Method 1
a power factor correction (PFC) circuit including an inductor and a switch serially connected to the inductor
Data Source
AI summary
An electronic apparatus includes a power factor correction (PFC) circuit including an inductor and a switch serially connected to the inductor, and a control circuit. The control circuit, based on an amount of current flowing in the PFC circuit being less than or equal to a threshold current, operates the PFC circuit in a standby mode, and based on an output voltage of the PFC circuit being less than a threshold output voltage corresponding to the standby mode, adjusts the output voltage to correspond to a reference voltage by applying a signal for on-off control of the switch in the PFC circuit to the switch. The control circuit identifies an on-off frequency of the switch based on a reference current level for limiting a peak current of the inductor included in the PFC circuit in the standby mode, and applies the signal to the switch based on the on-off frequency.