Digital Latch Control Circuit for Over-Voltage Protection

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Solution Overview

Problem

Conventional power converters with over-voltage protection schemes face issues with noise sensitivity due to high impedance analog circuits, leading to erroneous operations and increased production costs from the need for additional de-glitch circuits and startup current.

Innovation Solution

A digital latch control circuit is introduced, utilizing a complementary switch unit, resistor unit, and control module to latch the supply voltage at a predetermined level, disabling the voltage converting circuit during over-voltage conditions, and incorporating a variable resistor for noise immunity and reduced impedance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional analog circuits with high impedance nodes are used for over-voltage protection, then the circuit can detect and respond to over-voltage conditions, but the high impedance makes the circuit highly sensitive to noise causing erroneous operations

Engineering Contradiction:

Improveover-voltage protection reliabilityVSAvoidnoise sensitivity

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the conventional analog circuit implementation with a digital latch control circuit. The digital circuit uses discrete logic levels and latch states instead of continuous analog voltage levels, making it inherently more immune to noise. The digital approach substitutes analog impedance-based detection with digital logic-based state machine control, eliminating the noise sensitivity issue while maintaining over-voltage protection functionality.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the operating parameters of the control circuit from high-impedance analog voltage levels to low-impedance digital logic levels. By transforming the circuit operation from analog to digital domain, the impedance parameters are fundamentally changed, resulting in noise immunity without sacrificing protection reliability.

Inventive Principle:

Principle #35Parameter changes

2Object-affected harmful factors

If de-glitch circuits are added to reduce noise sensitivity, then erroneous operations are reduced, but production costs increase and circuit area increases

Engineering Contradiction:

Improvenoise sensitivityVSAvoidcircuit complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent eliminates the need for separate de-glitch circuits by substituting the entire analog control system with a digital latch control system. The digital architecture inherently provides noise immunity without requiring additional de-glitching components, thereby reducing circuit complexity and production costs while maintaining robust noise performance.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent extracts and removes the need for de-glitch circuits from the overall system design. By adopting digital logic levels and latch-based control, the functionality that would have required separate de-glitch circuits is inherently built into the digital control architecture, simplifying the overall circuit design.

Inventive Principle:

Principle #2Taking out (Extraction)

3Object-affected harmful factors

If de-glitch circuits are added to reduce noise sensitivity, then erroneous operations are reduced, but additional startup current is required

Engineering Contradiction:

Improvenoise sensitivityVSAvoidstartup current

Core Design Contradiction:

Object-affected harmful factorsVSUse of energy by moving object

Solution Approach 1:

The patent replaces the analog de-glitch circuit requirement with a digital control architecture that does not require additional startup current. The digital latch circuit is designed to operate efficiently without the continuous current consumption that analog de-glitch circuits would require, reducing overall energy usage during startup and operation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Ease of operation

If analog transistors are used as switches in over-voltage protection, then the circuit can control power flow, but the high impedance nodes create noise susceptibility

Engineering Contradiction:

Improvepower flow controlVSAvoidnoise sensitivity

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent substitutes analog transistor switching with digital latch-based control. The digital control signals drive power switches (such as MOSFETs or IGBTs) in a controlled manner based on digital logic states rather than analog voltage levels. This substitution maintains effective power flow control while eliminating the high-impedance noise-sensitive nodes inherent in analog transistor control circuits.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS7773394B2Digital latch control circuit for over-voltage protection and power converter using the control circuit

Publication Date: 2010.08.10 LEADTREND TECH

AI summary

An AC/DC power supply with over-voltage protection includes a voltage converting circuit and a digital latch control circuit. The voltage converting circuit has a first-side winding, a second-side winding, and an auxiliary winding for providing a supply voltage according to the AC input voltage. The digital latch control circuit is coupled to the voltage converting circuit and utilized for latching a voltage level of the supply voltage at a first predetermined level according to an over-voltage protection (OVP) trigger signal, where the voltage converting circuit is disabled when the voltage level is latched at the first predetermined level.