Digital Duty Cycle Controller for GPU Power Management

Solution Overview

Problem

Analog duty cycle controllers for switching mode power supplies face challenges in efficiently managing transients and responding to load changes due to the need for operational amplifiers and comparators, which occupy valuable space and result in delays and overshooting or undershooting of output voltage, especially when controlling GPUs.

Innovation Solution

A digital duty cycle controller that calculates a base duty cycle and a dynamic offset duty cycle using a power management unit within a high-speed processing unit, incorporating a voltage sensor and analog-to-digital converter to sample feedback voltages and apply a transfer function, with a pulse-width modulator to modulate the duty cycle, allowing for on-die feedback sensing and continuous sampling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an analog control circuit is used to control transients, then the control circuit can be implemented with operational amplifiers and comparators, but the circuit takes up valuable layout space and may result in overshooting or undershooting of output voltage

Engineering Contradiction:

Improvecontrol accuracyVSAvoidlayout space

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The patent replaces the analog control circuit (operational amplifiers and comparators) with a digital control circuit implemented within the GPU's power management unit. This substitution eliminates the need for discrete analog components, reducing layout space while maintaining control accuracy through digital processing of feedback signals and duty cycle calculations.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent merges the power management control functions directly into the GPU's power management unit, integrating the duty cycle controller within the processing unit itself. This consolidation eliminates separate analog control circuits and their associated components, reducing overall layout space while improving response time by enabling direct sensing and control within the GPU.

Inventive Principle:

Principle #5Merging (Combining)

2Ease of operation

If an analog duty cycle controller is used, then the controller can be implemented externally, but it exhibits significant delay in response as the analog components cannot be integrated within the GPU

Engineering Contradiction:

Improveimplementation flexibilityVSAvoidresponse delay

Core Design Contradiction:

Ease of operationVSLoss of time

Solution Approach 1:

The patent merges the power management control functions directly into the GPU's power management unit, integrating the duty cycle controller within the processing unit itself. This consolidation eliminates separate analog control circuits and their associated components, reducing overall layout space while improving response time by enabling direct sensing and control within the GPU.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent replaces the analog control circuit (operational amplifiers and comparators) with a digital control circuit implemented within the GPU's power management unit. This substitution eliminates the need for discrete analog components, reducing layout space while maintaining control accuracy through digital processing of feedback signals and duty cycle calculations.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Difficulty of detecting and measuring

If an analog control circuit is used, then the circuit can sense feedback voltages, but it cannot be integrated within the GPU core and exhibits significant delay

Engineering Contradiction:

Improvefeedback sensing capabilityVSAvoidresponse delay

Core Design Contradiction:

Difficulty of detecting and measuringVSLoss of time

Solution Approach 1:

The patent merges the power management control functions directly into the GPU's power management unit, integrating the duty cycle controller within the processing unit itself. This consolidation eliminates separate analog control circuits and their associated components, reducing overall layout space while improving response time by enabling direct sensing and control within the GPU.

Inventive Principle:

Principle #5Merging (Combining)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This solution enables faster and more accurate control of duty cycles, reducing transient deviations and improving the performance and integrity of loads like GPUs by leveraging digital processing and on-die feedback, thus overcoming the limitations of analog controllers.

Implementation Method 1

sensing analog feedback voltages of the high-speed processing unit using a voltage sensor

Methodology Applied

Scientific EffectVoltage sensing: Electric Field

Implementation Method 2

converting the number of analog feedback voltages to digital voltage signals using an analog to digital converter

Methodology Applied

Scientific EffectAnalog to digital conversion:

Data Source

PatentUS9086707B2System and method for modulating a duty cycle of a switching mode power supply

Publication Date: 2015.07.21 NVIDIA CORP

AI summary

Disclosed are methods, devices, and systems to digitally control a duty cycle of a switching mode power supply. In one embodiment, a method comprises calculating a base duty cycle using a power management unit of a high-speed processing unit, calculating a dynamic offset duty cycle using the power management unit to apply a transfer function to a sampled feedback voltage signal, and adding the base duty cycle to the dynamic offset duty cycle to obtain a duty cycle of the switching mode power supply. A system comprises a switching mode power supply, a power management unit, a voltage sensor, and an analog to digital converter all embedded within a high-speed processing unit, and a pulse-width modulator coupled between the switching mode power supply and the high-speed processing unit to modulate the duty cycle of the switching mode power supply.