DC-DC Converter Current Limiting with Stored Voltage Thresholds
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Digitally controlled DC to DC converters face challenges in implementing a simple and cost-effective steady state current limitation mechanism to protect the converter and load from over-currents.
Innovation Solution
A method and circuit that store values representative of output voltage levels when current thresholds are exceeded or fallen below, modifying the control signal to bring the output voltage to intermediate levels between these values, and maintaining these signals for a fixed time delay to stabilize current limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a steady state current limitation mechanism is implemented in a digitally controlled DC to DC converter, then the converter and load are protected from over-currents, but the device complexity and cost increase
Solution Approach 1:
The patent uses a digital copy of the output voltage signal (stored in a register) to represent the voltage level at which current thresholds are exceeded. This digital copy allows the controller to compare and adjust the control signal without requiring additional analog sensing circuitry, thereby providing over-current protection while maintaining low complexity and cost
Solution Approach 2:
The patent replaces traditional analog current limitation circuits with a digital control mechanism. The controller uses digital signal processing to store voltage levels, compare currents against thresholds, and adjust the control signal accordingly. This substitution of analog mechanisms with digital processing reduces device complexity and eliminates the need for analog-to-digital conversion
2Reliability
If traditional current limitation methods are used, then over-current protection is provided, but undesirable oscillations occur in the output voltage
Solution Approach 1:
The patent implements a feedback mechanism where the controller continuously monitors the output current, compares it against predefined thresholds, and adjusts the control signal based on the stored digital voltage level. This feedback loop provides stable over-current protection by making incremental adjustments rather than abrupt changes, thereby preventing output voltage oscillations while maintaining reliable protection
Solution Approach 2:
The patent applies partial action by adjusting the control signal to an intermediate level rather than immediately reducing it to minimum when over-current is detected. The controller modifies the control signal based on the stored voltage level to bring the output voltage to an intermediate level, providing gradual current limitation that maintains output voltage stability while still protecting against over-current conditions
Data Source
AI summary
In an embodiment a DC to DC conversion circuit includes a DC to DC converter connected to an input path and an output path and a current limiting circuit including a circuit configured to detect when an input or output current of the DC to DC converter exceeds or falls below a current threshold and a controller configured to store a first voltage level of an output voltage of the DC to DC converter in response to the input or output current exceeding the current threshold, to store a second voltage level of the output voltage in response to the input or output current falling below the current threshold and to set a control signal based on the first and second voltage levels.