Monolithic Bus Slave Circuit for Emergency Lighting
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Solution Overview
Problem
Existing bus networked emergency evacuation light slave circuits require multiple expensive integrated chips and discrete devices, leading to high costs, poor reliability, and low energy efficiency due to the need for DC/DC voltage conversion and constant voltage drive systems, which result in uneven LED brightness and significant energy wastage.
Innovation Solution
A monolithic bus slave circuit structure incorporating a monolithic integrated chip with a rectifier bridge, light circuits, and energy storage capacitors, enabling intelligent constant current drive and fault detection, reducing the reliance on external chips and improving energy efficiency by using a single integrated solution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple integrated chips (DC/DC voltage conversion chip, LDO chip, MCU chip) and discrete devices are used to build the slave circuit, then the system can achieve voltage conversion and control functions, but the system cost increases, reliability decreases, and anti-interference ability weakens
Solution Approach 1:
The patent merges the DC/DC voltage conversion function, LDO voltage regulation function, and MCU control function into a single monolithic integrated chip. This consolidation eliminates the need for multiple separate chips and discrete devices, thereby reducing system complexity, improving reliability, and enhancing anti-interference capability while maintaining all necessary voltage conversion and control functions.
Solution Approach 2:
The monolithic integrated chip is designed to perform multiple functions simultaneously: it includes a DC/DC voltage conversion module for step-down conversion, an LDO voltage regulation module for precise voltage output, and an MCU module for communication and control. This multi-functional design allows a single chip to replace multiple specialized components, simplifying the system architecture.
2Ease of manufacture
If constant voltage drive (VCC=12V) with resistor R4 is used to achieve constant current for LEDs, then the circuit implementation is simple, but energy efficiency decreases (16.7% energy wasted on resistor) and LED brightness uniformity deteriorates due to large voltage drop differences between LEDs
Solution Approach 1:
The patent changes the control parameter from constant voltage (VCC=12V) to constant current control. The monolithic integrated chip directly controls the LED driving current through its internal current regulation circuitry, eliminating the need for external current-limiting resistors. This parameter change from voltage control to current control significantly improves energy efficiency by eliminating the I²R power loss in resistors while maintaining uniform LED brightness despite variations in LED forward voltage drops.
3Stability of the object's composition
If DC/DC voltage conversion integrated chip is used to maintain stable 12V output when input voltage varies from 16V to 36V, then voltage stability is improved, but system cost increases due to expensive specialized chips
Solution Approach 1:
The patent combines the DC/DC voltage conversion functionality with other control functions into a monolithic integrated chip. By integrating the voltage conversion module within the same chip that also contains the LDO and MCU, the system eliminates the need for expensive external DC/DC conversion chips, thereby reducing system cost while maintaining stable voltage output across the input range of 16V to 36V.
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 monolithic bus slave circuit achieves uniform LED brightness, flexible LED adjustment, and high energy efficiency while simplifying the system design, reducing costs, and enhancing reliability and anti-interference capabilities.
Implementation Method 1
both the bus voltage input pin and the ground pin are connected to an output end of the rectifier bridge, two input ends of the rectifier bridge are connected to a positive line and an negative line of a bus respectively
Implementation Method 2
the power output pin is connected to one end of an energy storage capacitor, and the other end of the energy storage capacitor is grounded
Implementation Method 3
An emergency evacuation light includes three groups of light-emitting diodes (LEDs), and three groups of LEDs can light up the left arrow, the right arrow, and the middle human figure respectively
Data Source
AI summary
A monolithic bus slave circuit structure is provided, including: a monolithic integrated chip, a rectifier bridge, a first light circuit, a second light circuit, and a third light circuit. The monolithic integrated chip includes a bus voltage input pin, a ground pin, a first drive signal output pin, a second drive signal output pin, a third drive signal output pin, and a power output pin. Both the bus voltage input pin and the ground pin are connected to an output end of the rectifier bridge, two input ends of the rectifier bridge are connected to a positive line and an negative line of a bus respectively, the ground pin is grounded. The monolithic bus slave circuit structure realizes the intelligent constant current drive function and drive the light circuits with constant current in the voltage range of the whole bus, which does not depend on the parameters of the LEDs.