Part # Application Note Lighting Control AN1757 datasheet

Part Manufacturer: ST Microelectronics

ST Microelectronics

Part Description: SWITCHING FROM THE L6561 TO THE L6562

Part Details:

AN1757 APPLICATION NOTE SWITCHING FROM THE L6561 TO THE L6562 by Luca Salati 1 INTRODUCTION Conceived on the same core of the L6561 and pin-to-pin compatible with it (see fig. 1), the L6562 is the newST s Transition Mode (TM) controller for high Power Factor Corrector stages: the replacement can be done withminimum or no modification of a stage designed with the L6561. As the building blocks of these two IC s are the same (fig. 1), one can design with the L6562 using the guidelinesgiven for L6561, in particular in the ST Application Note 966 ("L6561, enhanced transition mode power factorcorrector"). All the documentation produced for L6561 can be easily adapted to the L6562 ([1] [2] [3] [4]). The first paragraph of this Application Note is dedicated to explain the differences in terms of Electrical Charac-teristics between these two controllers: it will be clear that these modifications do not require component chang-ing when switching from L6561 to L6562.Besides providing good results in term of power factor, this new IC considerably reduces the Total HarmonicDistortion (THD) without need for external components: an innovative circuit improves the behavior of the sys-tem reducing the conduction dead-angle that occurs to the AC input current near the zero-crossings of the linevoltage (paragraph 3) making easier the compliancy with regulation. The increased gate driver capability (typically 600mA sourcing and 800mA sinking) makes the L6562 suitablefor a wide range of applications (with output power up to 300W).Based on that, L6562 can be fit the followingapplications: Lighting, IEC61000-3-2 compliant SMPS (TV, Desktop, PC, Monitors...), hi-end AC-DC adapter/charger, entry level server & web server. 2 L6562 VS. L6561: ELECTRICAL CHARACTERISTICS DIFFERENCES A series of tables will follow highlighting the differences between L6561 and L6562 in terms of Electrical Char-acteristics; at the end of each section, a short description explains the impact of these differences on the appli-cation and the consequent benefits. Figure 1. Block Diagram COMP MULT CS 2 3 4 1 INV - MULTIPLIER & 40K 2.5V + THD OPTIMIZER 5pF VOLTAGE OVER-VOLTAGE REGULATOR DETECTION VCC 15V 8 VCC 7V INTERNAL R 25V Q SUPPLY R1 S 7 + UVLO DRIVER GD VREF2 R2 - ZERO CURRENT - DETECTION 2.1V

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Application Note Lighting Control AN1757.pdf Datasheet