Power Supply Current Balancing via Digital Detection and Voltage Compensation

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Solution Overview

Problem

Current balancing mechanisms in redundant power supply systems for high-end server systems suffer from errors in current sampling and amplification, leading to inefficiencies, reliability issues, temperature sensitivity, and phase latency, limiting maximum output power.

Innovation Solution

A power supply device with a current balancing mechanism that includes a current detecting unit, a comparator unit, a current mirror unit, and a voltage compensation unit, utilizing a current mirror circuit and PWM signal filtering to correct sample voltage and provide accurate current share voltage, independent of temperature changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If an analog current detecting unit with amplifier is used to sample output current, then current sharing information can be generated, but measurement precision deteriorates due to sampling and amplification errors reaching 6.9%

Engineering Contradiction:

Improvecurrent sharing information accuracyVSAvoidcurrent balancing reliability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent replaces the analog current detecting unit with a digital current detecting unit that uses PWM (pulse width modulation) to represent current information. This substitution eliminates the analog sampling and amplification processes that introduced errors, achieving both high measurement precision and reliability without the 6.9% error margin inherent in analog systems.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If a digital current detecting unit with PWM is used to generate current information, then measurement precision improves, but loss of time increases due to phase delay and latency in PWM modulation

Engineering Contradiction:

Improvecurrent information accuracyVSAvoidphase delay and latency

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent extracts and removes the PWM modulation stage from the current detecting unit, directly outputting digital current information without time-consuming modulation. This eliminates the phase delay and latency inherent in PWM-based systems while maintaining the high precision benefits of digital detection.

Inventive Principle:

Principle #2Taking out (Extraction)

3Ease of operation

If BJT or MOSFET variable resistors are added to the amplifier unit, then ease of operation improves by eliminating manual adjustment, but stability deteriorates due to temperature sensitivity

Engineering Contradiction:

Improveautomatic adjustment capabilityVSAvoidtemperature stability

Core Design Contradiction:

Ease of operationVSStability of the object's composition

Solution Approach 1:

The patent replaces the temperature-sensitive BJT/MOSFET variable resistors with a digital current detecting unit that uses digital-to-analog conversion. This substitution eliminates components whose characteristics change with temperature, achieving automatic operation without sacrificing thermal stability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

The solution achieves precise current balancing with reduced errors and phase latency, ensuring stable and efficient power distribution across power supply devices, even under varying load conditions.

Implementation Method 1

The current mirror unit has a first end and a second end. The first end is connected to the sample voltage output end of the current detecting unit, and the second end is connected to the positive input end of the comparator unit

Methodology Applied

Scientific EffectCurrent mirror effect:

Implementation Method 2

The voltage compensation unit is connected to the first end of the current mirror unit, and provides a compensation voltage to the first end of the current mirror unit

Methodology Applied

Scientific EffectVoltage compensation:

Implementation Method 3

The comparator unit has a positive input end, a negative input end, and a current share output end. The positive input end is connected to the sample voltage output end through a voltage divider unit, and the negative input end is connected to the current share output end through a negative feedback unit

Methodology Applied

Scientific EffectVoltage comparison:

Data Source

PatentUS11322937B2Power supply device with improved current balancing mechanism

Publication Date: 2022.05.03 ACBEL POLYTECH INC

AI summary

A power supply device with improved current balancing mechanism includes a power supply module, and a current detecting module detecting the output current to generate a sample voltage. A compensation voltage is provided that is in superposition with the sample voltage to synthesizes a corrected sample voltage, and a current mirror unit receives the corrected sample voltage at a first end. A positive input end of a comparator unit is connected to a second end of the current mirror unit, and is connected to the first end through a voltage divider, while the comparator unit outputs the current share voltage under negative feedback control. The current share output is corrected by compensating the sampling voltage and reflecting it by a current mirror with a certain ratio, the inconvenience of manually adjusting variable resistor, or the problem of temperature influenced BJT and MOSFET, or phase delay of digital sampling is solved.