Power Supply Manager Input Current Estimation

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Solution Overview

Problem

Conventional synchronous buck converters face inefficiencies due to energy dissipation as heat, making it challenging to accurately measure input current and power supply efficiency, which is essential for health/status information and circuit performance.

Innovation Solution

A power supply manager estimates input current by multiplying output current with duty cycle values, allowing for the derivation of input power and efficiency without the need for complex measuring circuitry, using readily available control and feedback information.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional physical measurement methods (series resistor) are used to measure input current, then measurement capability is achieved, but power losses increase and measurement precision deteriorates

Engineering Contradiction:

Improveinput current measurement accuracyVSAvoidpower loss in series resistor

Core Design Contradiction:

Measurement precisionVSLoss of energy

Solution Approach 1:

The patent introduces an intermediary approach by using the relationship between output current and duty cycle as a mediator to estimate input current, rather than directly measuring it with a physical series resistor. This indirect measurement method avoids the power losses and precision issues of direct measurement while still providing accurate input current information through the formula: input current ≈ output current × duty cycle

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the mechanical/physical measurement system (series resistor with voltage measurement) with a computational system that calculates input current based on readily available output current and duty cycle information. This substitution eliminates the need for additional physical measurement components and their associated power losses

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Difficulty of detecting and measuring

If series resistor measurement method is used, then input current can be detected, but device complexity increases

Engineering Contradiction:

Improveinput current detection capabilityVSAvoidcircuit complexity for measurement

Core Design Contradiction:

Difficulty of detecting and measuringVSDevice complexity

Solution Approach 1:

The patent applies the self-service principle by utilizing information (output current and duty cycle) that is already available within the power supply control system to derive input current. This eliminates the need for separate measurement circuits, sensors, or additional components, as the system uses its own existing data to achieve the measurement capability

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent makes the existing control parameters (output current and duty cycle) serve multiple functions: they control the power conversion process and simultaneously provide the data needed for input current estimation. This multi-functionality eliminates the need for dedicated measurement infrastructure

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Loss of energy

If efficient power conversion is achieved, then energy loss is reduced, but measurement of efficiency becomes more difficult

Engineering Contradiction:

Improvepower supply efficiencyVSAvoidefficiency measurement difficulty

Core Design Contradiction:

Loss of energyVSDifficulty of detecting and measuring

Solution Approach 1:

The patent uses the duty cycle as an intermediary parameter that connects output measurements to input measurements. By multiplying output current by duty cycle, the system obtains an accurate estimate of input current, which then enables efficiency calculation without requiring direct input measurement hardware

Inventive Principle:

Principle #24Intermediary (Mediator)

4Reliability

If health status monitoring is implemented, then reliability information is provided, but cost and complexity increase

Engineering Contradiction:

Improvehealth status informationVSAvoidmonitoring system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The health status monitoring system uses the same existing control parameters (output current, duty cycle) that are already being used for power conversion control. By deriving input current and efficiency from these existing parameters, the system provides comprehensive health monitoring without adding separate sensors, measurement circuits, or monitoring infrastructure

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS8024138B2Power supply circuitry, collection and reporting of power supply parameter information

Publication Date: 2011.09.20 INFINEON TECHNOLOGIES AMERICAS CORP

AI summary

In an example configuration, a power supply manager receives an output current value representing an amount of output current supplied by one or more power converter phases to a load. The power supply manager also receives a duty cycle value representing a duty cycle for controlling operation of the at least one power converter phase. The power supply manager produces an estimate of input current supplied to the power supply circuit based at least in part on multiplying the output current value by the duty cycle value. Contrary to conventional methods such as physically measuring an input current using complex measuring circuitry, embodiments herein include utilizing parameter information such as output current information and duty cycle information to deduce an amount of input current.