Datasheet Linear Technology LT3781 — Ficha de datos

Fabricante	Linear Technology
Serie	LT3781

Bootstrap Start Dual Transistor Forward Synchronous Forward Controller

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PDF, 260 Kb, Idioma: en, Archivo subido: sept 19, 2017, Páginas: 20
Bootstrap Start Dual Transistor Synchronous Forward Controller

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Precios

Embalaje

	LT3781EG#PBF	LT3781EG#TRPBF	LT3781IG#PBF	LT3781IG#TRPBF
N	1	2	3	4
Package	SSOP-20 Dibujo del esquema del paquete	SSOP-20 Dibujo del esquema del paquete	SSOP-20 Dibujo del esquema del paquete	SSOP-20 Dibujo del esquema del paquete
Package Code	G	G	G	G
Package Index	05-08-1640 (G20)	05-08-1640 (G20)	05-08-1640 (G20)	05-08-1640 (G20)
Pin Count	20	20	20	20

Paramétricos

Parameters / Models	LT3781EG#PBF	LT3781EG#TRPBF	LT3781IG#PBF	LT3781IG#TRPBF
Demo Boards	DC448A,DC467A,DC479A,DC610A,DC617A	DC448A,DC467A,DC479A,DC610A,DC617A	DC448A,DC467A,DC479A,DC610A,DC617A	DC448A,DC467A,DC479A,DC610A,DC617A
Design Tools	LTspice Model	LTspice Model	LTspice Model	LTspice Model
Export Control	no	no	no	no
Features	External Synchronization	External Synchronization	External Synchronization	External Synchronization
Frequency, kHz	350	350	350	350
Frequency Sync Range	Up to 350kHz	Up to 350kHz	Up to 350kHz	Up to 350kHz
Integrated Inductor	no	no	no	no
Isupply, mA	17	17	17	17
Monolithic	no	no	no	no
Number of Outputs	1	1	1	1
Operating Temperature Range, °C	0 to 85	0 to 85	-40 to 85	-40 to 85
Output Current, A	20	20	20	20
Polyphase	no	no	no	no
Switch Current, A	20	20	20	20
Synchronous	yes	yes	yes	yes
Topology	Forward	Forward	Forward	Forward
Vin Max, V	72	72	72	72
Vin Min, V	8	8	8	8
Vout Max, V	72	72	72	72
Vout Maximum	VIN	VIN	VIN	VIN
Vout Min, V	1.25	1.25	1.25	1.25

Plan ecológico

	LT3781EG#PBF	LT3781EG#TRPBF	LT3781IG#PBF	LT3781IG#TRPBF
RoHS	Obediente	Obediente	Obediente	Obediente

Notas de Diseño

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Secondary Side Dual Output Controller Tightly Regulates Two Isolated Outputs &mdash DN1000
PDF, 90 Kb, Archivo publicado: dic 1, 2003
Extracto del documento
advertisement Secondary Side Dual Output Controller Tightly Regulates Two
Isolated Outputs вЂ“ Design Note 1000
Charlie Zhao and Wei Chen
Introduction
Many systems with dual output isolated power supplies
require tight regulation on both outputs. The LTВ®3804
makes it possible to satisfy this requirement in a space
saving and efficient circuit.
The LT3804 is a secondary side dual output controller. It
contains an error amplifier and an optocoupler driver to
regulate the first output. It also includes a complete PWM
controller and dual N-channel MOSFET drivers for the
second output. The power to the second output is transferred directly from the transformer secondary winding
without going through the first output stage, thus minimizing the size of the output inductor and capacitor of the
first output. Accurate output regulation for both outputs is
assuredвЂ”even if the power supplyвЂ™s outputs are far away
from the actual loadsвЂ”due to true differential remote
sensing.
Dual Output Isolated Power Supply
Figure 1 shows a dual output high efficiency isolated
DC/DC power supply with 36V to 72V input range and two
outputs of 3.3V/15A and 1.8V/15A. The basic power stage
topology is a 2-switch forward converter with synchronous rectification. The primary side is controlled by the …
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Multiple Output Isolated Power Supply Achieves High Efficiency with Secondary Side Synchronous Post Regulator &mdash DN299
PDF, 85 Kb, Archivo publicado: nov 1, 2002
Extracto del documento
Multiple Output Isolated Power Supply Achieves High Efficiency with Secondary Side Synchronous Post Regulator
Design Note 299
Charlie Zhao and Wei Chen
Introduction
The newly released LTВ®3710, a secondary side synchronous post regulator controller, provides tight regulation
for all outputs of multiple output isolated power supplies. Solutions that use the LT3710 are efп¬Ѓcient, use
minimal space and provide fast transient response. controller uses the LT3781; a current mode 2-switch
forward controller with built-in MOSFET drivers. On
the secondary side a synchronous rectiп¬Ѓer controller, the LTC1698, provides the voltage feedback for
the main 3.3V output as well as the gate drive for the
synchronous MOSFETs. The LT3710 circuit precisely
regulates the 2.5V output. Total load and line regulation for the 2.5V output is better than 0.2%. From a
48V input, the overall efп¬Ѓciency is about 87% with full
load on both outputs. The LT3710 is a voltage mode controller with leading
edge modulation, programmable current limit and
dual MOSFET drivers. It generates a tightly regulated
second output directly from the transformer secondary
winding, thus minimizing the size of the output inductor
and capacitor of the main output stage. The use of synchronous MOSFETs signiп¬Ѓcantly improves efп¬Ѓciency,
making it suitable for low output voltage applications. Conclusion
The LT3710 is a high efп¬Ѓciency secondary side synchronous post regulator controller that is designed
to generate a tightly regulated secondary output for
multiple output isolated power supplies. It can be used …

Linea modelo

Serie: LT3781 (4)

LT3781EG#PBF LT3781EG#TRPBF LT3781IG#PBF LT3781IG#TRPBF

Clasificación del fabricante

Power Management > Switching Regulator > Flyback, Forward and Isolated Controllers