An optical coupler, also known as an opto-isolator or optocoupler, is a device that transfers electrical signals using light. It typically consists of an infrared LED (light source) and a photodetector (such as a phototransistor) housed in the same package. When an input signal is applied, the LED emits light, which is then detected by the photodetector, generating a corresponding current at the output. This process enables the conversion from "electrical to optical to electrical." Most standard optocouplers are designed for digital (switching) signals only and are not suitable for analog signal transmission. However, linear optocouplers, introduced more recently, can handle continuously varying analog or current signals, expanding their use in various applications.
Optocouplers come in different types and packages, including dual-in-line, tubular, and fiber-optic configurations. Common models include general-purpose types, Darlington transistors, high-speed variants, optical integrated circuits, and specialized devices like photosensitive thyristors or field-effect transistors. These components are widely used in signal isolation, level shifting, power supplies, and communication systems due to their electrical isolation, noise immunity, and long lifespan.
One key parameter of an optocoupler is the Current Transfer Ratio (CTR), which measures the efficiency of signal transfer between the input and output. For standard optocouplers, CTR typically ranges from 20% to 300%, while linear optocouplers offer better linearity, making them ideal for analog applications. The CTR-IF curve of a linear optocoupler remains relatively stable across a range of input currents, allowing for accurate signal transmission. In contrast, standard optocouplers exhibit significant nonlinearity, especially at low input currents, making them unsuitable for analog use.
When selecting a linear optocoupler for a switching power supply, it's important to consider factors such as CTR range, response time, and linearity. A CTR between 50% and 200% is generally recommended to ensure stable operation and prevent false triggering. Models like the 4N25 or 4N35 are commonly used but are better suited for digital signals. For precise voltage regulation, linear optocouplers like the CNY17-2, combined with a precision shunt regulator such as the TL431C, are often used in feedback circuits.
A practical example involves a multi-output power converter with inputs ranging from 36V to 90V and outputs of +5V, +15V, and -15V. This design uses a monolithic switching IC (TOP104Y) and includes a feedback loop using a linear optocoupler and a precision voltage reference. Additional components like Schottky diodes, ultra-fast recovery diodes, and a transient voltage suppressor help improve efficiency and protect the circuit from voltage spikes. This setup achieves a total efficiency of 75% to 80%, demonstrating the effectiveness of optocouplers in modern power electronics.
Power Wall Battery
The Power Wall Battery is a high-performance home battery solution from Keylewatt. The following is a detailed description of its class purpose:
I. Product overview
Keylewatt, Powerwall is a Battery Energy Storage System designed for the home, designed to provide a reliable reserve of electricity for the home by storing electricity generated by solar panels or electricity from the grid. Not only can it provide power at night or when the weather is bad, it can also serve as a backup power source to ensure that the home power supply is not affected in the event of a power outage.
Two, the main characteristics
High energy storage density:
The Powerwall is capable of storing large amounts of electricity in a small design to meet the daily electricity needs of the home.
Advanced Battery technology:
Advanced battery technology for longer life and higher efficiency.
From the first generation to the third generation, the battery technology of the Powerwall has been continuously upgraded, such as the use of 21700 cells, integrated solar inverters, etc., to further improve the overall performance of the system.
Intelligent control function:
The Powerwall is equipped with an intelligent control system that automatically monitors the status of the battery and charges and discharges it as needed.
Users can remotely monitor and manage the working status of the Powerwall through a mobile app or web interface.
Multiple application scenarios:
The Powerwall is not only suitable for home use, but also for commercial and industrial applications.
At peak times, the Powerwall can release stored electricity and reduce the load on the grid.
At the same time, it can also be used as a charging pile for Tesla vehicles to provide charging services for electric vehicles.
Environmental protection and Sustainable development:
By storing electricity generated from renewable sources such as solar, Powerwall reduces reliance on traditional energy sources, helping to lower carbon emissions and protect the environment.
It promotes the energy transition and the development of renewable energy, in line with the concept of sustainable development.
Power storage battery system, solar system with power battery, commercial and industrial system
Foshan Keylewatt Technology Co., LTD , https://www.klwenergy.com