LLC Resonant Power Supply IC for Fast Load-Change Voltage Control
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Solution Overview
Problem
Existing integrated circuits for LLC current resonance converters struggle to maintain output voltage stability when load conditions change suddenly, leading to temporary drops in output voltage due to delayed switching mode adjustments.
Innovation Solution
The integrated circuit includes a control circuit that adjusts the switching of transistors based on feedback voltage derivatives, increasing and decreasing current to the capacitor in response to sudden load changes, ensuring rapid mode transitions and maintaining output voltage stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the integrated circuit uses a conventional load detection circuit that generates voltage based on load current, then the circuit structure is simple, but the output voltage drops when load state changes suddenly because the load detection voltage cannot follow the sudden change
Solution Approach 1:
The patent applies dynamics by making the current supply to the second capacitor changeable based on operating conditions. The control circuit dynamically adjusts the current supplied to the second capacitor depending on whether the power supply circuit is in light-load or normal-load state, enabling the load detection voltage to rapidly follow sudden load changes while maintaining circuit simplicity.
Solution Approach 2:
The patent changes the electrical parameter (current) supplied to the second capacitor based on load conditions. By increasing or decreasing the current to the second capacitor according to the load state, the load detection voltage can quickly reach the required level when load changes occur, preventing output voltage drops without complicating the overall circuit structure.
2Reliability
If the integrated circuit increases the response speed of load detection voltage to sudden load changes, then output voltage stability is maintained, but the circuit complexity increases due to additional control mechanisms
Solution Approach 1:
The patent uses feedback by having the control circuit monitor the operating state (light-load or normal-load) and adjust the current to the second capacitor accordingly. This feedback mechanism enables rapid response to load changes while keeping the control structure relatively simple, as it only requires detecting the load state and adjusting one current parameter.
Solution Approach 2:
The patent applies preliminary action by pre-adjusting the current to the second capacitor based on the detected load state before output voltage drops occur. When a sudden load change is detected, the control circuit has already positioned the current at an appropriate level, allowing the load detection voltage to immediately follow the load change without requiring complex real-time control mechanisms.
3Reliability
If the integrated circuit maintains continuous switching mode during light load state, then output voltage remains stable, but energy consumption increases due to unnecessary switching operations
Solution Approach 1:
The patent applies dynamics by making the switching mode adaptive to load conditions. The control circuit dynamically switches between continuous switching mode and intermittent switching mode based on whether the power supply circuit is in normal-load or light-load state, respectively. This enables energy savings during light-load operation while maintaining output voltage stability when needed.
Solution Approach 2:
The patent changes the switching operation parameter based on load state. By adjusting the switching duty cycle or frequency according to the detected load condition, the system reduces energy consumption during light-load periods while ensuring output voltage remains stable during normal-load conditions, achieving optimal trade-off between energy efficiency and voltage stability.
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 enables rapid adjustment of switching modes to prevent output voltage drops during sudden load changes, effectively maintaining target voltage levels.
Implementation Method 1
a resonant circuit including the primary coil and a first capacitor
Implementation Method 2
a transformer including a primary coil and a secondary coil
Data Source
AI summary
An integrated circuit for a power supply circuit that generates an output voltage, and that includes: a transformer including primary and secondary coils, first and second transistors controlling a current of the primary coil, and a resonant circuit including the primary coil and a first capacitor. The integrated circuit controls the first and second transistors. The integrated circuit includes: a voltage generator circuit supplying a first current to a second capacitor, and to generate a first voltage at the second capacitor; a driving signal output circuit outputting a driving signal for driving the first and second transistors, based on the first voltage and a feedback voltage corresponding to the output voltage; and a control circuit controlling the voltage generator circuit such that, when the output voltage drops and a derivative of the feedback voltage at a time point is greater than a predetermined value, the first current increases and then decreases.