Boost Converter Down-Mode Control for Low-Loss Voltage Regulation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In boost converters, when the input voltage exceeds the output voltage, especially during start-up or load changes, the high side power switch operates in a variable resistance region, leading to increased power loss and instability due to output voltage undershoot.
Innovation Solution
A control circuit is introduced that includes a logical circuit and a process circuit to manage the high side and low side power switches. The control circuit generates specific control signals to control the high side power switch to operate fully ON for a set time when the input voltage is higher than the output voltage, and then transition to a linear mode if the set time expires without a reset signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the high side power switch operates in the variable resistance region during down mode, then the output voltage can be regulated when input voltage exceeds output voltage, but power loss increases and efficiency decreases
Solution Approach 1:
The patent applies dynamics by transitioning the high side power switch from static linear region operation to dynamic switching between fully ON and fully OFF states. The control circuit dynamically adjusts the switch state based on whether the converter is in boost mode or down mode, eliminating the static variable resistance operation that caused power loss while maintaining the ability to regulate output voltage during down mode through controlled switching sequences.
2Adaptability or versatility
If the high side power switch operates in the variable resistance region during down mode, then output voltage regulation is achieved, but output voltage stability deteriorates due to undershoot
Solution Approach 1:
The control circuit dynamically manages the high side power switch state based on operating mode. During down mode, it fully turns on the switch for a controlled duration to deliver input voltage to output, then fully turns it off, avoiding the unstable linear region operation. This dynamic switching approach maintains output voltage regulation capability while eliminating the undershoot and stability issues associated with variable resistance operation.
Solution Approach 2:
The control circuit uses feedback from voltage comparison (input voltage vs. output voltage) to determine operating mode and adjust high side power switch control accordingly. When input voltage exceeds output voltage, the circuit detects this condition and switches to down mode control strategy, ensuring stable output voltage regulation without undershoot by avoiding linear region operation.
3Loss of energy
If the high side power switch is fully turned on during down mode, then power loss is reduced, but the ability to regulate output voltage when input exceeds output is compromised
Solution Approach 1:
The patent applies periodic action by implementing controlled switching sequences where the high side power switch is fully turned on for specific time intervals during down mode, then fully turned off. This periodic switching, governed by the control circuit based on mode detection, maintains output voltage regulation capability through timed voltage delivery while keeping the switch in low-loss fully ON or fully OFF states rather than variable resistance region.
Data Source
AI summary
A boost converter with down mode is discussed. The boost converter detects whether the input voltage is higher than the output voltage. If the input voltage is lower than the output voltage, a high side power switch and a low side power switch are controlled to operate between fully ON and fully OFF states. If the input voltage is larger than the output voltage, and a difference between the input voltage and the output voltage is large, the high side power switch to operate between a fully OFF state and a mix state: a) first operate at a fully ON state for a set time length; and b) then operate at a linear mode after the set time length is over.