Multiphase Buck Converter Quick Response for Overvoltage Control
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Solution Overview
Problem
Conventional quick response mechanisms in buck converters face issues with inaccurate timing of switch operation, leading to unexpected ringback and continuous output voltage rise, resulting in overvoltage during load transient conditions.
Innovation Solution
The implementation of a buck converter with a quick response circuit, including a voltage droop sensor, load frequency sensor, quick response signal generator, maximum quick response signal generator, and AND gate, along with a compensator and interleaving logic circuit, to generate precise PWM signals and control the output voltage, preventing overvoltage by adjusting the width of the quick response signal based on load frequency and input voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a conventional quick response mechanism is used to immediately turn on all phases of high side switches during load application transient, then the output voltage droop can be controlled within the load line specification, but inaccurate timing of turning on and off the switches may cause unexpected ringback or continuous output voltage rise resulting in overvoltage
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing optimal switch timing parameters (on-time and off-time) in lookup tables before load transients occur. When a transient is detected, the pre-computed timing values are immediately applied, ensuring both fast response and accurate timing without real-time calculation delays or errors.
Solution Approach 2:
The patent implements feedback by continuously monitoring the output voltage and inductor current, comparing them against reference values, and using this information to dynamically adjust the switch timing. The feedback loop ensures that switches are turned on and off at precisely the right moments, preventing both voltage droop and overvoltage conditions.
2Power
If the quick response signal width is extended to ensure sufficient current supply during load transient, then the load current demand can be met, but the total inductor current may not return to its original level causing energy buildup and overvoltage
Solution Approach 1:
The patent applies dynamics by making the quick response signal width adaptive rather than fixed. The signal duration is dynamically adjusted based on real-time monitoring of the total inductor current and load conditions. The system extends the signal width only as long as needed to meet current demand, then automatically terminates it when the inductor current returns to its steady-state level, preventing energy buildup.
Solution Approach 2:
The patent uses feedback to monitor the total inductor current during and after the quick response period. When the feedback detects that the inductor current has returned to its original level, the system automatically terminates the quick response signal, ensuring that energy is supplied only when needed and preventing energy buildup that would cause overvoltage.
3Power
If multiphase control is used to satisfy high power density and high current slew rate requirements, then the power delivery capability is improved, but the conventional multiphase control is still insufficient to handle the ultra-high load transient of modern voltage regulator specifications
Solution Approach 1:
The patent applies preliminary action by pre-calculating the optimal on-time and off-time parameters for each phase based on expected load transient conditions. These pre-computed values are stored in lookup tables, allowing the multiphase controller to immediately switch all phases on with precise timing during ultra-high load transients, exceeding the capability of conventional sequential multiphase control.
Solution Approach 2:
The patent implements dynamics by enabling all multiphase switches to operate simultaneously with dynamically adjusted timing parameters during ultra-high load transients. This dynamic coordination of multiple phases, controlled by the microcontroller with precise timing, allows the system to deliver the required current slew rate and power density that conventional multiphase control cannot achieve.
Data Source
AI summary
A buck converter includes a quick response circuit, a compensator coupled to an output node, an interleaving logic circuit coupled to the compensator, a plurality of on-time generators, a plurality of OR gates coupled to the corresponding on-time generator, a plurality of power stages coupled to the corresponding OR gates, a plurality of inductors and an output capacitor. Each on-time generator is coupled to the interleaving logic circuit, an input node and the output node. The quick response circuit includes a voltage droop sensor coupled to the output node, a load frequency sensor coupled to the output node, a quick response signal generator coupled to the voltage droop sensor, a maximum quick response signal generator coupled to the voltage droop sensor and the load frequency sensor, an AND gate coupled to the quick response signal generator, the maximum quick response signal generator and the plurality of OR gates.