Analyze the LED drive precision control method to improve drive efficiency

When it comes to LED driver accuracy, constant current error is usually thought of. In fact, the drive accuracy is not limited to current accuracy. LEDs are a typical current-driven device that precisely controls the LED drive current and determines many parameters including light efficiency, power efficiency, heat dissipation, and product brightness. Driving the LED is mainly to control its current. Whether it is directly increasing or decreasing the drive current, or the duty cycle (PWM) reduces the switching time ratio, it is the control current mode, but the purpose is not the same. This article will explain the differences between different drivers in different applications.

Introduction to distributed constant current drive principle

In the past incandescent and energy-saving lamps market, LEDs have become a mainstream lamp type with limited specifications, and it is difficult for LEDs to continue to comply. LEDs have the flexibility of application and will bring more power specifications in future designs. We have to avoid too many power supply specifications and do not bring many obstacles to mass production in the future. Based on the idea of ​​not limiting design flexibility while also taking into account as few power supply design specifications as possible, we propose a distributed constant current architecture.

The principle of distributed constant current is to establish independent constant current sources at each parallel branch point to manage, maintain and control the stability of branches and branches, branches and overall lines. The distributed constant current circuit can be regarded as a complete line structure in use, and the practical application is distributed in each node of the line, which is a circuit structure that can be controlled by constant current and can communicate with each other. Distributed constant current design LED products have very high product stability and unique design advantages.

At present, LED products claim a big gap with the actual service life. In the case where the accumulation of drive line design technology is limited, the actual service life is measured by the method of evaluating the life of the product, which is easy to cause errors. The stability of the drive line will directly affect the overall stability of the product.

The reason why the distributed constant current technology has high reliability is that the AC power supply section continues to use the conventional switching power supply, and the constant voltage power supply mode is adopted. The accumulation of switching power supply technology will create quality conditions for LED power supply design. Under the same power supply specification, it is no longer necessary to develop a new power supply model, the power can be backward compatible, greatly reducing power supply specifications and improving power supply uniformity.