Texas Instruments UCC28050D

Overview

UCC28050D from Texas Instruments is a transition-mode (boundary-conduction mode) power factor correction (PFC) controller in an 8-pin SOIC package, designed for boost preregulators in low-to-medium power AC-DC supplies. It features a 2.5 V internal reference, ±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 electronic ballasts and single-stage PFC flyback converters.

For engineers reviewing the UCC28050D datasheet, UCC28050D pinout, UCC28050D application, or UCC28050D equivalent, key selection criteria include its 90 µS transconductance error amplifier, 2.5 V reference accuracy over –40°C to +105°C, ZCD-based self-oscillating timing, and compatibility with external MOSFETs in CRM boost topologies requiring stable output regulation and harmonic reduction.

Technical Context

The UCC28050D implements transition-mode control via zero-current detection (ZCD pin) to initiate each switching cycle and current-sense (CS pin) comparison to terminate it-eliminating need for external clock or ramp generation. Its transconductance error amplifier (g_M = 90 µS typ.) drives a two-input analog multiplier that shapes input current to match rectified line voltage.

UVLO turn-on at 15.8 V enables fast start-up with small V_CC capacitors, while zero-power detection disables gate drive when COMP falls below 2.3 V-preventing output overvoltage during no-load or light-load conditions without auxiliary sensing circuitry.

Key Specifications

Pinout & Package

UCC28050D is housed in an 8-pin SOIC (D) package with 1.27 mm pitch, JEDEC MS-012AC compliant, rated for 650 mW power dissipation at T_A = 50°C.

Key Features

Applications

Equivalent & Alternatives

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

Compared with UCC28051D and L6561TR, the UCC28050D delivers faster start-up via higher UVLO threshold, built-in zero-power OVP for no-load safety, and tighter 2.5 V reference-making it optimal for standalone PFC applications like electronic ballasts where reliability and regulatory compliance are critical.

Availability

UCC28050D is available at Aetrix Electronics and suitable for electronic ballasts, AC adapter front-ends, desktop PC power supplies, and single-stage PFC flyback converters requiring stable component supply and long-term industrial availability.

Supply support for UCC28050D 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 delivering analog, embedded processing, and connectivity solutions for industrial, automotive, and consumer markets.

The UCC28050D belongs to TI's Transition-Mode PFC Controller product line, engineered specifically for cost-sensitive, low-to-medium power AC-DC systems requiring IEC 61000-3-2 compliance without complex control schemes or external protection components.

FAQ

What is the UVLO turn-on threshold for UCC28050D?

The UCC28050D has a nominal UVLO turn-on threshold of 15.8 V, with a hysteresis of 6.3 V. This higher threshold allows rapid start-up using a smaller V_CC bypass capacitor compared to alternatives like UCC28051D. The specification is guaranteed over temperature and ensures reliable initiation of PFC operation after AC input application. UCC28050D maintains this behavior across its full –40°C to +105°C operating range.

How does UCC28050D prevent output overvoltage at light load?

UCC28050D uses an integrated zero-power detect circuit that monitors the COMP pin voltage. When COMP falls below 2.3 V-indicating very low or no load-the controller latches the DRV output low, halting switching and preventing uncontrolled rise of the boost output voltage. This feature is intrinsic to UCC28050D and requires no external components. UCC28050D also includes secondary OVP activation at VO_SNS > V_REF + 0.19 V for redundant protection.

What is the maximum gate drive current capability of UCC28050D?

UCC28050D provides ±750-mA peak source/sink current on the DRV pin, sufficient to directly drive medium-size N-channel MOSFETs in boost configurations without external buffers. The output uses a totem-pole structure with 5 Ω pull-up and 2 Ω pull-down resistance (typ.), enabling fast rise/fall times (<75 ns with 1 nF load). This drive strength is specified across temperature and supports robust switching in CRM mode where peak currents scale with line voltage.

Does UCC28050D support transition-mode (CRM) operation without external timing components?

Yes, UCC28050D implements fully self-oscillating transition-mode control using internal zero-current detection (ZCD pin) and current-sense (CS pin) comparators-no external oscillator, ramp generator, or timing capacitor is required. The ZCD pin detects inductor demagnetization to trigger each switching cycle, while CS terminates conduction when peak current reaches 1.7 V. This architecture simplifies design and improves line/load transient response versus fixed-frequency alternatives. UCC28050D inherently operates at the boundary between CCM and DCM.

What is the operating temperature range for UCC28050D?

UCC28050D is specified for operation from –40°C to +105°C junction temperature, qualifying it for industrial and lighting applications with elevated thermal environments. Electrical characteristics-including 2.5 V reference voltage (±0.05 V), 90 µS transconductance, and UVLO thresholds-are guaranteed across this full range. The SOIC-8 package has a junction-to-ambient thermal resistance (R_θJA) of 113.6°C/W, supporting reliable performance in convection-cooled layouts without forced air.