Switching Control Circuit With Delayed Ripple Cancellation
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Solution Overview
Problem
Existing power supply circuits that convert AC voltage to DC voltage using switching control circuits often suffer from ripple components in the output voltage, which are difficult to eliminate without increasing the size of the circuit through larger capacitors.
Innovation Solution
A switching control circuit that processes and delays a ripple component in the output voltage by a predetermined period of time, allowing it to be subtracted or added back to itself, thereby removing the ripple from the output voltage while maintaining a compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional switching control circuit is used to generate DC voltage from AC voltage, then the power supply circuit can operate with basic functionality, but a ripple component appears in the output voltage that is difficult to eliminate
Solution Approach 1:
The patent extracts the ripple component from the output voltage by using a ripple detection circuit that separates the ripple signal from the main output voltage. This extracted ripple signal is then processed through a delay circuit and subtracted from the original output voltage, effectively removing the harmful ripple component while preserving the stable DC voltage.
Solution Approach 2:
The patent introduces an intermediary processing path that includes a delay circuit and a subtraction circuit. The ripple component is detected, delayed by a predetermined period matching the AC voltage cycle, and then subtracted from the output voltage through an intermediary calculation process, serving as a mediator to eliminate the ripple without affecting the main power conversion function.
2Reliability
If large capacitors are used to reduce the ripple component, then the output voltage stability improves, but the circuit size increases
Solution Approach 1:
The patent replaces the traditional mechanical approach of using large physical capacitors to filter ripple with an electronic signal processing system. Instead of physically blocking or absorbing the ripple through larger energy storage components, the system uses electronic detection, timing, and subtraction operations to remove the ripple component, significantly reducing the required circuit volume while achieving the same stability improvement.
Solution Approach 2:
The patent changes the approach from modifying physical parameters (capacitor size) to modifying signal parameters (timing and amplitude of control signals). By adjusting the delay period to match the AC voltage cycle and controlling the subtraction amount, the system achieves ripple reduction through parameter optimization rather than physical component scaling.
3Reliability
If the output voltage is processed with delay and subtraction operations, then the ripple component is removed, but the processing circuit complexity increases
Solution Approach 1:
The patent applies preliminary action by detecting the ripple component in advance and preparing the delayed version of the ripple signal before it is needed for subtraction. The delay circuit pre-processes the ripple signal by the predetermined period corresponding to the AC voltage cycle, so that when the subtraction occurs, both signals are properly synchronized, simplifying the overall control logic.
Solution Approach 2:
The patent implements feedback by continuously monitoring the output voltage for ripple components and using this information to generate the appropriate delayed subtraction signal. The ripple detection circuit provides feedback about the ripple amplitude and phase, which is then used to adjust the subtraction operation, creating a closed-loop system that automatically maintains optimal ripple cancellation.
Data Source
AI summary
A switching control circuit for controlling a power supply circuit that includes an inductor receiving a rectified voltage corresponding to an AC voltage, and a transistor controlling an inductor current flowing through the inductor. The switching control circuit controls switching of the transistor, and includes an output circuit, a processing circuit and a drive signal output circuit. The output circuit sequentially receives a first voltage, which fluctuates at a frequency twice a frequency of the AC voltage, and outputs, as a second voltage, the received first voltage after a delay of a predetermined period of time. The processing circuit processes the first voltage based on a value corresponding to the second voltage, to remove a ripple component generated in an output voltage and contained in the first voltage. The drive signal output circuit outputs a drive signal for driving the transistor, in response to a processing result of the processing circuit.