FAN7621_10 Datasheet, PDF (1/17 Pages) Fairchild Semiconductor – PFM Controller for Half-Bridge Resonant Converters

July 2010
FAN7621
PFM Controller for Half-Bridge Resonant Converters
Features
ƒ Variable Frequency Control with 50% Duty Cycle
for Half-bridge Resonant Converter Topology
ƒ High Efficiency through Zero Voltage Switching (ZVS)
ƒ Fixed Dead Time (350ns)
ƒ Up to 300kHz Operating Frequency
ƒ Pulse Skipping for Frequency Limit (Programmable)
at Light-Load Condition
ƒ Remote On/Off Control Using CON Pin
ƒ Protection Functions: Over-Voltage Protection
(OVP), Overload Protection (OLP), Over-Current
Protection (OCP), Abnormal Over-Current Protection
(AOCP), Internal Thermal Shutdown (TSD)
Applications
ƒ PDP and LCD TVs
ƒ Desktop PCs and Servers
ƒ Adapters
ƒ Telecom Power Supplies
ƒ Video Game Consoles
Description
The FAN7621 is a pulse frequency modulation controller
for high-efficiency half-bridge resonant converters.
Offering everything necessary to build a reliable and
robust resonant converter, the FAN7621 simplifies
designs and improves productivity, while improving
performance. The FAN7621 includes a high-side gate-
drive circuit, an accurate current controlled oscillator,
frequency limit circuit, soft-start, and built-in protection
functions. The high-side gate-drive circuit has a
common-mode noise cancellation capability, which
guarantees stable operation with excellent noise
immunity. Using the zero-voltage-switching (ZVS)
technique dramatically reduces the switching losses and
efficiency is significantly improved. The ZVS also
reduces the switching noise noticeably, which allows a
small-sized Electromagnetic Interference (EMI) filter.
The FAN7621 can be applied to various resonant
converter topologies; such as series resonant, parallel
resonant, and LLC resonant converters.
Related Resources
AN4151 — Half-bridge LLC Resonant Converter Design
using FSFR-series Fairchild Power Switch (FPS^TM)
Ordering Information
Part Number
Operating Junction
Temperature
FAN7621N
FAN7621SJ
FAN7621SJX
-40°C ~ 130°C
Package
Packaging Method
16-Lead, Dual Inline Package (DIP)
16-Lead, Small-Outline Package (SOP)
16-Lead, Small-Outline Package (SOP)
Tube
Tube
Tape & Reel
© 2009 Fairchild Semiconductor Corporation
FAN7621 • Rev. 1.0.3
www.fairchildsemi.com