DC-DC Converter Control Circuit for Negative Feedback
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Solution Overview
Problem
Inverting DC-DC converters require complex configurations to convert negative feedback voltages into positive voltages for comparison with reference potentials, limiting the usability of controllers across different DC-DC converter types.
Innovation Solution
A DC-DC converter design incorporating a power conversion portion with resistors and a control circuit that uses a reference current to simplify the control circuit configuration, allowing for the conversion of negative feedback voltages into positive voltages, enabling a simple control circuit that can be applied across various DC-DC converter types, including inverting and Cuk converters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a negative-to-positive voltage conversion circuit is added to the controller to convert the negative feedback voltage into a positive voltage, then the feedback voltage can be compared with the reference potential, but the configuration of the controller becomes complex
Solution Approach 1:
The patent introduces an intermediary circuit between the feedback voltage input and the comparison operation. This intermediary circuit converts the negative feedback voltage into a positive voltage that can be compared with the reference potential, while keeping the conversion function separate from the main controller logic, thus resolving the contradiction between achieving voltage comparison and maintaining controller simplicity
Solution Approach 2:
The patent segments the controller functionality by separating the voltage conversion function from the main control logic. The negative-to-positive voltage conversion is implemented as a distinct circuit module, allowing the main controller to remain simple while still achieving the necessary feedback voltage comparison capability
2Reliability
If a complex controller configuration is used to handle negative feedback voltages, then the feedback can be properly processed, but the same controller cannot be used for step-up, step-down, or other DC-DC converter types
Solution Approach 1:
The patent designs the voltage conversion circuit with universal applicability, using a standardized approach that can handle negative feedback voltages from inverting DC-DC converters while maintaining compatibility with other DC-DC converter architectures. This allows a single controller design to serve multiple converter types, resolving the contradiction between specialized feedback processing and general versatility
Data Source
AI summary
A DC-DC converter includes a power conversion portion including a switching element; a first resistor having one terminal electrically connected to the power conversion portion; a second resistor having one terminal electrically connected to the other terminal of the first resistor; a third resistor having one terminal electrically connected to the other terminal of the first resistor; a constant current supply electrically connected to the other terminal of the third resistor; and a control circuit electrically connected to the other terminal of the third resistor and configured to control the switching element. Resistance R1 of the first resistor, resistance R2 of the second resistor, resistance R3 of the third resistor, a reference current Iref output from the constant current supply, and an output voltage Vout output from the power conversion portion satisfy a following formula:{(1+R3R2)·R1+R3}·Iref>-Vout.