Burst-Mode Switching Regulator Control for Low Audio Noise
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Solution Overview
Problem
Switching voltage regulators experience high inductor current peaks and audio noise during low load conditions, leading to malfunctioning and user disturbance.
Innovation Solution
A control device for a switching voltage regulator that operates in burst mode, using a burst-mode controller to monitor output voltage thresholds and generate switching control signals based on error and burst signals, reducing inductor current peaks and audio noise through controlled switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the regulator operates in continuous switching mode to maintain proper output voltage regulation, then the output voltage remains stable within reference interval, but high inductor current peaks occur during light-load conditions causing audio noise and potential malfunctioning
Solution Approach 1:
The patent implements burst mode operation where the regulator switches between active switching periods and idle periods. During light-load conditions, the regulator performs brief bursts of switching activity to maintain output voltage, then enters idle mode. This periodic action eliminates continuous high-frequency switching that causes audio noise while still providing adequate voltage regulation through intermittent control cycles.
Solution Approach 2:
The control device dynamically adjusts its operating mode based on load conditions. It transitions from continuous conduction mode (CCM) at heavy loads to burst mode at light loads. This dynamic adaptation allows the regulator to optimize performance across different operating conditions, reducing audio noise during light-load operation while maintaining stable regulation during heavy loads.
2Use of energy by moving object
If the second high-side switch is kept in open state to reduce switching events and energy consumption, then energy efficiency improves, but output voltage tends to grow beyond desired regulation value particularly at light load
Solution Approach 1:
In burst mode, the second high-side switch remains open during idle periods to minimize switching events and energy consumption. The control device periodically activates the switch during brief switching bursts when regulation is needed, then returns to the open state. This periodic activation maintains voltage regulation while keeping average energy consumption low.
Solution Approach 2:
The control device uses feedback from the output voltage to determine when to activate the second high-side switch. When output voltage approaches the upper threshold during idle mode, the feedback signal triggers a switching burst that closes the switch temporarily. This feedback-controlled activation ensures voltage regulation is maintained only when necessary, optimizing the trade-off between energy consumption and regulation stability.
3Loss of energy
If burst mode is implemented to reduce switching events and energy consumption, then energy efficiency and audio noise are improved, but complex control logic is needed to manage switching between modes
Solution Approach 1:
The control device employs feedback signals from voltage threshold comparisons to automatically determine when to transition between CCM and burst mode. The feedback mechanism monitors output voltage and triggers mode transitions based on predefined thresholds, eliminating the need for complex external control logic while achieving efficient burst mode operation.
Solution Approach 2:
The regulator performs self-diagnosis and self-adjustment by monitoring its own output voltage and automatically switching between operating modes. The control device uses internal voltage threshold comparisons to trigger mode transitions without requiring external intervention or complex control algorithms, allowing the system to optimize its own performance based on real-time operating conditions.
Data Source
AI summary
A control device for a switching voltage regulator having a switching circuit receives a set of measurement signals including a first measurement signal indicative of an output voltage of the switching voltage regulator. A burst-mode controller is configured to monitor the output voltage with respect to a first threshold and a second threshold higher than the first threshold, and to provide, in response, a burst signal. A driving-signal generation stage is configured to provide at least one switching control signal for the switching circuit based on the burst signal and the set of measurement signals. The driving-signal generation stage has a feedback module configured to provide a control signal based on the burst signal and an error signal indicative of a difference between the first measurement signal and a reference signal.