Texas Instruments UCC3817APW

Overview

UCC3817APW from Texas Instruments is a BiCMOS average current-mode power factor correction (PFC) controller for boost preregulators, delivering near-unity power factor in 250-W PC and industrial power supplies. It features 16-V/10-V UVLO thresholds, 7.5-V precision reference output, ±1.2-A peak gate drive, 6–220-kHz programmable oscillator frequency, and integrated overvoltage protection with 500-mV hysteresis.

For engineers reviewing the UCC3817APW datasheet, UCC3817APW pinout, UCC3817APW application, or UCC3817APW equivalent, this controller supports IEC61000-3-2 compliance below 300 W, enables leading-edge modulation to reduce bulk capacitor ripple, and provides accurate power limiting via PKLMT pin with 15-mV threshold sensitivity.

Technical Context

The UCC3817APW implements average current-mode control using a high-gain (90 dB), low-offset (±2 mV) current amplifier and a three-input analog multiplier (VAOUT, IAC, VFF) to shape line current waveform. Its zero-power comparator monitors VAOUT and latches DRVOUT low when voltage falls below 0.33 V - enabling light-load efficiency optimization.

Oscillator frequency is set by RT and CT pins per f ≈ 0.6/(RT × CT), supporting 80–120 kHz total variation across line and temperature. The 16-pin TSSOP (PW) package integrates a shunt-regulated VREF output, UVLO with 6.3-V hysteresis, and OVP/EN window comparator with 1.9-V enable threshold and 0.5-V hysteresis.

Key Specifications

Pinout & Package

TSSOP-16 (PW) package: 5.00 mm × 4.40 mm body, 0.65-mm pitch, surface-mount, RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar power factor correction controller applications.

Compared with UCC3817APW, UCC3817AD offers lower junction-to-ambient thermal resistance but occupies more PCB area, while UCC2817APW extends operational temperature range without altering layout or firmware - making it suitable for harsh environments where reliability trumps cost.

Availability

UCC3817APW is available at Aetrix Electronics and suitable for PC power supplies, consumer electronics adapters, and industrial power modules requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for UCC3817APW 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 designing analog ICs, embedded processors, and power management solutions for industrial, automotive, and communications markets.

The UCC3817APW belongs to TI's UCCx81xA BiCMOS PFC controller family, engineered specifically for high-efficiency, average-current-mode boost preregulators targeting IEC61000-3-2 compliance in sub-300-W systems.

FAQ

What is the operating temperature range for the UCC3817APW?

The UCC3817APW is specified for operation from 0°C to 70°C ambient temperature. This commercial-grade rating aligns with its intended use in PC power supplies and consumer electronics where thermal management is controlled. For extended-range applications, the pin-compatible UCC2817APW supports –40°C to 85°C.

Does the UCC3817APW support direct connection to a MOSFET gate without external drivers?

Yes, the UCC3817APW integrates a ±1.2-A peak totem-pole gate driver on DRVOUT. It can directly drive medium-size MOSFETs, though a series gate resistor (typically 10–22 Ω) is recommended to damp ringing caused by parasitic inductance and gate capacitance.

How does the UCC3817APW implement power factor correction?

The UCC3817APW uses average current-mode control: it senses input line current via CAI/MOUT, compares it to a feed-forward–scaled reference from the multiplier (IAC × VAOUT / VFF²), and adjusts PWM duty cycle to force line current to track line voltage waveform - achieving >0.99 PF in validated 250-W designs.

What is the purpose of the PKLMT pin on the UCC3817APW?

The PKLMT pin on the UCC3817APW serves as the peak current limit comparator input. When the voltage at PKLMT falls below 0 V (with ±15 mV threshold accuracy), the controller immediately terminates the current switching cycle - providing cycle-by-cycle overcurrent protection for the boost switch.

Can the UCC3817APW be used in critical conduction mode (CRM) designs?

No - the UCC3817APW is designed exclusively for continuous conduction mode (CCM) average current-mode control. CRM operation requires different control architecture (e.g., zero-current detection), and TI recommends UCC38050/1 or UCC3819 for CRM-based PFC designs.