Resonance Converter Burst Controller Pulse Width Adjustment
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Solution Overview
Problem
Resonance converters face efficiency issues when transitioning from continuous control to burst control at light loads, as the burst cycle length can extend into audible frequencies, causing inefficiencies and potential noise due to inadequate control over the switching stop period and pulse widths.
Innovation Solution
A burst controller for resonance converters that includes a load detection circuit and an on-pulse generation circuit, which adjusts the on-width of the main pulse based on the detected load, ensuring optimal efficiency by maintaining the burst cycle within non-audible frequency ranges and reducing energy transmission during light loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If burst control is used at light load to improve efficiency, then energy consumption is reduced, but the burst cycle length extends into audible frequencies causing noise and inefficiency
Solution Approach 1:
The patent dynamically adjusts the main pulse width based on detected load conditions. At light load, the main pulse width is reduced to shorten the burst cycle duration, preventing it from extending into audible frequencies. This dynamic adjustment maintains efficiency benefits while eliminating noise problems.
Solution Approach 2:
The patent changes the pulse width parameter in response to load detection. When light load is detected, the control circuit reduces the main pulse width from its normal value, thereby controlling the burst cycle length to remain below audible frequency thresholds while still achieving energy savings.
2Power
If the main pulse width is increased to improve energy transmission, then power delivery is enhanced, but efficiency decreases at light loads
Solution Approach 1:
The patent adjusts the main pulse width parameter based on load detection. At light load conditions, the main pulse width is reduced to minimize energy transmission and improve efficiency. At heavy load conditions, the main pulse width is increased to enhance power delivery capability.
Solution Approach 2:
The control circuit dynamically modifies the main pulse width in real-time based on the detected load state, enabling the system to optimize the balance between power delivery and energy efficiency under different operating conditions.
3Device complexity
If fixed pulse widths are used in burst control, then control simplicity is maintained, but adaptability to varying load conditions is reduced
Solution Approach 1:
The patent incorporates a feedback mechanism where the control circuit detects the actual load condition and adjusts the main pulse width accordingly. This feedback loop enables the system to adapt to varying load conditions while maintaining relatively simple control circuitry based on load detection thresholds.
Solution Approach 2:
The control circuit automatically adjusts the main pulse width based on detected load conditions without requiring external intervention. The system self-regulates its operation by comparing detected load levels with threshold values and autonomously modifying pulse parameters.
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
The solution effectively optimizes the burst cycle duration and energy transmission, preventing inefficiencies and noise by dynamically adjusting pulse widths in response to load changes, thereby enhancing the overall efficiency and performance of the resonance converter.
Implementation Method 1
a resonance circuit including a resonance inductor Lr, an excitation inductor Lm of a transformer T, and a resonance capacitor Cr connected in series
Implementation Method 2
an excitation inductor Lm of a transformer T... The other end of the excitation inductor Lm is connected to one end of a resonance capacitor Cr
Data Source
AI summary
A switching period in a burst cycle includes three pulses, that is to say, a start pulse that turns on a low-side switching element, a main pulse that turns on a high-side switching element, and an end pulse that turns on the low-side switching element. A burst stop period corresponding to the magnitude of a load is set during a switching stop period. When the burst cycle approaches a cycle corresponding to a frequency close to the upper limit of the audible frequencies, a second off-threshold voltage of the main pulse is made equal to a first off-threshold voltage of the start pulse to narrow the on-width of the main pulse. By doing so, energy transmitted to the secondary side of a transformer is reduced and the burst cycle is shortened.