Voltage Regulator Mode Transition Hysteresis Control
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Solution Overview
Problem
Conventional DC-DC voltage regulators experience inefficiencies due to toggling between dual and single phase modes, leading to overshoot issues and misinterpretation of load conditions, which worsens power efficiency.
Innovation Solution
A voltage regulator with a controller that uses multiple thresholds and a time delay to determine mode transitions, preventing unnecessary switching between dual and single phase modes by assessing output currents against different thresholds at different times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the DC-DC voltage regulator switches from dual phase mode to single phase mode when load current decreases, then power efficiency is improved, but output current overshoot occurs and the regulator may incorrectly switch back to dual phase mode
Solution Approach 1:
The patent introduces two different thresholds (first threshold and second threshold) for comparing output current to determine mode transitions. The first threshold is used when switching from dual phase to single phase mode, while the second threshold is used when switching from single phase to dual phase mode. This parameter change creates a hysteresis effect that prevents toggling between modes by ensuring the second threshold is lower than the first threshold, thus resolving the instability issue while maintaining power efficiency improvements.
2Reliability
If the DC-DC voltage regulator immediately switches back to dual phase mode when load current decreases, then output current overshoot is prevented, but power efficiency deteriorates due to unnecessary mode switching
Solution Approach 1:
The patent implements a time delay mechanism that prevents immediate switching back to dual phase mode. After switching from dual phase to single phase mode, the regulator waits for a predetermined time period before allowing a switch back to dual phase mode. This preliminary action filters out transient current variations and prevents unnecessary mode toggling, thereby maintaining power efficiency while still responding to genuine load changes.
3Device complexity
If the DC-DC voltage regulator uses a single threshold for mode transitions, then the control logic is simple, but toggling between dual phase and single phase modes occurs continuously
Solution Approach 1:
The patent changes the threshold parameter from a single value to two distinct values (first threshold and second threshold) depending on the direction of mode transition. This creates a hysteresis window that stabilizes mode transitions by requiring the output current to cross different threshold levels for switching in opposite directions, thereby preventing continuous toggling while adding minimal complexity to the control logic.
Data Source
AI summary
A voltage regulator includes a plurality of output stages and a controller. The plurality of output stages are arranged for selectively enabling to generate output voltages and output currents or not according to a plurality of control signals, respectively. The controller is arranged for sensing the output currents of the output stages, and generating the control signals according to the sensed output currents. When the controller generates the control signals to reduce a quantity of the enabled output stages, the controller determines whether a summation of the sensed output currents is greater than a first threshold or not to determine whether to enable more output stages, then a period of time later, the controller selectively determines whether the summation of the sensed output currents is greater than a second threshold or not to determine whether to enable more output stages, wherein the second threshold is lower than the first threshold.