Texas Instruments UCC28050P

Overview

UCC28050 from Texas Instruments is a transition-mode (boundary-conduction mode) power factor correction (PFC) controller for low-to-medium power boost preregulators, featuring 2.5 V internal reference voltage, ±750-mA peak gate drive current, 15.8 V UVLO turn-on threshold, and zero-power detect for light-load OVP prevention - used in electronic ballasts and single-stage PFC flyback converters.

For engineers reviewing the UCC28050 datasheet, UCC28050 pinout, UCC28050 application, or UCC28050 equivalent, this device supports IEC 61000-3-2 harmonic compliance, delivers fast transient response via slew-rate-enhanced transconductance amplifier, and enables compact design with low start-up current (75 µA) and SOIC-8 packaging.

Technical Context

The UCC28050 implements transition-mode control using zero-current detection (ZCD) to trigger switch turn-on and current-sense (CS) comparator to terminate conduction - eliminating need for external frequency-setting components. Its transconductance error amplifier (g_M = 90 µS typ.) drives a two-input analog multiplier that generates line-current command proportional to rectified AC input (via MULTIN) and output error (via COMP).

Integrated protection includes overvoltage shutdown (OVP threshold = V_REF + 0.19 V), open-feedback disable (ENABLE threshold = 0.67 V), and zero-power latch (activated when COMP < 2.3 V). The 750-mA totem-pole DRV output directly drives external MOSFETs without external buffers, supporting fast rise/fall times (25 ns / 10 ns typical with 1 nF load).

Key Specifications

Pinout & Package

UCC28050 is housed in an 8-pin SOIC package (3.91 mm × 4.90 mm body size) with standard JEDEC MS-012AC footprint and Pb-free finish.

Key Features

Applications

Equivalent & Alternatives

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

Compared with UCC28051, the UCC28050 offers faster start-up and stronger transient response due to higher UVLO and g_M source current; compared with ICE2PCS01, it uses simpler transition-mode control with lower EMI and no external sense resistor, but lacks integrated power switch and fixed-frequency operation.

Availability

UCC28050 is available at Aetrix Electronics and suitable for electronic ballasts, desktop PC power supplies, AC adapter front-ends, and single-stage PFC flyback converters requiring stable component supply and long-term industrial availability.

Supply support for UCC28050 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 company specializing in analog and embedded processing technologies, with leadership in power management ICs and industrial-grade reliability.

The UCC28050 belongs to TI's legacy PFC controller product line, designed specifically for cost-sensitive, low-to-medium power transition-mode boost applications requiring IEC 61000-3-2 compliance and minimal external components.

FAQ

What is the recommended V_CC bypass capacitor value for UCC28050?

The UCC28050 datasheet specifies a minimum 0.1 µF high-frequency ceramic capacitor between VCC and GND. For robust start-up under low-line conditions, a 1 µF X7R ceramic is recommended - leveraging the 15.8 V UVLO to ensure reliable turn-on even with slow-rising V_CC. Larger values (e.g., 2.2 µF) improve ripple rejection but increase start-up time; the UCC28050's 75 µA start-up current supports high-impedance charging paths.

How does the zero-power detect feature work in UCC28050?

The UCC28050 activates zero-power detect when the COMP pin voltage falls below 2.3 V, latching the DRV output low to prevent overvoltage during no-load or light-load conditions. This occurs because the transconductance amplifier's output drops as output voltage rises above regulation, and the internal comparator monitors COMP directly. Unlike external OVP circuits, this function requires no additional components and responds within microseconds of COMP crossing threshold.

Can UCC28050 be used in continuous conduction mode (CCM)?

No - the UCC28050 is architecturally designed exclusively for transition-mode (boundary-conduction mode) operation. It relies on ZCD pin detection to trigger switch turn-on at inductor zero-current crossings, and lacks the oscillator, ramp generator, or fixed-frequency timing circuitry required for CCM control. Attempting CCM use results in unstable operation, excessive current stress, and failure to meet harmonic standards.

What is the maximum allowable voltage on the MULTIN pin of UCC28050?

The MULTIN pin has an absolute maximum rating of 5 V and a recommended operating range of 0–2.5 V at high line. Exceeding 2.5 V risks distortion in the multiplier output and increased THD; exceeding 5 V may damage the internal circuitry. A resistive divider from the rectified AC line must be sized so that peak MULTIN voltage stays ≤2.5 V - typically achieved with 1 MΩ top resistor and 10 kΩ bottom resistor for 265 V_AC input.

Does UCC28050 support interleaved PFC operation?

No - the UCC28050 is a single-channel transition-mode PFC controller with no phase-shift or synchronization capability. It lacks dedicated sync pins, programmable dead-time control, or master/slave configuration logic required for interleaving. For interleaved designs, TI recommends multi-channel controllers such as UCC28070 or discrete solutions with external clock synchronization.