UCC28950EVM-442(#1): 12V @ 50A, 390VDC in

Summary

This 600-W EVM was designed to demonstrate how the UCC28950 control device could be used in high-efficiency applications by achieving ZVS from 50% to 100% load. To achieve this high efficiency the UCC28950 was designed to drive synchronous rectifiers on the secondary side of the full bridge converter. The UCC28950 also incorporates a burst mode and DCM function to improve no-load efficiency. Please see UCC28950 data sheet for details (TI Literature Number SLUSA16).

The DCM (Discontinues Current Mode) comparator was designed to turn off the synchronous rectifiers before the output current reaches critical conduction at lighter loads (under 20%). This does two things. First it removes the energy that is required to drive the FETs at lighter loads. Second the DCM feature prevents the output inductor from developing a negative current that can damage the output synchronous rectifiers under no load/transient conditions.

Specifications

Manufacturer	Texas Instruments
Category	AC/DC and DC/DC Conversion
Sub-Category	DC/DC SMPS - Single Output
Eval Board Part Number	296-28920-ND
Eval Board Supplier	Texas Instruments
Eval Board	Normally In Stock
Topology	Step Down
Outputs and Type	1 Isolated
Voltage Out: Factory Set	12 V
Current Out	50 A
Voltage In	370 ~ 410 VDC
Efficiency @ Conditions	>95%, 390V in, 12V @ 15 ~ 37 A >94%, 390V in, 12V @ 10 ~ 50 A
Voltage Out Range	- Not Given
Features	Light Load Mode
Switching Frequency	- Not Given
Standby Current [Typical]
Quiescent Current [Typical]
Component Count + Extras	135 + 6
Internal Switch	No
Design Author	Texas Instruments
Application / Target Market	Servers Telecom
Standby Current [Maximum]
Quiescent Current [Maximum]
Main I.C. Base Part	UCC28950
Date Created By Author	2010-05
Date Added To Library	2012-11