Switching Converter Input Current Detection via Duty Cycle Feedback

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Solution Overview

Problem

Existing switching converters face challenges in accurately detecting the magnitude of input current, which can lead to excessive current consumption, reducing the input voltage and causing abnormal operations in loads.

Innovation Solution

A device and method that includes a first switching converter generating a negative supply voltage, a load current sensor to sense the load current, and an input current detector to detect the input current based on the duty cycle and load current, allowing for accurate detection of input current magnitude and subsequent control to reduce excessive current consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If switching converter consumes excessive current, then power delivery to load is maintained, but input voltage is reduced causing abnormal operations

Engineering Contradiction:

Improvepower deliveryVSAvoidabnormal operations

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

The patent implements a feedback mechanism where the detected input current magnitude is fed back to the controller, which then adjusts the duty cycle of the switching converter to regulate current consumption and prevent input voltage drops that would cause abnormal load operations

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent replaces direct measurement of input current with an indirect measurement system that calculates input current magnitude based on the duty cycle and load current, eliminating the need for additional current sensors and simplifying the measurement mechanism

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If direct input current measurement is implemented, then accurate detection is achieved, but device complexity increases

Engineering Contradiction:

Improveinput current detection accuracyVSAvoiddetection system complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent uses the duty cycle signal as an intermediary parameter to infer input current magnitude. Instead of directly measuring input current, the system uses the relationship between duty cycle, load current, and power conservation to calculate the equivalent input current, thereby avoiding complex direct measurement circuits

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent creates a computational model that copies the electrical relationship between input current, duty cycle, and load current. By measuring easily accessible parameters (duty cycle and load current) and applying the power relationship formula, the system reconstructs the input current information without physical intrusion into the input current path

Inventive Principle:

Principle #26Copying

Data Source

PatentEP4290749A1Device and method for detecting magnitude of input current of switching converter

Publication Date: 2023.12.13 SAMSUNG ELECTRONICS CO LTD

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AI summary

A device including a first switching converter (11) configured to generate a negative supply voltage (Vss) based on an input voltage (VIN); a load current sensor (25) configured to sense a magnitude of a load current (ILOAD) passing through a load (5) to which the negative supply voltage (Vss) is provided; and a first input current detector (23) configured to detect a magnitude of a first input current (IIN1) provided to the first switching converter (11) based on a duty cycle of the first switching converter (11) and the magnitude of the load current (ILOAD).