Power management solutions are crucial to LED energy saving

For energy-saving reasons, the industry requires that the brightness of LEDs be adjusted. Using PWM (pulse width modulation) is an effective dimming method. However, with traditional PWM chips, each set of image data must first be converted into a PWM control signal, which results in a high workload on the controller. Macroblock Technology uses a built-in S-PWM method to effectively reduce the burden on the controller.

S-PWM is a patented technology of Macroblock Technology. It improves the function of traditional PWM, disperses the on-time of the image into several shorter on-time segments, increases the refresh rate and reduces the flickering feeling while maintaining the same brightness. At the same time, the built-in S-PWM chip can transmit the image data directly to the chip without conversion operations, which increases the number of load points of the controller, reduces the number of controllers in the system, and thus reduces costs. In addition, the use of S-PWM driver chips can also improve LED utilization, reduce system transmission frequency and EMI (electromagnetic interference). It is a general trend to have built-in PWM in the chip, because built-in PWM will comprehensively improve the image quality of LED color screens. Whether it is high-level or low-level color screens, dynamic screens or scanning screens, PWM chips can be used, and the refresh rate can be increased. The constant current LED driver MBI5040 launched by Macroblock Technology for high-level LED display applications is an example of using a built-in S-PWM chip.

To improve LED efficiency, it is usually necessary to start from three aspects: optical design, driver design and heat dissipation management. It can be seen that for LED lighting applications, the choice of power management solution is also very important for energy saving, which requires the selection of the most suitable AC-DC driver in the driver design. Although the common two-stage AC-DC driver has the advantages of a wide variety of products and simple application, its efficiency is difficult to meet the increasingly stringent requirements of energy-saving products. The efficiency of the common two-stage AC-DC driver power supply unit is 85%. If it is matched with a constant current IC with an efficiency of 90%, the overall efficiency is only 76%.

The buck-type, high-efficiency AC-DC LED control chip MBI6901 launched by Macroblock Technology provides a cost-effective solution for lighting system designers. The solution adopts a hysteresis frequency modulation architecture, which can effectively improve the conversion efficiency of the power supply under light load. For example, in a 110V power supply system, taking 350mA driving more than 6 LEDs as an example, the efficiency can reach more than 90%, and the current accuracy variation is within ±5%, which can reduce the color change of LEDs. MBI6901 has a full range of protection features, including over-voltage protection, overheating protection, open circuit and short circuit protection. In addition, the solution also has low electromagnetic interference characteristics and has passed the electromagnetic interference test EN55015 standard for lighting equipment.