Voltage Regulator VID Transient Response Control
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Solution Overview
Problem
Voltage regulators struggle to meet the settling time specification during CPU voltage identification (VID) transients, leading to potential CPU damage or performance degradation due to non-linear changes in output voltage during rapid VID changes.
Innovation Solution
A method and circuit structure for a voltage regulator that includes an inductor current sensor, a sample and hold module, and a pulse width modulation comparator, which senses the inductor current, samples the current sense signal in steady states, holds the sampling result during VID transients, and uses the droop control signal to generate a pulse width modulation signal for regulating the output voltage, thereby isolating the VID chasing speed from inductor current changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the voltage regulator uses adaptive voltage position (AVP) system to regulate output voltage, then the voltage regulator can provide droop control signal according to sensed inductor current, but the inductor current changes during VID transient cause non-linear changes in output voltage and extend settling time beyond specification
Solution Approach 1:
The patent applies preliminary action by detecting the VID transient state in advance and preemptively adjusting the droop control signal generation. When a VID transient is detected, the system switches to a linear control mode that ignores inductor current variations, preparing the output voltage control ahead of time to meet the settling time specification. This is achieved by monitoring VID changes and dynamically switching between AVP and linear control modes.
Solution Approach 2:
The patent implements dynamics by making the control system adaptive and changeable based on operating conditions. The droop control signal generation is dynamically adjusted: during steady-state, the system uses AVP with inductor current sensing; during VID transients, it switches to linear control without inductor current influence. This dynamic switching between control modes allows the system to optimize performance for different operational phases.
2Speed
If the voltage regulator responds quickly to VID changes to improve VID chasing speed, then the CPU performance can be maintained, but the output voltage may become unstable and potentially damage the CPU if settling time is not met
Solution Approach 1:
The patent applies dynamics by implementing a dynamic control mode switching mechanism that adapts the control strategy based on the operational phase. During VID transients, the system switches to a fast-response linear control mode that prioritizes VID chasing speed while maintaining stability. The control system dynamically adjusts the droop control signal generation to ensure both rapid response and output voltage stability, preventing CPU damage while maintaining performance.
Solution Approach 2:
The patent implements feedback by continuously monitoring the output voltage and VID status to detect transient conditions. The system uses feedback from the VID change detection to trigger appropriate control responses. When VID transients are detected, the feedback mechanism activates the linear control mode, which provides stable voltage regulation during the transition, ensuring CPU safety while maintaining fast VID chasing capability.
3Reliability
If the voltage regulator uses inductor current sensing to generate droop control signal, then the voltage regulation can be achieved, but the extra increase or decrease of inductor current during VID transient causes current sense signal to change and extends settling time
Solution Approach 1:
The patent applies preliminary action by detecting VID transient conditions in advance and preemptively modifying the droop control signal generation strategy. When a VID transient is anticipated or detected, the system switches to linear control mode before the transient fully impacts the output voltage. This preliminary switching prevents the inductor current variations from causing non-linear output voltage changes, ensuring the settling time remains within specifications.
Solution Approach 2:
The patent applies the taking out principle by extracting or removing the inductor current sensing function from the droop control signal generation during VID transient periods. By selectively disabling or bypassing the inductor current influence on the droop control signal during transients, the system eliminates the source of non-linear output voltage changes. This extraction allows the system to maintain voltage regulation during steady-state while achieving fast settling during transients.
Data Source
AI summary
An exemplary method for improving voltage identification (VID) transient response is adapted to a voltage regulator and includes steps of: continuously sensing an inductor current of the voltage regulator to thereby output a current sense signal; during a steady state operation period, sampling the current sense signal to thereby obtain a sampling result for providing a droop control signal; after entering a VID transient period from the steady state operation period, holding the sampling result for providing the droop control signal; and taking the droop control signal as a consideration factor of producing a pulse width modulation signal to regulate an output voltage of the voltage regulator.