Texas Instruments TPS92074DDCT

Overview

TPS92074DDCT from Texas Instruments is a non-isolated buck PFC LED driver IC with digital reference control, designed for constant-current LED lighting without phase-dimming compatibility. It delivers 50/60 Hz line synchronization, regulated average LED current (via ISNS sense resistor), and constant off-time switching with emulated spread-spectrum EMI reduction. Used in bulb-replacement LED lamps requiring >0.9 power factor and low THD.

For engineers reviewing the TPS92074DDCT datasheet, TPS92074DDCT pinout, TPS92074DDCT application, or TPS92074DDCT equivalent, key selection criteria include VSEN-based line sync accuracy (±0.035 V threshold hysteresis), ISNS current limit threshold (500 mV typical), COFF-controlled off-time (280 µs max), thermal shutdown at 160°C, and support for 6-pin TSOT-23-6 packaging with GATE drive capability up to 18 V.

Technical Context

The TPS92074DDCT implements a patent-pending digital controller that samples VSEN to detect AC line zero-crossings and generate a synchronized triangular reference waveform (0–1 V range, 127-level DAC) for high-PF current regulation. Its hysteretic peak-current control uses ISNS voltage comparison against this dynamic reference to set per-cycle peak inductor current.

Switching is governed by constant off-time (set via COFF capacitor and internal 1.2 V threshold), while gate drive (GATE pin) features 3–8 Ω sourcing/sinking resistance and 33 ns delay from ISNS limit detection. The architecture inherently varies switching frequency to ease EMI filtering requirements and supports single-winding magnetic configurations without auxiliary windings.

Key Specifications

Pinout & Package

TPS92074DDCT is packaged in a 6-pin TSOT-23-6 (DDC) surface-mount package with exposed pad for thermal dissipation. Pin 1 is VSEN, Pin 2 is GND, Pin 3 is ISNS, Pin 4 is GATE, Pin 5 is VCC, and Pin 6 is COFF. No NC pins; all six terminals are functional and electrically assigned.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar non-dimming LED driver applications.

Compared with MP4007GQ and NCL30001DR2G, the TPS92074DDCT uniquely integrates digital line synchronization, DAC-generated triangular reference, and constant off-time control in a 6-pin package-enabling simpler, lower-cost, single-stage buck PFC designs for sub-20 W non-dimming LED lamps without sacrificing PF or THD performance.

Availability

TPS92074DDCT is available at Aetrix Electronics and suitable for non-phase-dimmable LED lamps, bulb replacement modules, and area lighting applications requiring stable component supply, long-lifecycle availability, and consistent parametric performance across production batches.

Supply support for TPS92074DDCT 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, embedded processing, and power management technologies, with decades of leadership in LED driver innovation and automotive-grade reliability standards.

The TPS92074DDCT belongs to TI's LED lighting controller product line, engineered specifically for cost-sensitive, high-efficiency AC-DC LED drivers that prioritize power factor correction, EMI reduction, and compact form factor over phase-dimming functionality.

FAQ

What is the primary function of the VSEN pin on the TPS92074DDCT?

The VSEN pin on the TPS92074DDCT serves as the dedicated AC line voltage sensing input for digital synchronization. It detects rising and falling edges of the rectified AC waveform to determine line frequency (45–65 Hz) and trigger generation of the synchronized triangular reference waveform. With nominal thresholds of 1.0 V (rising) and 0.5 V (falling), it enables the TPS92074DDCT to achieve high power factor without external timing components or phase-locked loops.

How does the TPS92074DDCT achieve power factor correction without a traditional feedback loop?

The TPS92074DDCT achieves power factor correction using a patent-pending digital architecture that generates a line-synchronized triangular reference (0–1 V, 127-level DAC) based on VSEN input. This reference dynamically modulates the ISNS current limit threshold across each AC half-cycle, shaping the input current waveform to closely follow the sinusoidal line voltage. Unlike conventional controllers, it requires no secondary-side feedback, optocoupler, or error amplifier-reducing component count and cost while maintaining >0.9 PF.

Can the TPS92074DDCT operate without the VSEN connection?

Yes, the TPS92074DDCT can operate with VSEN grounded, entering a simplified mode that uses a static 0.394 V (50/127) reference instead of the triangular ramp. In this configuration, power factor remains >0.9 when combined with an on-time clamp and appropriate LED stack voltage, though THD increases due to loss of line-synchronized current shaping. This mode is intended for ultra-low-BOM-count applications where minimal component count outweighs strict THD requirements.

What is the role of the COFF pin in TPS92074DDCT operation?

The COFF pin on the TPS92074DDCT sets the constant off-time duration for each switching cycle via an external capacitor. An internal 1.2 V comparator and 33–60 Ω pull-down resistor define t_OFF = C_COFF × R_COFF × ln(1.2/V_CC). This variable off-time creates inherent switching frequency variation, producing an emulated spread-spectrum effect that eases EMI filter design and allows smaller input filter components compared to fixed-frequency controllers.

Does the TPS92074DDCT support buck-boost topology?

Yes, the TPS92074DDCT supports both buck and buck-boost topologies. For buck-boost operation, the VSEN pin must be connected to the bridge tap or LED(–) node to ensure adequate conduction time (>5.9 ms) for triangular reference activation-especially critical when LED stack voltage exceeds 65 V. The controller's digital architecture adapts seamlessly, maintaining constant-current regulation and PFC performance regardless of topology, provided the external magnetics and layout meet TI's design guidelines.