ISL6551IREC Datasheet, PDF (1/23 Pages) Intersil Corporation – ZVS Full Bridge PWM Controller

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Data Sheet
ISL6551IREC
September 2, 2008
FN6762.0
ZVS Full Bridge PWM Controller
The ISL6551IREC is a zero voltage switching (ZVS) full
bridge PWM controller designed for isolated power systems.
This part implements a unique control algorithm for fixed
frequency ZVS current mode control, yielding high efficiency
with low EMI. The two lower drivers are PWM-controlled on
the trailing edge and employ resonant delay while the two
upper drivers are driven at a fixed 50% duty cycle.
This IC integrates many features in a 28 lead 6mmx6mm²
QFN package to yield a complete and sophisticated power
supply solution. Control features include programmable soft-
start for controlled start-up, programmable resonant delay
for zero voltage switching, programmable leading edge
blanking to prevent false triggering of the PWM comparator
due to the leading edge spike of the current ramp, adjustable
ramp for slope compensation, drive signals for implementing
synchronous rectification in high output current, ultra high
efficiency applications, and current share support for
paralleling up to 10 units, which helps achieve higher
reliability and availability as well as better thermal
management. Protective features include adjustable cycle-
by-cycle peak current limiting for overcurrent protection, fast
short-circuit protection (in hiccup mode), a latching shutdown
input to turn off the IC completely on output overvoltage
conditions or other extreme and undesirable faults, a non-
latching enable input to accept an enable command when
monitoring the input voltage and thermal condition of a
converter, and VDD undervoltage lockout with hysteresis.
Additionally, the ISL6551IREC includes high current high-
side and low-side totem-pole drivers to avoid additional
external drivers for moderate gate capacitance (up to 1.6nF
at 1MHz) applications, an uncommitted high bandwidth
(10MHz) error amplifier for feedback loop compensation, a
precision bandgap reference with ±1.5% or ±1% tolerance
over recommended operating conditions, and a ±5% “in
regulation” monitor.
In addition to the ISL6551IREC, other external elements
such as transformers, pulse transformers, capacitors,
inductors and Schottky or synchronous rectifiers are
required for a complete power supply solution. A detailed
200W telecom power supply reference design using the
ISL6551IREC with companion Intersil ICs, Supervisor and
Monitor ISL6550 and Half-bridge Driver HIP2100, is
presented in Application Note AN1002.
In addition, the ISL6551IREC can also be designed in push-
pull converters using all of the features except the two upper
drivers and adjustable resonant delay features.
Features
• Full Traceability Through Assembly and Test by
Date/Trace Code Assignment
• Enhanced Process Change Notification per MIL-PRF-38535
• Enhanced Obsolescence Management
• High Speed PWM (up to 1MHz) for ZVS Full Bridge
Control
• Current Mode Control Compatible
• High Current High-Side and Low-Side Totem-Pole Drivers
• Adjustable Resonant Delay for ZVS
• 10MHz Error Amplifier Bandwidth
• Programmable Soft-Start
• Precision Bandgap Reference
• Latching Shutdown Input
• Non-latching Enable Input
• Adjustable Leading Edge Blanking
• Adjustable Dead Time Control
• Adjustable Ramp for Slope Compensation
• Fast Short-Circuit Protection (Hiccup Mode)
• Adjustable Cycle-by-Cycle Peak Current Limiting
• Drive Signals to Implement Synchronous Rectification
• VDD Undervoltage Lockout
• Current Share Support
• ±5% “In Regulation” Indication
• QFN Package:
- Compliant to JEDEC PUB95 MO-220 QFN - Quad Flat
No Leads - Package Outline
- Near Chip Scale Package Footprint, which Improves
PCB Efficiency and has a Thinner Profile
Applications
• Full-Bridge and Push-Pull Converters
• Power Supplies for Off-line and Telecom/Datacom
• Power Supplies for High End Microprocessors and
Servers
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CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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