Texas Instruments UCC2817PW

Overview

UCC2817PW from Texas Instruments is a BiCMOS average current-mode PFC controller for boost preregulators, delivering near-unity power factor (0.999), <3% THD, and 6–220 kHz programmable switching frequency. It integrates a 7.5-V reference, overvoltage protection, soft-start, and leading-edge modulation to reduce bulk capacitor ripple. Used in universal-input AC/DC front-ends for industrial SMPS and server power supplies.

For engineers reviewing the UCC2817PW datasheet, UCC2817PW pinout, UCC2817PW application, or UCC2817PW equivalent, key selection considerations include its 16-V UVLO turn-on threshold, 150-µA start-up current, ±2-mV current amplifier offset, 93–99% max duty cycle, and TSSOP-16 (PW) package compatibility with high-density PFC layouts.

Technical Context

The UCC2817PW implements average current mode control using a dual-loop architecture: a voltage error amplifier regulates output DC bus (e.g., 385 V), while a wide-bandwidth current amplifier shapes line current via multiplier-derived reference. Its analog multiplier accepts IAC (up to 500 µA), VFF (feed-forward RMS voltage), and VAOUT to generate IMOUT - a current command that drives the PWM latch.

Leading-edge modulation, integrated shunt regulator (for bootstrap supply), and zero-power comparator (0.33-V threshold) enable stable light-load operation and reduced conduction loss. The device operates from 12–17 V on VCC, features 100-kHz typical oscillator accuracy (±15%), and supports precise power limiting via PKLMT pin with 0-V threshold referenced to GND.

Key Specifications

Pinout & Package

TSSOP-16 (PW) package: 5.0 mm × 4.4 mm, 0.65 mm pitch, exposed thermal pad (not electrically connected), RoHS-compliant, rated for −40°C to +85°C ambient.

Key Features

Applications

Equivalent & Alternatives

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

Compared with UCC2817PW, UCC28070DR offers superior THD performance and digital calibration but mandates external VCC generation, while ICE3PCS01G enables direct high-voltage startup but sacrifices the 7.5-V reference and soft-start flexibility critical for compact, low-component-count PFC stages.

Availability

UCC2817PW is available at Aetrix Electronics and suitable for industrial AC/DC power supplies, server front-end rectifiers, and medical equipment power modules requiring stable component supply and long-term lifecycle support.

Supply support for UCC2817PW 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, embedded processing, and power management ICs, with decades of expertise in power conversion and energy-efficient design.

The UCC2817PW belongs to TI's legacy PFC controller product line, engineered specifically for high-efficiency, high-reliability active power factor correction in universal-input AC/DC power supplies targeting industrial, computing, and medical markets.

FAQ

What is the UVLO behavior of the UCC2817PW?

The UCC2817PW features an under-voltage lockout with 16-V turn-on threshold and 9.7-V turn-off threshold, providing 6.3-V hysteresis. This ensures clean startup once the bulk capacitor reaches sufficient voltage and prevents erratic operation during brownouts. The shunt regulator remains active only when VCC exceeds the UVLO threshold, making it ideal for bootstrap supply configurations in the UCC2817PW.

How does the UCC2817PW achieve near-unity power factor?

The UCC2817PW achieves near-unity power factor through average current mode control: the voltage error amplifier (VAOUT) sets the amplitude reference, while the analog multiplier combines VAOUT, IAC (line voltage proportional current), and VFF (feed-forward RMS voltage) to generate IMOUT - a precise current command. This forces the boost inductor current to track the sinusoidal line voltage waveform, achieving 0.999 PF and <3% THD in well-designed implementations of the UCC2817PW.

Can the UCC2817PW be used with a fixed 12-V supply instead of bootstrap?

No - the UCC2817PW variant is specifically designed for bootstrap operation with its integrated shunt regulator and 16-V UVLO. For fixed 12-V supply applications, TI specifies the UCC2818PW (10.2-V UVLO, no shunt regulator). Using UCC2817PW with a fixed 12-V rail risks failure to start or unstable regulation, as its internal shunt is optimized for self-biasing from the boost output. Always match supply topology to the correct variant: UCC2817PW for bootstrap, UCC2818PW for fixed supply.

What is the function of the PKLMT pin on the UCC2817PW?

The PKLMT pin on the UCC2817PW serves as the peak current limit comparator input with a 0-V threshold. It connects to a resistor divider from the low-side current sense resistor to VREF, level-shifting the sensed voltage so that the comparator triggers when sensed current exceeds the programmed limit. This provides cycle-by-cycle overcurrent protection for the boost switch, ensuring safe operation under overload or short-circuit conditions in every UCC2817PW-based design.

Does the UCC2817PW support programmable soft-start?

Yes - the UCC2817PW implements programmable soft-start via the SS pin, which sources a −10-µA (typ) current to charge an external capacitor. The resulting ramp voltage replaces VAOUT during startup, gradually increasing PWM duty cycle to prevent output voltage overshoot and inrush current. A 10-nF capacitor yields ~7.5-ms delay, and the SS pin discharges rapidly during VCC dropout or OVP/EN assertion, ensuring controlled shutdown in the UCC2817PW.