Texas Instruments UCC28600D

Overview

UCC28600 from Texas Instruments is an 8-pin SOIC quasi-resonant flyback green-mode PWM controller for AC-DC power supplies up to 200 W. It delivers low standby current (≤550 μA), programmable soft-start, and true-drive gate output (1-A sink / –0.75-A source) to drive primary-side MOSFETs in energy-efficient adapters and LCD TV bias supplies.

For engineers reviewing the UCC28600 datasheet, UCC28600 pinout, UCC28600 application, or UCC28600 equivalent, key selection criteria include its multi-mode operation (QR/FFM/Green), valley-switching EMI reduction, line/load OVP programmability, and integrated thermal shutdown - all validated across –40°C to +105°C junction temperature.

Technical Context

The UCC28600 implements current-mode control with cycle-by-cycle power limiting and valley-synchronized switching detection. Its FB pin voltage (0.3–1.6 V threshold range) directly selects operating mode: green-mode burst (≤10% load), frequency foldback (10–30% load), or quasi-resonant/DCM (≥30% load).

It integrates a 13-V clamped gate driver, internal 20-kΩ FB pullup, programmable soft-start via external capacitor, and open-drain STATUS pin for PFC disable coordination. Protection includes line/load OVP (via OVP pin), overcurrent hiccup restart, and thermal shutdown at 140°C with 15°C hysteresis.

Key Specifications

Pinout & Package

UCC28600 is housed in an 8-pin SOIC (D package) with 4.90 mm × 3.91 mm body size and standard 1.27 mm pitch. Thermal resistance is R_θJA = 108.9°C/W.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar quasi-resonant flyback controller applications.

Compared with UCC28600, UCC28610 reduces external component count via integrated HV startup but shares identical QR timing and protection architecture; NCP1337 offers simpler control but lacks the precise light-load efficiency and system-level coordination (e.g., PFC disable) enabled by UCC28600's STATUS and OVP pins.

Availability

UCC28600 is available at Aetrix Electronics and suitable for LCD-TV bias supplies, AC-DC adapters, and off-line battery chargers requiring stable component supply, long-term lifecycle support, and full traceability for industrial and consumer OEM programs.

Supply support for UCC28600 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 and embedded processing technologies, with decades of power management IC innovation.

The UCC28600 belongs to TI's green-mode flyback controller product line, designed specifically for high-efficiency, low-standby-power AC-DC conversion in consumer and industrial power supplies up to 200 W.

FAQ

What is the purpose of the STATUS pin on the UCC28600?

The STATUS pin on the UCC28600 is an active-high open-drain output that signals entry into green mode (standby). When FB falls below 0.5 V, STATUS goes high-impedance; when FB rises above 1.4 V, it pulls low. This pin is used to disable upstream PFC controllers - for example, by turning off a bias FET - thereby reducing total system no-load power. The UCC28600 STATUS pin behavior is fully specified in the Electrical Characteristics table with R_DS(on) = 2.4 kΩ typical and leakage <2.0 μA.

How does the UCC28600 implement quasi-resonant switching?

The UCC28600 implements quasi-resonant switching by detecting the valley of the drain resonant waveform via the OVP pin, synchronized with internal QR_DONE timing. It triggers the OUT pin only at minimum drain voltage points, reducing switching losses and EMI. This valley detection is validated across line voltages and load conditions, with maximum QR frequency at 130 kHz and minimum at 40 kHz. The UCC28600 does not require external zero-current detection circuitry - all QR timing is handled internally with built-in hysteresis and blanking.

Can the UCC28600 be used without an optocoupler?

No - the UCC28600 requires an optocoupler for closed-loop regulation. Its FB pin is designed as a current-input node with an internal 20-kΩ pullup to 5 V, intended to interface directly with the collector of a photo-transistor. Primary-side regulation schemes (e.g., using auxiliary winding sensing) are not supported; the UCC28600 relies on isolated feedback to set peak current and modulate switching frequency. Attempting to operate the UCC28600 without optocoupler feedback will result in unregulated output and potential overvoltage conditions.

What is the recommended VDD bypass capacitor value for the UCC28600?

The recommended VDD bypass capacitor for the UCC28600 is a 0.1-μF ceramic capacitor placed as close as possible between Pin 6 (VDD) and Pin 4 (GND). This value is specified in the Recommended Operating Conditions table and ensures stable internal regulation under transient load conditions. A larger bulk capacitor (e.g., 1–10 μF) may be added in parallel for improved hold-up during line dips, but the 0.1-μF ceramic remains mandatory for high-frequency noise suppression. Deviating from this value risks erratic gate drive or UVLO oscillation.

Does the UCC28600 support both line and load overvoltage protection?

Yes - the UCC28600 supports independent line and load overvoltage protection via its dedicated OVP pin. Line-OVP is triggered by negative current injection (–450 μA typical) from the primary bias winding, while load-OVP responds to positive voltage (3.75 V typical) referenced to the OVP pin. These functions are implemented in separate fault logic blocks and can be configured with distinct resistor dividers. Both protections cause immediate shutdown with hiccup restart, and their thresholds are characterized over temperature - confirming reliable operation in UCC28600-based power supplies meeting UL 62368-1 and IEC 62368-1 requirements.