Different application decision LED display driver, within certain display area, at the same time, light up the number of rows and the whole area in proportion to the number of lines, called scanning way; Indoor double color for 1/16 scanning, commonly indoor full-color generally is 1/8 scanning, outdoor single color is usually 1/4 scan, outdoor full-color is generally static scan.
Currently on the market of LED display driver means has two kinds of static scan and dynamic scan, static scan is divided into static compaction pixels and static virtual, dynamic scanning is also divided into dynamic realities and dynamic virtual; MBI5026 driving device generally HC595 are needed in China, Taiwan, Japan's Toshiba TB62726, generally has a 1/2, 1/4, 1/8, 1/16.
However, linear regulators to convert the voltage power consumption problems, moreover, its switch mode has the problem of noise, the led driver choose what kind of transformation way?

What kind of transformation way

Through linear regulators to convert the voltage power consumption problems, this way is fit for the demands for

 avoiding noise (such as car audio) and thus cannot use the switch mode conversion circuit. And the characteristics of the switch mode conversion efficiency is very high, but it also has the problem of noise, so choose what kind of transformation way depends on what kind of application.

In general, the efficiency of charge pump drive way changes with the change of the input voltage, in the application of large range of voltage change, its efficiency is low; And in the application of voltage variation range is small, only when the input and output voltage is a multiple relationship between, it's to achieve maximum efficiency, but it is difficult to achieve in the practical application of battery power. In contrast, the inductance of the conversion efficiency is not affected by voltage disturbance, application limits is less than the charge pump, so the conversion circuit adopts the inductive method.
The characteristics of the LED display driver
According to the rules and characteristics of the LED drive power supply electricity requirement, want to consider when choosing and design LED drive power supply to the following points: (1) high reliability especially like LED street lamp driver power supply, in a high altitude, maintenance is not convenient, the cost of maintenance is big also, (2) high efficiency LED to energy saving products, thus driving the power efficiency is higher. For the structure of the power supply installed in the lamps and lanterns, especially, mainly because the LED heat dissipation is very important. The power efficiency is high, its power consumption is small, in the lamps and lanterns of calorific value is small, also lower the temperature of lamps and lanterns. (3) high power factor power factor is the requirement of load. Generally below 70 watts of electrical appliances, there is no mandatory indicators. Though the power of a single use lower electric power factor, the impact is not big, but at night you light a lamp and its load is too concentrated, serious pollution will be produced. (4) drive way Now there are two general types: (1) how much a constant voltage source for a constant current source, each constant-current source separate for each LED power supply. This way, flexible combination, LED failure all the way, don't affect the work of other leds, but the cost would be slightly higher. (2) directly out of the power supply, LED series or parallel operation. It has the advantage of low cost, but poor flexibility, but also solve a LED failure, does not affect other LED running problem. These two forms, for a period of time. Multi-channel constant current output power supply way, in terms of cost and performance will be better. May be the mainstream direction in the future. (5) the ability of anti surge surge protection LED is relatively poor, especially the reverse voltage resistance. Strengthening the protection is also very important. LED drive power supply requires inhibit the invasion of the surge, protect the LED is not damaged. (6) protection function Power supply in addition to conventional protection function, it is better to add the LED temperature in the constant current output feedback, generic LED temperature too high. (7) protection type lamps and lanterns is installed outside, power supply structure to waterproof, moistureproof, shell to fast. (8) the life of the drive power supply and LED the life of the adapter. (9) must be in accordance with safety regulations and the requirements of electromagnetic compatibility

How to evaluate the performance

Objective, evaluation of hb led driver IC performance according to the different application, cannot treat as the same. Such as decorative lighting applications in the control of the RGB color change demand is high, the performance becomes the main index, and in monochrome application does not require this. And as the application of narrow space requirement is heat dispersion ability; Automotive lighting alternative applications requires both the smooth with the original circuit system performance at the same time also require high reliability; In nb display applications, such as the series of led brightness more balanced control driver IC has precise control on every one of the current on the road, the product accuracy can reach 3%; Projector applications require high efficient drive circuit, the ability to rapidly adjust brightness and thermal protection; In alternative applications, the performance is more reflected in the whole solution rather than a single driver IC. In general, integration of components, control the quantity, response speed, fault diagnosis, heat-resistant and so on all is the performance evaluation reference.

Usually, high integration aims to improve performance, but at high power, high integration in order to satisfy the large current will increase the chip area, while increasing costs also faces the problem of heat dissipation, so, how to balance the relationship between the power and integration issue is the driver IC design. Driver IC to the chip process improvement to meet the cost at the same time, to improve the packaging solution to the problem of heat dissipation.

This article key words: BVSION HONGKONG CO.,LIMITED, BVSION, BVS, LCD screen, LCD, LCD driver, INNOLUX LCD

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