All-Digital PD Controller for Voltage Stability and Fast Exit
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Solution Overview
Problem
Existing power supply generators and regulators face challenges in providing stable and fast power adjustments across a wide leakage load current range, especially during transitions between different power states, due to limitations in existing power management technologies like ACPI's C-states, which struggle with stability and efficiency.
Innovation Solution
The implementation of an all-digital proportional derivative (PD) controller for a voltage supply generator, which includes a mixed signal LDO regulator with power gates controlled by a digital PD mechanism, enabling faster state transitions and reduced leakage power consumption through adaptive voltage regulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If C6 ultra-low power state is used to eliminate leakage power, then leakage power savings are achieved, but Tentry and Texit times increase due to state copy and restore operations
Solution Approach 1:
The patent segments the power management into multiple hierarchical levels: C1 state for short stalls with fast exit, C6 state for long idle periods with ultra-low power, and intermediate states (C1LP, C2-C5) for gradual transitions. This segmentation allows the system to select the appropriate state based on stall duration predictions, optimizing both power savings and exit time performance.
Solution Approach 2:
The patent implements preliminary actions by pre-copying processor state to retention memory before entering C6 state, and pre-loading required state from retention memory before exiting C6 state. This preliminary preparation reduces the actual Tentry and Texit times by having data ready in advance, rather than performing copy operations during the state transition itself.
2Loss of time
If C1 Halt state is used for short stall periods, then Tentry and Texit times are minimized, but leakage power savings are not achieved
Solution Approach 1:
The patent implements dynamic power management where the system continuously monitors stall duration predictions and dynamically adjusts the power state selection. The power management unit can dynamically transition between C1, C1LP, C6, and intermediate states based on real-time conditions, making the power management strategy adaptive rather than static.
Solution Approach 2:
The patent changes the voltage and frequency parameters dynamically during state transitions. When transitioning from C6 to active state, the system gradually increases voltage and frequency rather than making abrupt changes, which stabilizes the processor core and reduces exit time while managing power consumption efficiently.
3Use of energy by stationary object
If voltage is reduced during low power mode, then power consumption is lowered, but voltage stability becomes challenging across wide leakage load current range
Solution Approach 1:
The patent implements a closed-loop feedback control system where the power management unit continuously monitors output voltage, input voltage, and load current conditions. Based on this feedback, the PMU dynamically adjusts the number of active power gates and modulation parameters to maintain stable output voltage despite variations in leakage load current and input voltage changes during state transitions.
Solution Approach 2:
The patent employs parameter changes by dynamically adjusting the duty cycle and switching frequency of power gates based on load conditions. The system modifies these parameters in real-time to maintain voltage stability across the wide range of leakage load currents that occur during different power states and transitions.
4Loss of time
If fast state transitions are implemented, then Texit time is reduced, but power supply stability during transitions becomes difficult to maintain
Solution Approach 1:
The patent uses periodic pulse-width modulation (PWM) to control power gates during state transitions. By applying periodic switching actions with controlled duty cycles, the system can rapidly adjust power delivery while maintaining average voltage stability, enabling fast transitions without sacrificing power supply stability.
Solution Approach 2:
The patent implements dynamic voltage scaling and frequency adjustment during state transitions. The system dynamically modifies voltage and frequency parameters in real-time based on the transition phase, allowing fast Texit times while maintaining stability through coordinated control of multiple power parameters rather than fixed static values.
Data Source
AI summary
An apparatus is provided which comprises: a plurality of devices coupled to an input power supply rail and an output power supply rail; a first circuitry coupled to the plurality of devices, wherein the first circuitry is to turn on or off one or more devices of the plurality according to a control; and a second circuitry coupled to the first circuitry, wherein the second circuitry comprises an all-digital proportional-derivative mechanism to generate the control according to a digital representation of voltage on the output power supply rail.