FAN7621S Datasheet, PDF (1/13 Pages) Fairchild Semiconductor – PFM Controller for Half-Bridge Resonant Converters

July 2010
FAN7621S
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 Auto-Restart Operation for All Protections with
an External LVCC
ƒ Protection Functions: Over-Voltage Protection
(OVP), 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 FAN7621S 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 FAN7621S
simplifies designs and improves productivity, while
improving performance. The FAN7621S 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
significantly improves efficiency. The ZVS also reduces
the switching noise noticeably, which allows a small-
sized Electromagnetic Interference (EMI) filter.
The FAN7621S 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
FAN7621SSJ
FAN7621SSJX
-40°C to +130°C
Package
16-Lead, Small Outline Package (SOP)
Packaging
Method
Tube
Tape & Reel
© 2009 Fairchild Semiconductor Corporation
FAN7621S • Rev. 1.0.1
www.fairchildsemi.com