UCC28251 Advanced PWM Controller with Pre-Bias Operation | TI.com

UCC28251 (ACTIVE)

Advanced PWM Controller with Pre-Bias Operation

 

Description

The UCC28251 PWM controller is designed for high power density applications that may have stringent prebiased startup requirements. The UCC28251’s integrated synchronous rectifier control outputs target high efficiency and high performance topologies such as half-bridge, full-bridge, interleaved forward, and push-pull. The UCC27210 half bridge drivers and UCC2752x MOSFET drivers used in conjunction with the UCC28251 provide a complete power converter solution.

The UCC28251 is a functional variant of the UCC28250 PWM Controller. While the same basic functionality of the UCC28250 is largely maintained, the UCC28251 is designed to enhance performance in both offline, 400-V input DC-to-DC applications and 48-V input full-bridge or half-bridge applications.

Externally programmable soft-start, used in conjunction with an internal pre-biased startup circuit, allows the controller to gradually reach a steady-state operating point under all output conditions. The UCC28251 can be configured for primary or secondary-side control and either voltage or current mode control can be implemented.

The oscillator operates at frequencies up to 1.8 MHz, and can be synchronized to an external clock. Input voltage feedforward, cycle-by-cycle current limit, and a programmable hiccup timer allow the system to stay within a safe operation range. Input voltage, output voltage and temperature protection can be implemented. Dead time between primary-side switch and secondary-side synchronous rectifiers can be independently programmed.

Features

  • Prebiased Startup
  • Synchronous Rectifier Control Outputs with
    Programmable Delays (Including Zero Delay
    Support)
  • Voltage Mode Control with Input Voltage
    Feed-Forward or Current Mode Control
  • Primary or Secondary-Side Control
  • 3.3-V, 1.5% Accurate Reference Output
  • Lower Minimum Operating Frequency
  • 1% Accurate Cycle-by-Cycle Over Current
    Protection with Matched Duty Cycle Outputs
  • Programmable Soft-Start and Hiccup Restart
    Timer
  • Thermally Enhanced 4-mm × 4-mm VQFN-20
    Package and 20-pin TSSOP Package

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Parametrics Compare all products in PWM controllers & resonant controllers

 
Topology
Control method
VCC (Min) (V)
VCC (Max) (V)
Frequency (Max) (kHz)
UVLO thresholds on/off (V)
Duty cycle (Max) (%)
Gate drive (Typ) (A)
Features
Rating
Operating temperature range (C)
Package Group
Package size: mm2:W x L (PKG)
UCC28251 LM5035B LM5035C LM5036 LM5039 UCC28250
Forward
Full-Bridge
Half-Bridge
Push-Pull    
Half-Bridge     Half-Bridge
Push-Pull    
Full-Bridge
Half-Bridge
Push-Pull    
Full-Bridge
Half-Bridge
Push-Pull    
Forward
Full-Bridge
Half-Bridge
Push-Pull    
Current
Feedforward
Voltage    
Feedforward
Voltage    
Feedforward
Voltage    
Feedforward
Voltage    
Voltage     Current
Voltage    
4.7     8     8       8     4.7    
17     15     15       15     17    
1000     2000     2000     2000     2000     1000    
4.3/4.1     Programmable/1.25V     Programmable/1.25V     Programmable/1.25V     Programmable/1.25V     4.3/4.1    
100     50     50     50     50     100    
0.2     2     2     2     2     0.2    
Current Limiting
Leading Edge Blanking
Multi-topology
Pre-Bias Start-Up
Programmable Slope Compensation
SR Logic
Soft Start
Synchronization Pin    
Current Limiting
HV Start-up
Multi-topology
Pre-Bias Start-Up
Synchronization Pin    
Current Limiting
HV Start-up
Multi-topology
Pre-Bias Start-Up
Synchronization Pin    
Current Limiting
Frequency Synchronization
HV Start-up
Input Line Monitor
Integrated Switch
Leading Edge Blanking
Multi-topology
Pre-Bias Start-Up
Soft Start
Synchronization Pin
Thermal Shutdown
Wide DC input    
Current Limiting
HV Start-up
Multi-topology
Synchronization Pin    
Current Limiting
HV Start-up
SR Logic    
Catalog     Catalog     Catalog     Catalog     Catalog     Catalog    
-40 to 125     -40 to 125     -40 to 125     -40 to 125     -40 to 125     -40 to 125    
QFN | 20
TSSOP | 20    
HTSSOP | 20
WQFN | 24    
HTSSOP | 20
WQFN | 24    
WQFN | 28     HTSSOP | 20
WQFN | 24    
QFN | 20
TSSOP | 20    
20QFN: 16 mm2: 4 x 4 (QFN | 20)
20TSSOP: 42 mm2: 6.4 x 6.5 (TSSOP | 20)    
20HTSSOP: 42 mm2: 6.4 x 6.5 (HTSSOP | 20)
24WQFN: 20 mm2: 4 x 5 (WQFN | 24)    
20HTSSOP: 42 mm2: 6.4 x 6.5 (HTSSOP | 20)
24WQFN: 20 mm2: 4 x 5 (WQFN | 24)    
28WQFN: 25 mm2: 5 x 5 (WQFN | 28)     20HTSSOP: 42 mm2: 6.4 x 6.5 (HTSSOP | 20)
24WQFN: 20 mm2: 4 x 5 (WQFN | 24)    
20QFN: 16 mm2: 4 x 4 (QFN | 20)
20TSSOP: 42 mm2: 6.4 x 6.5 (TSSOP | 20)