Part # Application Notes Power Supply And Power Management EVAL6926D L6926 AN1882 datasheet

Part Manufacturer: ST Microelectronics

ST Microelectronics

Part Description: DESIGNING WITH L6926, HIGH EFFICIENCY MONOLITHIC SYNCHRONOUS STEP DOWN REGULATOR


Part Details:

AN1882 APPLICATION NOTE DESIGNING WITH L6926, HIGH EFFICIENCY MONOLITHIC SYNCHRONOUS STEP DOWN REGULATOR by Massimiliano Merisio and Milko Paolucci This application note details the main features and application advantages of this new synchro-nous step down regulator. After describing how the device works and the main features, a step-by-step design section is provided in order to help the selection of the external components andthe evaluation of the losses. The device performances are shown in terms of efficiency and ther-mal results. At the end, some application ideas are proposed. TABLE OF CONTENTS 1 INTRODUCTION ................................................................................................................................2 2 PINS FUNCTION ...............................................................................................................................3 3 BLOCK DIAGRAM .............................................................................................................................3 4 FUNCTIONAL DESCRIPTION ...........................................................................................................44.1 MODES OF OPERATION........................................................................................................4 4.1.1 Low Consumption Mode.....................................................................................................44.1.2 Low Noise Mode.................................................................................................................4 4.2 SYSTEM STABILITY ...............................................................................................................5 4.2.1 Current Loop Compensation ..............................................................................................54.2.2 Voltage Loop Compensation ..............................................................................................6 4.3 SHORT CIRCUIT PROTECTION ............................................................................................8 4.4 SYNCHRONIZATION ..............................................................................................................9 4.5 DROPOUT OPERATION .........................................................................................................9 4.6 PGOOD (Power Good Output)...............................................................................................10 4.7 ADJUSTABLE OUTPUT VOLTAGE ......................................................................................10 4.8 OVP (Over voltage Protection)............................................................................................... 10 4.9 HYSTERETIC THERMAL SHUTDOWN ................................................................................10 5 APPLICATION INFORMATIONS .....................................................................................................115.1 EXTERNAL COMPONENTS SELECTION ............................................................................11 5.1.1 Input Capacitor .................................................................................................................115.1.2 Output Capacitor ..............................................................................................................115.1.3 Inductor ............................................................................................................................125.1.4 Compensation network (R1C3) ........................................................................................12 5.2 LOSSES and EFFICIENCY ...................................................................................................13 5.2.1 Conduction Losses. ..........................................................................................................135.2.2 Switching Losses..............................................................................................................135.2.3 Gate Charge Losses ........................................................................................................13 5.3 THERMAL CONSIDERATIONS.............................................................................................14 5.3.1 APPLICATION BOARD ....................................................................................................15 5.4 EFFICIENCY RESULTS ........................................................................................................17 6 APPLICATION IDEAS ......................................................................................................................186.1 BUCK BOOST TOPOLOGY ..................................................................................................18 6.2 WHITE LED............................................................................................................................18 6.2.1 Driving White LEDs: Buck Topology ................................................................................186.2.2 Driving White LEDs: Boost Topology ...............................................................................196.2.3 Driving White LEDs: Buck_Boost Topology .....................................................................20 April 2004 1/21


Please click the following link to download the datasheet:

Application Notes Power Supply And Power Management EVAL6926D L6926 AN1882.pdf Datasheet