Texas Instruments UCC28056DBVT

Overview

UCC28056DBVT from Texas Instruments is a 6-pin SOT-23 transition-mode (TM) and discontinuous conduction mode (DCM) power factor correction (PFC) controller for single-phase AC-DC front ends. It delivers <80 mW no-load input power at 230 VAC, supports up to 300 W PFC stages, and features valley-synchronized MOSFET turn-on, burst-mode operation with soft entry/exit, and dual output over-voltage protection. It enables PFC-always-on architectures in desktop computing and LED driver systems.

For engineers reviewing the UCC28056DBVT datasheet, UCC28056DBVT pinout, UCC28056DBVT application, or UCC28056DBVT equivalent, key selection criteria include ultra-low standby power capability, multi-mode TM/DCM control logic, ZCD-based valley detection timing, integrated thermal shutdown, and compatibility with LLC controllers like UCC256403/4 for full-system efficiency optimization.

Technical Context

The UCC28056DBVT implements mixed-mode control: it operates in transition mode at full load and automatically transitions into DCM as load decreases, reducing switching frequency without disabling PFC. Its ZCD/CS pin performs dual functions-current sensing during DRV high and drain voltage monitoring during DRV low-to enable line feed-forward, brown-in detection, valley synchronization, and second-level OVP.

Control logic includes an enhanced transconductance error amplifier (g_M = 50 µS typical, 300 µS for large errors), programmable burst thresholds (V_BSTFALL = 0.5 V, V_BSTRISE = 0.625 V), and user-adjustable valley delay via external RDG resistors (7 selectable delays from 170 ns to 457 ns). Thermal shutdown activates at 135–155°C with 40°C hysteresis.

Key Specifications

Pinout & Package

SOT-23 (DBV) package: 6-pin, 2.90 mm × 1.6 mm body size, surface-mount, thermally enhanced layout with GND pin at position 4 for optimal noise immunity and current sense reference.

Key Features

Applications

Equivalent & Alternatives

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

Compared with UCC28056DBVT, UCC28056A adds mandatory second-level OVP and tighter OVP1 tolerance for safety-critical bus regulation, while UCC28056C retains identical functional timing but improves ZCD noise rejection - both require no PCB changes but offer higher system-level reliability in electrically noisy environments.

Availability

UCC28056DBVT is available at Aetrix Electronics and suitable for desktop computing, digital TV, gaming adapter, LED luminaire, and industrial charger applications requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.

Supply support for UCC28056DBVT 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 power management solutions with deep expertise in energy-efficient power conversion.

The UCC28056 product line targets high-efficiency, low-standby-power AC-DC front ends for consumer and industrial applications, emphasizing simplified PFC design, reduced BOM cost, and green standard compliance without auxiliary circuitry.

FAQ

What is the primary function of the ZCD/CS pin on the UCC28056DBVT?

The ZCD/CS pin on the UCC28056DBVT serves two critical roles: during DRV high, it senses voltage across the current sense resistor (RCS) for cycle-by-cycle over-current protection; during DRV low, it monitors the MOSFET drain waveform to detect zero-current crossing for valley-synchronized turn-on, implement line voltage feed-forward, and support second-level output over-voltage protection. This dual functionality eliminates the need for separate sensing paths.

How does the UCC28056DBVT achieve <80 mW no-load power at 230 VAC?

The UCC28056DBVT achieves <80 mW no-load input power through ultra-low startup current (<46 µA), burst-mode operation with soft entry/exit, multi-mode control that reduces switching frequency at light loads, and integrated low-power states (BstOffb) triggered when COMP voltage drops below 0.5 V. When paired with UCC256403/4 LLC and UCC24624 synchronous rectifier, the full system sustains PFC-always-on operation without auxiliary converter.

Can the UCC28056DBVT drive a 300 W PFC stage without external gate drivers?

Yes, the UCC28056DBVT can drive a 300 W PFC stage directly: its DRV pin delivers −0.7 A source and 1 A sink peak current, with output voltage clamped to 10–15 V depending on VCC. For typical 600 V, 25 mΩ Si MOSFETs used in 300 W designs, this drive strength ensures adequate dV/dt control and gate charge delivery without external buffers - confirmed in TI's UCC28056DBVT reference design TIDA-01622.

What is the purpose of the RDG resistor network connected to the DRV pin of the UCC28056DBVT?

The RDG resistor network between DRV and GND on the UCC28056DBVT selects one of eight valley delay settings (TZCDR0–TZCDR7), ranging from 170 ns to 457 ns. This fine-tunes the timing offset between ZCD detection and DRV rising edge, ensuring precise alignment of MOSFET turn-on to the drain voltage valley across varying line voltages, load conditions, and inductor resonant frequencies - critical for minimizing switching loss.

Does the UCC28056DBVT include thermal protection, and how does it behave?

Yes, the UCC28056DBVT includes integrated thermal protection: it shuts down when junction temperature exceeds 135–155°C (TTSDRise), and resumes operation only after temperature falls below 95–115°C (TTSDFall), providing 38–42°C hysteresis. During shutdown, DRV goes low, COMP discharges via 4.3–5.7 kΩ internal resistor, and ICC drops to 132 µA - protecting both the UCC28056DBVT and connected power stage from thermal runaway.