Linear regulator to convert the voltage will face power problem, switch-mode noise is a problem, LED driver to choose which conversion depends on what kind of application.
What kind of conversion
Through the linear regulator to convert the voltage will face power problems, this approach is more suitable for the need to avoid the noise (such as car audio) and therefore can not use switch mode converter circuits. The switch means is characterized by very high conversion efficiency, but it also has noise problems, so what choice of conversion depends on the application.
Typically, the charge pump drive the efficiency of the input voltage changes, the voltage range of applications, their efficiency is relatively low; while relatively small in the voltage range of applications, only when the input and output voltage multiple relationship between the whole, it can achieve maximum efficiency, but in the practical application of battery-powered difficult to achieve. The other hand, the conversion efficiency is not affected by inductive voltage interfere with, the application limit is less than the charge pump, so the inductor current mode converter to use more.
How to evaluate the performance
Objective that the performance evaluation hb led driver ic point of view according to different applications, can not be generalized. Applications such as decorative lighting rgb color change of control requires high performance to be the main target of this, and in monochrome applications do not require this. Another example is the application of a small space requirements of the heat dissipation capacity; automotive lighting applications require both replace the original circuit system with smooth combination of performance also requires high reliability; in nb like displays, led multi-string balanced brightness control requirements for each one on the road driving ic have precise control of current, such as the maxim of the product control precision can reach 3%; projector applications require high efficiency driver circuit, the ability to quickly adjust the brightness and thermal protection capacity; in alternative applications, the performance is more reflected in the program rather than a single drive ic on. In general, device integration, control the quantity, response speed, fault diagnosis, evaluation of heat are all properties of reference.
Typically, the high level of integration aimed at improving performance, but at high power, highly integrated high current will increase to meet the chip area, but also in increasing the cost of the problems facing the heat, so, how to balance between power and integration The relationship is driven issues facing ic design. Driver ic chip technology to meet the cost of the improvement at the same time, improved cooling package to solve the problem.