Semiconductor Current Sense Amplifier with Feedback Paths

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Solution Overview

Problem

Current LED lamp modules face challenges in maintaining high current sense accuracy and protecting electrostatic protection diodes due to the external connection of current-limiting resistors, which leads to increased costs and component size, and introduces temperature drift and accuracy issues.

Innovation Solution

The integration of a current sense amplifier with feedback current paths and a V-I converter, along with the use of current-limiting resistors connected externally to the SNSP and SNSN pins, helps to eliminate gain errors and temperature drift, while also protecting electrostatic protection diodes without the need for additional surge protection diodes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If current-limiting resistors are connected externally to protect electrostatic protection diodes, then reliability is improved, but device complexity and cost increase

Engineering Contradiction:
Improveprotection of electrostatic protection diodesVSAvoidnumber of external components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines multiple functions into the integrated circuit: current sensing, current limiting, and electrostatic protection. The current sense amplifier integrates the sensing function, while the control circuit integrates both current limiting and protection functions, eliminating the need for separate external components for each function.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The control circuit is designed to perform multiple functions simultaneously: it controls the current limiting operation during normal operation and also provides protection during surge conditions. This multi-functional design replaces what would traditionally require separate dedicated components for each function.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If current-limiting resistors are connected externally, then reliability is improved, but manufacturing cost increases

Engineering Contradiction:
Improveprotection of electrostatic protection diodesVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent combines multiple functions into the integrated circuit: current sensing, current limiting, and electrostatic protection. The current sense amplifier integrates the sensing function, while the control circuit integrates both current limiting and protection functions, eliminating the need for separate external components for each function.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If current-limiting resistors are connected externally, then reliability is improved, but component size increases

Engineering Contradiction:
Improveprotection of electrostatic protection diodesVSAvoidmodule size
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The patent combines multiple functions into the integrated circuit: current sensing, current limiting, and electrostatic protection. The current sense amplifier integrates the sensing function, while the control circuit integrates both current limiting and protection functions, eliminating the need for separate external components for each function.

Inventive Principle:
Principle #5Merging (Combining)

4Measurement precision

If current sense amplifier is used with feedback paths, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improvecurrent sense accuracyVSAvoidcircuit configuration
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent implements feedback current paths that connect the output of the current sense amplifier back to its inputs. This feedback mechanism allows the amplifier to compensate for its own offset voltages and gain errors, significantly improving measurement precision. The feedback paths are integrated into the amplifier circuit itself, managing complexity through systematic design.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent employs techniques to eliminate offset voltages and adjust gain parameters through the feedback paths. By dynamically adjusting the electrical parameters of the amplifier based on feedback signals, the system achieves high precision current sensing while managing circuit complexity through parameter optimization rather than additional components.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS20250016896A1Semiconductor device and module
Publication Date: 2025.01.09 ROHM CO LTD
  • US20250016896A1 patent drawing
  • US20250016896A1 patent drawing
  • US20250016896A1 patent drawing

AI summary

A semiconductor device includes: a current sense circuit that generates a current sense signal corresponding to a monitoring target current; an error amplifier; a comparator; and a controller. The current sense circuit includes: a differential amplifier of a current output type; a first input resistor connected between a first input terminal of the differential amplifier and a first current sense terminal; a second input resistor connected between a second input terminal of the differential amplifier and a second current sense terminal; an output resistor configured to be connected to the output terminal of the differential amplifier; a first feedback current path across which a first feedback current is passed between the first input terminal and the output terminal of the differential amplifier; and a second feedback current path across which a second feedback current is passed between the second input terminal of the differential amplifier and the output terminal.