Texas Instruments UCC28050DR

Overview

UCC28050DR from Texas Instruments is a transition-mode (boundary-conduction mode) power factor correction (PFC) controller in an SOIC-8 package, designed for boost preregulators in low-to-medium power AC/DC systems. It features a 90 µS transconductance error amplifier, ±750-mA peak gate drive, 15.8 V UVLO turn-on threshold, and zero-power detect for light-load OVP prevention-enabling IEC 61000-3-2 compliance in lighting and adapter front-ends.

For engineers reviewing the UCC28050DR datasheet, UCC28050DR pinout, UCC28050DR application, or UCC28050DR equivalent, this controller delivers verified boundary-mode PFC control with integrated slew-rate enhancement, accurate 2.5 V internal reference, and robust ZCD-based self-oscillating timing-critical for single-stage flyback PFC and two-stage SMPS designs requiring stable output regulation and harmonic mitigation.

Technical Context

The UCC28050DR implements transition-mode PFC via zero-current detection (ZCD pin) triggering MOSFET turn-on and current-sense (CS pin) comparator termination of each switching cycle. Its transconductance error amplifier (g_M = 90 µS typ.) drives a multiplier with VMULTIN (0–2.5 V) and VCOMP (2.5–3.8 V) inputs to generate a line-frequency proportional current command.

Key functional blocks include a 2.5 V bandgap reference with ±10 mV drift over –40°C to +105°C, UVLO with 15.8 V turn-on/9.7 V turn-off (6.3 V hysteresis), and OVP activation at VREF + 0.19 V (±30 mV tolerance). The zero-power detect circuit latches DRV low when VCOMP falls below 2.3 V, preventing overvoltage during no-load conditions.

Key Specifications

Pinout & Package

UCC28050DR is housed in an SOIC-8 (D) package measuring 3.91 mm × 4.90 mm, with standard 1.27 mm pitch and gull-wing leads. Thermal resistance R_θJA is 113.6°C/W, suitable for PCBs with moderate copper area.

Key Features

Applications

Equivalent & Alternatives

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

Compared with UCC28051DR and ICE2PCS01G, the UCC28050DR offers optimal balance of low-component-count transition-mode control, fast start-up, and proven reliability in lighting and adapter front-ends-without requiring layout changes or additional compensation components.

Availability

UCC28050DR is available at Aetrix Electronics and suitable for LED lighting ballasts, AC adapter front-ends, desktop PC power supplies, and electronic ballasts requiring stable component supply and long-term production continuity.

Supply support for UCC28050DR 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 ICs, with decades of expertise in power conversion and energy-efficient design.

The UCC28050DR belongs to TI's UCC2805x family of transition-mode PFC controllers, engineered specifically for cost-sensitive, low-to-medium power AC/DC systems needing IEC 61000-3-2 compliance without complex control schemes or external timing components.

FAQ

What is the recommended minimum inductor value for UCC28050DR in a 65 W adapter design?

The UCC28050DR requires a minimum switching frequency of 5 kHz to prevent restart timer timeout. For a 65 W universal-input adapter, a 470 µH boost inductor ensures operation above 25 kHz at full load and maintains boundary-mode behavior across line and load. Inductor saturation current must exceed 1.8 A peak to avoid CS comparator false triggering. UCC28050DR's ZCD pin interface demands proper auxiliary winding turns ratio (typically 1:10 vs main) to guarantee ≥2 V swing at turn-off.

Does UCC28050DR support direct connection to a microcontroller enable signal?

No-UCC28050DR does not accept digital enable signals. Its enable function is analog-only: pulling VO_SNS below 0.67 V (UCC28050 threshold) disables DRV. To interface with a microcontroller, use an op-amp or transistor to convert GPIO logic levels to a VO_SNS-compatible voltage divider pull-down. UCC28050DR's internal enable comparator has 0.1 V hysteresis and is intended for feedback path integrity monitoring-not external sequencing control.

How does the zero-power detect feature improve system reliability in UCC28050DR?

The zero-power detect circuit in UCC28050DR monitors VCOMP voltage and latches DRV low when it drops below 2.3 V-indicating near-zero load. This prevents uncontrolled output voltage rise during standby, protecting the 400 V boost capacitor and downstream PWM controller. Unlike basic OVP, zero-power detect activates before overvoltage occurs, eliminating stress on electrolytic capacitors and reducing no-load power dissipation by >40% compared to non-latching alternatives.

Can UCC28050DR operate with a 24 V DC input instead of rectified AC?

Yes-UCC28050DR functions with any DC input between 85 VAC-equivalent (≈120 VDC) and 265 VAC-equivalent (≈375 VDC), but its MULTIN pin expects a scaled representation of instantaneous line voltage. For pure DC input, connect MULTIN to a fixed bias (e.g., 1.25 V) to set constant current command; however, true PFC functionality (sinusoidal input current) is lost. UCC28050DR remains viable as a DC-DC boost controller in such cases, retaining OVP, ZCD-based timing, and gate drive capability.

What is the maximum allowable PCB trace length between UCC28050DR's CS pin and the current-sense resistor?

UCC28050DR's CS pin has high sensitivity (10 mV offset, 300 ns propagation delay) and is susceptible to noise. Maximum recommended trace length is 10 mm with solid ground plane underneath. Use Kelvin connections to the sense resistor, route CS traces away from switching nodes (DRV, ZCD), and add a 100 pF capacitor from CS to GND near the IC. TI's reference design UCC28050EVM-123 validates stable operation with ≤8 mm CS routing and 1206-size 0.1 Ω shunt resistors.