Texas Instruments UCC28051DRG4

Overview

UCC28051DRG4 from Texas Instruments is a transition-mode (boundary-conduction mode) power factor correction (PFC) controller for low-to-medium power AC-DC converters, featuring 12.5 V UVLO turn-on threshold, ±750-mA peak gate drive, and 2.5 V internal reference voltage. It operates in boost preregulator topology with zero-current detection (ZCD), supports IEC 61000-3-2 compliance, and targets applications where downstream PWM control coordination is required.

For engineers reviewing the UCC28051DRG4 datasheet, UCC28051DRG4 pinout, UCC28051DRG4 application, or UCC28051DRG4 equivalent, this device is selected for its light-load zero-power detect OVP prevention, slew-rate-enhanced transconductance error amplifier, and narrow UVLO hysteresis enabling synchronized start-up with secondary-stage controllers in two-stage SMPS designs.

Technical Context

The UCC28051DRG4 implements variable-frequency transition-mode control using an internal zero-current detector (ZCD) to trigger MOSFET turn-on at inductor current zero-crossing, while current-sense (CS) comparator termination governs turn-off. Its transconductance error amplifier (g_M = 90 µS typ.) drives a two-input analog multiplier that generates line-current shaping command proportional to rectified input voltage (MULTIN) and error voltage (COMP).

UVLO is configured with 12.5 V turn-on and 9.7 V turn-off thresholds (2.8 V hysteresis), enabling controlled activation by downstream PWM controllers. Overvoltage protection activates at V_{O_SNS} ≥ V_REF + 0.18 V (≈2.68 V), with 180 mV hysteresis, and zero-power detection engages when COMP falls below 2.3 V-preventing output overvoltage during no-load conditions.

Key Specifications

Pinout & Package

UCC28051DRG4 is housed in an 8-pin SOIC (D) package measuring 3.91 mm × 4.90 mm, with GND referenced thermal pad not electrically connected. Pin functions are validated per TI SLUS515G Rev G.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar transition-mode PFC controller applications.

Compared with UCC28050DRG4, UCC28051DRG4 trades faster start-up for precise system-level sequencing; versus ICE2PCS01G, it delivers superior light-load efficiency and simpler magnetics but requires external ZCD winding and lacks HV startup-making it optimal for cost-sensitive, two-stage, medium-power CRM applications.

Availability

UCC28051DRG4 is available at Aetrix Electronics and suitable for AC adapter front-ends, two-stage desktop SMPS, and industrial motor drive input stages requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for UCC28051DRG4 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and power management technologies, with decades of expertise in power conversion ICs.

The UCC28051DRG4 belongs to TI's transition-mode PFC controller product line, designed specifically for cost-effective, high-efficiency, IEC 61000-3-2-compliant AC-DC front-ends in two-stage power supplies and compact adapters.

FAQ

What is the UVLO behavior of the UCC28051DRG4, and how does it differ from UCC28050DRG4?

The UCC28051DRG4 features a 12.5 V turn-on threshold and 9.7 V turn-off threshold, yielding a narrow 2.8 V hysteresis-designed to allow precise activation by a downstream PWM controller's VCC rail. In contrast, the UCC28050DRG4 uses a 15.8 V turn-on and 9.7 V turn-off (6.3 V hysteresis) for standalone, fast-start applications. This difference makes UCC28051DRG4 ideal for coordinated two-stage power systems where timing control is critical.

How does the zero-power detect function prevent overvoltage in the UCC28051DRG4?

The UCC28051DRG4 monitors the COMP pin voltage and activates zero-power detect when it falls below 2.3 V-causing the gate driver (DRV) to shut down. This occurs under light/no-load conditions when the error amplifier output collapses, preventing uncontrolled output voltage rise. Unlike standard OVP, this mechanism acts proactively before overvoltage develops, eliminating need for external brownout circuitry in AC adapters using UCC28051DRG4.

Can the UCC28051DRG4 be used in continuous conduction mode (CCM) PFC designs?

No-the UCC28051DRG4 is architecturally optimized for transition-mode (boundary-conduction) operation only. It relies on zero-current detection (ZCD pin) to trigger switching and lacks CCM-specific features like ramp compensation or fixed-frequency oscillator control. Attempting CCM use would result in unstable operation and failure to meet IEC 61000-3-2 requirements. For CCM, TI recommends UCC28070 or similar dedicated CCM controllers instead of UCC28051DRG4.

What is the role of the 75 mV offset in the MULTIN path of the UCC28051DRG4?

The 75 mV offset applied to the MULTIN signal inside the UCC28051DRG4 compensates for diode conduction nonlinearity near AC zero-crossings, reducing current waveform distortion and improving total harmonic distortion (THD) performance. This internal offset eliminates the need for external calibration or trimming networks in the line-voltage sensing divider, simplifying layout and enhancing consistency across production units of UCC28051DRG4-based designs.

Does the UCC28051DRG4 require external components for ZCD signal conditioning?

The UCC28051DRG4 integrates active clamping on the ZCD pin (–0.3 V to +6 V range) and filters switching noise internally, so no external diodes or RC snubbers are required for basic operation. However, an external series resistor between the auxiliary winding and ZCD pin is necessary to limit peak ZCD current to <10 mA, as specified in the datasheet. No additional filtering is needed unless extreme EMI environments demand further noise suppression beyond what UCC28051DRG4 provides.