Multi-Phase Power Converter Green Mode for Light-Load Efficiency
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Solution Overview
Problem
Switched mode power converters suffer from efficiency losses at lighter loads due to high power consumption from digital controllers with higher sampling rates, leading to instability and reduced efficiency.
Innovation Solution
A multi-phase power converter with a digital ramp pulse modulation controller and a digital constant on-time/green mode controller that adjusts operation modes based on load conditions, disabling high-power components under light loads to maintain efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If digital controllers operate at higher sampling rates to reduce loop latency and improve stability, then dynamic performance and stability are improved, but power consumption increases leading to reduced efficiency at lighter loads
Solution Approach 1:
The controller dynamically adjusts the sampling rate based on load conditions. At heavy loads, a higher sampling rate is used to maintain stability and fast transient response. At light loads, the sampling rate is reduced to minimize power consumption, thus resolving the contradiction between stability and energy efficiency across different operating conditions
Solution Approach 2:
The system changes the sampling rate parameter according to load levels. By having multiple sampling rate modes and switching between them based on load detection, the system optimizes the trade-off between loop latency (affecting stability) and power consumption, particularly improving efficiency at light loads while maintaining adequate performance at heavy loads
2Adaptability or versatility
If digital controllers are used for programmability and noise robustness, then control flexibility and robustness are improved, but discrete nature causes large loop latency compromising stability and dynamic performance
Solution Approach 1:
The system dynamically adjusts the sampling rate based on load conditions. At heavy loads, a higher sampling rate is used to maintain stability and fast transient response. At light loads, the sampling rate is reduced to minimize power consumption, thus resolving the contradiction between stability and energy efficiency across different operating conditions
Solution Approach 2:
The system changes the sampling rate parameter according to load levels. By having multiple sampling rate modes and switching between them based on load detection, the system optimizes the trade-off between loop latency (affecting stability) and power consumption, particularly improving efficiency at light loads while maintaining adequate performance at heavy loads
3Power
If multi-phase power converter operates all phases under light load conditions, then power delivery capability is maintained, but power loss increases reducing efficiency
Solution Approach 1:
Under light load conditions, the controller disables certain phases by preventing their switch nodes from switching, effectively extracting or removing the contribution of those phases from the power conversion process. This reduces the active switching components and associated losses, improving efficiency when full power delivery capability is not required
Solution Approach 2:
The system dynamically adjusts the number of active phases based on load conditions. At heavy loads, all phases are active to provide maximum power delivery. At light loads, fewer phases are activated, dynamically adapting the power converter's operation to match the actual power demand and minimize losses
Data Source
AI summary
A multi-phase power converter includes a digital ramp pulse modulation controller, a digital constant on-time controller, and a driver stage. The digital ramp pulse modulation controller provides a trigger ramp signal in response to an error signal when the multi-phase power converter is not in a green mode, wherein at least a portion of the digital ramp pulse modulation controller is inactive in the green mode. The digital constant on-time controller provides on-time thresholds and off-time thresholds when the multi-phase power converter is in the green mode. The driver stage provides a plurality of drive signals to a corresponding plurality of power stages in response to the trigger ramp signal when the multi-phase power converter is not in the green mode and to the on-time thresholds and the off-time thresholds when the multi-phase power converter is in the green mode.