Injection Locked Phasing for High Duty Cycle Multiphase Regulators
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Solution Overview
Problem
Existing multiphase current mode buck switchers face limitations at duty cycles above 30% due to interactions between PLL tuning and voltage loop, resulting in compromised transient response and phase separation, and require additional slope compensation which does not fully address the issue.
Innovation Solution
An injection locked phasing system that operates multiphase regulators out of phase with each other, enabling efficient operation at higher duty cycles without tuning, and allowing for smaller output filters and improved load transient performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If traditional PLL tuning is used in multiphase regulators, then phase synchronization is achieved, but transient response and phase separation are compromised at duty cycles above 30%
Solution Approach 1:
The patent introduces an injection-locked phase detector as an intermediary component between the VCO and the phase control system. This detector compares the phase of the feedback signal with a reference signal and generates correction signals that adjust the VCO phase, enabling accurate phase synchronization without compromising transient response even at duty cycles above 30%.
Solution Approach 2:
The patent implements a feedback mechanism where the output of the multiphase regulator is fed back through a divider to the injection-locked phase detector. The detector continuously monitors phase differences and generates corrective signals to the VCO, maintaining phase synchronization dynamically across varying duty cycles and load conditions.
2Power
If duty cycle is increased above 30% in traditional multiphase regulators, then power delivery capability is improved, but phase separation and transient response deteriorate
Solution Approach 1:
The patent employs dynamic phase adjustment through the injection-locked phase detector and VCO system. The phase relationship between multiphase signals is continuously adapted based on real-time feedback, allowing the system to maintain optimal phase separation across a wide range of duty cycles from 30% to 100%, enabling high power delivery without sacrificing phase control.
3Reliability
If slope compensation is added to multiphase regulators, then transient response is partially improved, but the fundamental issue of phase separation at high duty cycles remains unresolved
Solution Approach 1:
The patent replaces the mechanical approach of slope compensation with an electronic phase control mechanism. Instead of adding compensatory signals to the ramp generator, the system uses an injection-locked phase detector to electronically adjust the phase of the VCO output, achieving superior transient response and phase separation with a more elegant and controllable solution.
Data Source
AI summary
A system and method capable of injection locking the phases of a peak-valley multiphase regulator includes comparing an output voltage error signal with a ramp control signal and providing a corresponding slope reset signal, using transitions of the slope reset signal to develop a equally spaced high side ramp signals and equally spaced low side ramp signals, and injecting a corresponding one of the high side signals and a corresponding one of the low side ramp signals into each of the phases which correspondingly develop equally spaced pulse control signals for multiphase operation. Such injection locking allows the additional phases to operate out of phase with the first phase and allows operation at high duty cycles.