SLUSA16D March 2010 – November 2016 UCC28950
PRODUCTION DATA.
- 1 Features
- 2 Applications
- 3 Description
- 4 Revision History
- 5 Pin Configuration and Functions
- 6 Specifications
-
7 Detailed Description
- 7.1 Overview
- 7.2 Functional Block Diagram
- 7.3
Feature Description
- 7.3.1 Start-Up Protection Logic
- 7.3.2 Voltage Reference (VREF)
- 7.3.3 Error Amplifier (EA+, EA-, COMP)
- 7.3.4 Soft Start and Enable (SS/EN)
- 7.3.5 Light-Load Power Saving Features
- 7.3.6 Adaptive Delay, (Delay between OUTA and OUTB, OUTC and OUTD (DELAB, DELCD, ADEL))
- 7.3.7 Adaptive Delay (Delay between OUTA and OUTF, OUTB and OUTE (DELEF, ADELEF))
- 7.3.8 Minimum Pulse (TMIN)
- 7.3.9 Burst Mode
- 7.3.10 Switching Frequency Setting
- 7.3.11 Slope Compensation (RSUM)
- 7.3.12 Dynamic SR ON/OFF Control (DCM Mode)
- 7.3.13 Current Sensing (CS)
- 7.3.14 Cycle-by-Cycle Current Limit Current Protection and Hiccup Mode
- 7.3.15 Synchronization (SYNC)
- 7.3.16 Outputs (OUTA, OUTB, OUTC, OUTD, OUTE, OUTF)
- 7.3.17 Supply Voltage (VDD)
- 7.3.18 Ground (GND)
- 7.4 Device Functional Modes
-
8 Application and Implementation
- 8.1 Application Information
- 8.2
Typical Application
- 8.2.1 Design Requirements
- 8.2.2
Detailed Design Procedure
- 8.2.2.1 Power Loss Budget
- 8.2.2.2 Preliminary Transformer Calculations (T1)
- 8.2.2.3 QA, QB, QC, QD FET Selection
- 8.2.2.4 Selecting LS
- 8.2.2.5 Selecting Diodes DB and DC
- 8.2.2.6 Output Inductor Selection (LOUT)
- 8.2.2.7 Output Capacitance (COUT)
- 8.2.2.8 Select FETs QE and QF
- 8.2.2.9 Input Capacitance (CIN)
- 8.2.2.10 Current Sense Network (CT, RCS, R7, DA)
- 8.2.3 Application Curves
- 9 Power Supply Recommendations
- 10Layout
- 11Device and Documentation Support
- 12Mechanical, Packaging, and Orderable Information
1 Features
- Enhanced Wide Range Resonant Zero Voltage Switching (ZVS) Capability
- Direct Synchronous Rectifier (SR) Control
- Light-Load Efficiency Management Including
- Burst Mode Operation
- Discontinuous Conduction Mode (DCM), Dynamic SR On and Off Control with Programmable Threshold
- Programmable Adaptive Delay
- Average or Peak Current Mode Control With Programmable Slope Compensation and Voltage Mode Control
- Naturally Handles Pre-Biased Start Up With DCM Mode
- Closed Loop Soft Start and Enable Function
- Programmable Switching Frequency up to 1 MHz with Bi-Directional Synchronization
- (±3%) Cycle-by-Cycle Current Limit Protection With Hiccup Mode Support
- 150-µA Start-Up Current
- VDD Undervoltage Lockout
- Wide Temperature Range –40°C to +125°C
2 Applications
3 Description
The UCC28950 enhanced phase-shifted controller builds upon Texas Instrument’s industry standard UCx895 phase-shifted controller family with enhancements that offer best in class efficiency in today’s high performance power systems. The UCC28950 implements advanced control of the full-bridge along with active control of the synchronous rectifier output stage.
The primary-side signals allow programmable delays to ensure ZVS operation over wide-load current and input voltage range, while the load current naturally tunes the secondary-side synchronous rectifiers switching delays, maximizing overall system efficiency.
The UCC28950 also offers multiple light-load management features including burst mode and dynamic SR on/off control when transitioning in and out of Discontinuous Current Mode (DCM) operation, ensuring ZVS operation is extended down to much lighter loads.
In addition, the UCC28950 includes support for current or voltage mode control. Programmable switching frequency up to 1 MHz and a wide set of protection features including cycle-by-cycle current limit, UVLO and thermal shutdown. A 90-degree phase-shifted interleaved synchronized operation can be easily arranged between two converters.
The UCC28950 is available in TSSOP-24 package.
Device Information(1)
| PART NUMBER | PACKAGE | BODY SIZE (NOM) |
|---|---|---|
| UCC28950 | TSSOP (24) | 7.80 mm x 4.40 mm |
- For all available packages, see the orderable addendum at the end of the datasheet.
UCC28950 Typical Application
