Mode Selection Circuit Using Multi-Functional Pin Clamping

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Solution Overview

Problem

Conventional control ICs require an additional structure and process for mode selection, increasing the start-up period due to the need for an internal current source connection to a specific pin, which is inefficient.

Innovation Solution

A mode selection circuit that generates a mode voltage using a clamping current and a multi-functional pin, allowing for mode selection without additional structures or processes, utilizing a comparator, clamping circuit, and current mirror circuit to control the connection and generate the mode voltage based on a passive element.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If an additional current source and connection structure are used for mode selection, then mode selection capability is improved, but device complexity and start-up period increase

Engineering Contradiction:

Improvemode selection capabilityVSAvoiddevice complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies multi-functionality by enabling a specific pin to serve both as a mode selection input and as a functional pin during normal operation. The mode selection is achieved by applying different voltages to this pin, which is integrated into the existing control IC structure without requiring separate dedicated pins or additional current sources, thus reducing device complexity while maintaining mode selection capability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the mode selection function with the existing pin structure of the control IC. Instead of using a separate structure for mode selection, the invention combines the mode selection capability with the functional pins already present in the converter circuit, eliminating the need for additional connection structures and current sources.

Inventive Principle:

Principle #5Merging (Combining)

2Adaptability or versatility

If an additional current source and connection process are used for mode selection, then mode selection capability is improved, but start-up period increases

Engineering Contradiction:

Improvemode selection capabilityVSAvoidstart-up period

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

The patent eliminates the need for preliminary connection actions during start-up by integrating the mode selection function into the pin voltage states that are already established during the normal start-up sequence. The mode is determined by the voltage level on the pin, which is naturally set during converter start-up without requiring additional connection steps or current source activation.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent extracts the mode selection function from the start-up process itself, using the existing voltage states on the pins during start-up to determine the operating mode. This eliminates the need for a separate mode selection phase or additional current source connection during start-up, thereby reducing the overall start-up period while maintaining full mode selection capability.

Inventive Principle:

Principle #2Taking out (Extraction)

3Reliability

If conventional mode selection with additional structure is used, then reliable mode selection is achieved, but ease of operation deteriorates

Engineering Contradiction:

Improvereliable mode selectionVSAvoidease of operation

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent improves ease of operation by using the same pin that would naturally be present in the circuit for functional purposes to also serve as the mode selection input. This eliminates the need for additional dedicated mode selection pins or complex connection procedures, making the converter easier to configure and operate while maintaining reliable mode selection through well-defined voltage thresholds.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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

Enables efficient mode selection without additional structures or processes, reducing the start-up period and improving operational efficiency by using a clamping current to generate the mode voltage through a multi-functional pin.

Implementation Method 1

a clamping circuit configured to clamp the voltage of the multi-pin to the clamping voltage when being connected to the multi-pin

Methodology Applied

Scientific EffectClamping:

Implementation Method 2

a comparator configured to compare the voltage of the multi-pin with a predetermined reference voltage

Methodology Applied

Scientific EffectVoltage comparison:

Implementation Method 3

a current mirror circuit configured to generate a mirror current by mirroring the clamping current and a resistor to which the mirror current flows, wherein the mode voltage is a voltage generated in the resistor

Methodology Applied

Scientific EffectCurrent mirroring:

Data Source

PatentUS9837909B2Mode selection circuit and switch control circuit including the mode selection circuit and multi functions pin

Publication Date: 2017.12.05 SEMICON COMPONENTS IND LLC

AI summary

A mode selection circuit generates a mode voltage according to a clamping current flowing when a voltage of a multi-pin is clamped to a predetermined clamping voltage, and selects one of a plurality of mode signals according to the mode voltage. The mode voltage is controlled according to a passive element connected to the multi-pin.