Different applications determine different driving modes of LED

Linear regulator to convert voltage power will face the problem, is the problem of the noise of the switch mode, LED drive the choice of conversion depends on what kind of application. - Bill Rypka Rypka Muzahid Maxim HB LED driver product marketing manager, Bill

What conversion mode

The problem of power consumption is reduced by converting the voltage to a linear regulator, which is more suitable for use in a switching circuit that eliminates noise (such as car audio) and therefore cannot be switched. The switching mode is characterized by very high conversion efficiency, but it also has the problem of noise, so choose what kind of conversion depends on what kind of application.

Usually, the charge pump drive efficiency varies with the input voltage, the voltage applied in a large range, the efficiency is low; and the application in the voltage range is relatively small, only when the voltage between the input and output are integer multiples of the relationship, it can achieve the maximum efficiency, but this in the actual battery powered applications is difficult to achieve. In contrast, the conversion efficiency of the inductor is less affected by the voltage interference, and the application limit is less than that of the charge pump. How to evaluate performance

Objectively speaking, the evaluation of the performance of the HB LED driver IC according to different applications, can not be generalized. For example, the application of decorative lamps in the RGB color change control requirements, this performance has become the main indicator, and in monochrome applications do not require this. And as the small space application requirements is heat capacity; automotive lighting alternative performance applications requires smoothing circuit combined with original system and high reliability requirements; in NB, display applications, the string LED balanced brightness control requirements driven IC have precise control on the current of each branch. Such as, the control precision of Maxim products can reach 3%; driving circuit of projector application requires high efficiency, rapid brightness adjustment ability and thermal protection ability; in alternative applications, the performance is more reflected in the entire program rather than a single drive on the IC. In general, the integration of the device, the number of control, response speed, fault diagnosis, heat resistance are the performance evaluation reference.

Usually, high integration aims to improve the performance, but under the high power, high set became meet large current will increase in chip area, increase the cost while facing the heat problem, so, how to balance the power and the degree of integration is the relationship between driver IC design task. Drive IC to improve the process to meet the cost of the chip at the same time, improve the package to solve the problem of heat dissipation.