UCC28251 Series

Advanced half-bridge/full-bridge PWM controller with pre-bias operation for offline applications

Catalog(3 parts)

Part	Output Configuration	Mounting Type	Function	Voltage - Supply (Vcc/Vdd)▲▼	Voltage - Supply (Vcc/Vdd)▲▼	Topology	Output Phases▲▼	Supplier Device Package	Control Features	Frequency - Switching▲▼	Frequency - Switching▲▼	Output Type	Number of Outputs▲▼	Package / Case	Operating Temperature▲▼	Operating Temperature▲▼	Package / Case▲▼	Package / Case▲▼
Texas Instruments UCC28251RGPR Full-Bridge, Half-Bridge, Push-Pull Regulator Positive Output Step-Up/Step-Down DC-DC Controller IC 20-QFN (4x4)	Positive	Surface Mount	Step-Up/Step-Down	4.699999809265137 V	17 V	Full-Bridge, Half-Bridge, Push-Pull	1 ul	20-QFN (4x4)	Current Limit, Enable, Frequency Control, Ramp, Soft Start	42000 Hz	945000 Hz	PWM Signal	2 ul	20-VFQFN Exposed Pad	125 °C	-40 °C
Texas Instruments UCC28251PWR Full-Bridge, Half-Bridge, Push-Pull Regulator Positive Output Step-Up/Step-Down DC-DC Controller IC 20-TSSOP	Positive	Surface Mount	Step-Up/Step-Down	4.699999809265137 V	17 V	Full-Bridge, Half-Bridge, Push-Pull	1 ul	20-TSSOP	Current Limit, Enable, Frequency Control, Ramp, Soft Start	42000 Hz	945000 Hz	PWM Signal	2 ul	20-TSSOP	125 °C	-40 °C	0.004394200164824724 m	0.004399999976158142 m
Texas Instruments UCC28251RGPT Full-Bridge, Half-Bridge, Push-Pull Regulator Positive Output Step-Up/Step-Down DC-DC Controller IC 20-QFN (4x4)	Positive	Surface Mount	Step-Up/Step-Down	4.699999809265137 V	17 V	Full-Bridge, Half-Bridge, Push-Pull	1 ul	20-QFN (4x4)	Current Limit, Enable, Frequency Control, Ramp, Soft Start	42000 Hz	945000 Hz	PWM Signal	2 ul	20-VFQFN Exposed Pad	125 °C	-40 °C

Key Features

• Prebiased StartupSynchronous Rectifier Control Outputs withProgrammable Delays (Including Zero DelaySupport)Voltage Mode Control with Input VoltageFeed-Forward or Current Mode ControlPrimary or Secondary-Side Control3.3-V, 1.5% Accurate Reference OutputLower Minimum Operating Frequency1% Accurate Cycle-by-Cycle Over CurrentProtection with Matched Duty Cycle OutputsProgrammable Soft-Start and Hiccup RestartTimerThermally Enhanced 4-mm × 4-mm VQFN-20Package and 20-pin TSSOP PackagePrebiased StartupSynchronous Rectifier Control Outputs withProgrammable Delays (Including Zero DelaySupport)Voltage Mode Control with Input VoltageFeed-Forward or Current Mode ControlPrimary or Secondary-Side Control3.3-V, 1.5% Accurate Reference OutputLower Minimum Operating Frequency1% Accurate Cycle-by-Cycle Over CurrentProtection with Matched Duty Cycle OutputsProgrammable Soft-Start and Hiccup RestartTimerThermally Enhanced 4-mm × 4-mm VQFN-20Package and 20-pin TSSOP Package

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. 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.