Voltage Boosting Circuit with Negative Feedback Control
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Solution Overview
Problem
The existing DC-DC converter in digital still cameras experiences increased fluctuations in output voltage when the input voltage approaches the target output voltage, due to its reliance on detecting only the input voltage for switching between voltage-boosting and voltage-lowering operations, leading to delayed voltage-boosting and subsequent abrupt voltage rises, resulting in larger overshoots.
Innovation Solution
A voltage boosting/lowering circuit that incorporates an output voltage generation circuit with switch elements, a clock generation circuit, and a switch control unit for negative feedback control, allowing precise switching based on output voltage feedback to maintain stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If switching between voltage-boosting and voltage-lowering operations is controlled by detecting only the input voltage, then the circuit structure remains simple, but the output voltage fluctuations increase when input voltage approaches target output voltage
Solution Approach 1:
The patent introduces output voltage feedback control where the output voltage is continuously detected and fed back to the control unit. The control unit compares the detected output voltage with the target output voltage and adjusts the switching timing of the voltage boosting/lowering operation accordingly. This feedback mechanism enables precise control of the output voltage, preventing fluctuations and overshoots when the input voltage approaches the target output voltage, while maintaining a relatively simple circuit structure.
2Device complexity
If switching timing is determined solely by input voltage detection, then the control logic remains simple, but voltage-boosting operation is delayed causing abrupt voltage rises and larger overshoots
Solution Approach 1:
The control unit uses output voltage feedback to determine the optimal switching timing between voltage-boosting and voltage-lowering operations. By continuously monitoring the output voltage and comparing it with the target value, the control unit can proactively adjust the switching timing before significant deviations occur. This prevents delayed voltage-boosting responses and reduces abrupt voltage rises, thereby improving output voltage accuracy without significantly complicating the control logic.
Solution Approach 2:
The feedback control mechanism enables preliminary action by detecting trends in output voltage deviation and adjusting switching timing in advance. When the output voltage approaches the target value, the control unit anticipates potential overshoots and adjusts the switching timing beforehand, preventing abrupt voltage rises before they occur. This proactive control improves voltage accuracy while maintaining simple control logic.
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
This approach reduces fluctuations in the output voltage by enabling continuous negative feedback control, ensuring the output voltage remains close to the target voltage, minimizing overshoots and improving stability.
Implementation Method 1
an output voltage generation circuit including a first switch element connected between an input terminal and one end of a choke coil and a second switch element connected between another end of the choke coil and a ground terminal, the output voltage generation circuit being configured to boost or lower an input voltage input to the input terminal and thereby to generate an output voltage by switching the first and second switch elements between an On-state and an Off-state
Data Source
AI summary
A voltage boosting/lowering circuit in accordance with present invention includes an output voltage generation circuit including a first switch element connected between an input terminal and one end of a choke coil and a second switch element connected between the other end of the choke coil and a ground terminal, the output voltage generation circuit being configured to boost or lower an input voltage input to the input terminal and thereby to generate an output voltage by switching the first and second switch elements between an On-state and an Off-state. Further, voltage boosting/lowering circuit includes a clock generation circuit that generates voltage-boosting and voltage-lowering clocks having different timings, and a switch control unit that performs switching control of the first and second switch elements based on the voltage-boosting and voltage-lowering clocks so that negative feedback control is performed so as to bring the output voltage to a target output voltage.