Datasheet LTC3722-1, LTC3722-2 (Analog Devices) - 10
| Fabricante | Analog Devices |
| Descripción | Synchronous Dual Mode Phase Modulated Full Bridge Controllers |
| Páginas / Página | 28 / 10 — TIMING DIAGRAM. OPERATION. Phase-Shift Full Bridge PWM |
| Revisión | C |
| Formato / tamaño de archivo | PDF / 607 Kb |
| Idioma del documento | Inglés |
TIMING DIAGRAM. OPERATION. Phase-Shift Full Bridge PWM
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LTC3722-1/LTC3722-2
TIMING DIAGRAM
PASSIVE LEG ACTIVE LEG DELAY DELAY OUTA OUTB OUTC OUTD COMP RAMP COMP COMP SYNC TURN OFF DELAY (PROGRAMMABLE) OUTE SYNC TURN OFF DELAY (PROGRAMMABLE) OUTF NOTE: SHADED AREAS CORRESPOND TO POWER DELIVERY PULSES. 372212 TD01
OPERATION Phase-Shift Full Bridge PWM
generally undesirable parasitic elements present within the Conventional full bridge switching power supply topologies power stage. The parasitic elements are utilized to drive are often employed for high power, isolated DC/DC and near lossless switching transitions for all of the external off-line converters. Although they require two additional power MOSFETs. switching elements, substantially greater power and higher LTC3722-1/LTC3722-2 phase-shift PWM controllers pro- efficiency can be attained for a given transformer size vide enhanced performance and simplify the design task compared to the more common single-ended forward and required for a ZVS phase-shifted full bridge converter. flyback converters. These improvements are realized since The primary attributes of the LTC3722-1/LTC3722-2 as the full bridge converter delivers power during both parts compared to currently available solutions include: of the switching cycle, reducing transformer core loss and lowering voltage and current stresses. The full bridge 1. Truly adaptive and accurate (DirectSenseTM technology) converter also provides inherent automatic transformer ZVS with programmable timeout. flux reset and balancing due to its bidirectional drive Benefit: higher efficiency, higher duty cycle capability, configuration. As a result, the maximum duty cycle range eliminates external trim. is extended, further improving efficiency. Soft-switching variations on the full bridge topology have been proposed 2. Fixed ZVS capability. to improve and extend its performance and application. Benefit: enables secondary-side control and simplifies These zero voltage switching (ZVS) techniques exploit the external circuit. Rev C 10 For more information www.analog.com Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Timing Diagram Operation Revision History Typical application Related Parts
TIMING DIAGRAM
PASSIVE LEG ACTIVE LEG DELAY DELAY OUTA OUTB OUTC OUTD COMP RAMP COMP COMP SYNC TURN OFF DELAY (PROGRAMMABLE) OUTE SYNC TURN OFF DELAY (PROGRAMMABLE) OUTF NOTE: SHADED AREAS CORRESPOND TO POWER DELIVERY PULSES. 372212 TD01
OPERATION Phase-Shift Full Bridge PWM
generally undesirable parasitic elements present within the Conventional full bridge switching power supply topologies power stage. The parasitic elements are utilized to drive are often employed for high power, isolated DC/DC and near lossless switching transitions for all of the external off-line converters. Although they require two additional power MOSFETs. switching elements, substantially greater power and higher LTC3722-1/LTC3722-2 phase-shift PWM controllers pro- efficiency can be attained for a given transformer size vide enhanced performance and simplify the design task compared to the more common single-ended forward and required for a ZVS phase-shifted full bridge converter. flyback converters. These improvements are realized since The primary attributes of the LTC3722-1/LTC3722-2 as the full bridge converter delivers power during both parts compared to currently available solutions include: of the switching cycle, reducing transformer core loss and lowering voltage and current stresses. The full bridge 1. Truly adaptive and accurate (DirectSenseTM technology) converter also provides inherent automatic transformer ZVS with programmable timeout. flux reset and balancing due to its bidirectional drive Benefit: higher efficiency, higher duty cycle capability, configuration. As a result, the maximum duty cycle range eliminates external trim. is extended, further improving efficiency. Soft-switching variations on the full bridge topology have been proposed 2. Fixed ZVS capability. to improve and extend its performance and application. Benefit: enables secondary-side control and simplifies These zero voltage switching (ZVS) techniques exploit the external circuit. Rev C 10 For more information www.analog.com Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Timing Diagram Operation Revision History Typical application Related Parts