Texas Instruments UCC2817N

Overview

UCC2817N from Texas Instruments is a BiCMOS active power factor correction (PFC) controller for boost preregulators, implementing average current-mode control to achieve near-unity power factor and low line-current distortion. It features 7.5-V reference output, 16 V/10 V UVLO thresholds, 0.33-V zero-power detection threshold, and integrated gate driver with 93–99% duty cycle range - deployed in sub-300 W IEC 61000-3-2-compliant PC and industrial power supplies.

For engineers reviewing the UCC2817N datasheet, UCC2817N pinout, UCC2817N application, or UCC2817N equivalent, key selection considerations include its −40°C to +85°C operating temperature range (vs. UCC3817's 0°C to +70°C), UVLO hysteresis of 6.3 V, 7.5-V reference accuracy (±0.131 V over temp), soft-start charge current of −10 µA, and peak current limit sensing via PKLMT pin referenced to 0 V.

Technical Context

The UCC2817N employs average current-mode control using a high-bandwidth current amplifier (CAI/MOUT inputs, CAOUT output) and a three-input analog multiplier (IAC, VFF, VAOUT) to shape input current waveform in phase with rectified AC voltage. Its leading-edge PWM modulation reduces bulk capacitor ripple current when synchronized with downstream DC-DC stages.

It integrates a 7.5-V precision reference (±0.131 V over −40°C to +85°C), voltage error amplifier with 90 dB open-loop gain and 5.5-V clamped output, overvoltage protection with 500 mV hysteresis at OVP/EN, and a totem-pole gate driver (DRVOUT) with 5–12 Ω pull-up and 2–10 Ω pull-down resistance for MOSFET switching.

Key Specifications

Pinout & Package

UCC2817N is housed in a 16-pin PDIP (Plastic Dual In-line Package) with body dimensions 6.35 mm × 19.3 mm. Pin spacing is 2.54 mm, compatible with standard through-hole PCB assembly.

Key Features

Applications

Equivalent & Alternatives

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

Compared with UCC2818N and UCC3817N, the UCC2817N uniquely combines 16-V UVLO for reliable universal-line startup, −40°C to +85°C rating for industrial use, and lowest start-up current (150 µA) - making it the only choice for ruggedized, globally compliant PFC designs.

Availability

UCC2817N is available at Aetrix Electronics and suitable for PC power supplies, industrial AC-DC converters, and LED driver front-ends requiring stable component supply with long-term lifecycle support.

Supply support for UCC2817N 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 power conversion IC design.

The UCC2817N belongs to TI's BiCMOS PFC controller product line, engineered specifically for high-efficiency, low-distortion active power factor correction in universal-input AC-DC power supplies up to 300 W.

FAQ

What is the operating temperature range of the UCC2817N?

The UCC2817N is specified for operation from −40°C to +85°C ambient temperature. This extended range distinguishes it from the UCC3817N (0°C to +70°C) and makes it suitable for industrial, outdoor, and high-reliability power supply applications where thermal margins are critical. The UCC2817N maintains full electrical performance across this range, including reference accuracy and current amplifier offset.

How does the UCC2817N implement overvoltage protection?

The UCC2817N uses a dedicated OVP/EN pin that functions as a window comparator. When the boost output voltage rises above the programmed threshold (VREF + 0.50 V typical), the controller disables DRVOUT to halt switching. It also incorporates 500 mV hysteresis to prevent oscillation near the trip point. If OVP/EN is pulled below 1.9 V, the device resets soft-start and forces immediate shutdown - a feature critical for fault containment in UCC2817N-based systems.

What is the purpose of the PKLMT pin on the UCC2817N?

The PKLMT pin on the UCC2817N serves as the peak current limit comparator input, with a fixed 0 V threshold. It accepts a level-shifted signal from the negative side of the current-sense resistor (via a divider to VREF) to define the precise peak inductor current limit. This architecture allows accurate, temperature-stable current limiting without requiring external op-amps or comparators - a core enabler of stable average current-mode control in the UCC2817N.

Can the UCC2817N be used with discontinuous conduction mode (DCM) boost topologies?

Yes, the UCC2817N supports both continuous conduction mode (CCM) and discontinuous conduction mode (DCM) boost operation. Its average current-mode architecture and wide oscillator range (6–220 kHz) allow stable control across conduction modes. In DCM, the UCC2817N maintains low THD and near-unity power factor by dynamically adjusting duty cycle based on sensed line current and voltage - confirmed in TI's SLUS395K datasheet application examples.

What is the recommended gate resistor value for the DRVOUT pin of the UCC2817N?

Texas Instruments recommends a minimum series gate resistor of 11 Ω for the UCC2817N's DRVOUT pin when VCC = 18 V and peak sink current = 1.2 A, calculated using R_GATE = V_CC/I_MAX − R_pulldown. This value damps ringing, prevents shoot-through in the external MOSFET, and avoids excessive overshoot. Lower values risk instability; higher values increase switching losses. The exact value should be validated with layout parasitics and MOSFET gate charge in the final UCC2817N design.