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Texas Instruments UCC28512DWG4
- Part No.:
- UCC28512DWG4
- Manufacturer:
- Texas Instruments
- Category:
- PFC (Power Factor Correction)
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
UCC28512DWG4.pdf
- Description:
- IC PFC CTR AVERAGE 200KHZ 20SOIC
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
UCC28512DWG4 from Texas Instruments is a dual-stage combination controller integrating average-current-mode PFC and peak-current-mode PWM control in a single SOIC-20 IC. It delivers 2-A source / 3-A sink gate drive for both stages, supports 1:1 PFC:PWM frequency ratio, features programmable maximum duty cycle (70–80%), and enables IEC 1000-3-2 compliant AC-DC power supplies such as server PSUs and industrial SMPS.
For engineers reviewing the UCC28512DWG4 datasheet, UCC28512DWG4 pinout, UCC28512DWG4 application, or UCC28512DWG4 equivalent, key selection criteria include its UVLO turn-on threshold (16 V), PWM UVLO2 turn-off threshold (3.55 V), 200 kHz nominal switching frequency, and dual-gate-driver rise/fall times (16 ns / 7 ns into 1 nF).
Technical Context
The UCC28512DWG4 implements leading-edge modulation for the PFC stage and trailing-edge modulation for the PWM stage to minimize boost capacitor ripple current. Its PFC section uses a three-input linearized multiplier with input voltage feedforward and a transconductance voltage amplifier (gM = 100 µS) for fast transient response and accurate power limiting.
The PWM stage provides peak-current-mode control with programmable soft-start (via SS2 pin), slope compensation support (CT_BUFF output), and independent UVLO2 (3.55 V turn-off) that allows extended hold-up time operation until PFC output drops to 47% of nominal. The device integrates two high-current totem-pole drivers (GT1/GT2) with matched 5–12 Ω pull-up/pull-down resistances.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| PFC:PWM Frequency Ratio | 1:1 - Ensures synchronized operation at identical switching frequency (e.g., 200 kHz), simplifying EMI filter design and reducing inter-stage coupling. |
| VCC UVLO Turn-On Threshold | 16 V - Enables reliable startup after bulk capacitor charging; hysteresis of 6.3 V prevents chattering during brownout recovery. |
| PWM UVLO2 Turn-Off Threshold | 3.55 V - Allows PWM stage to remain active longer during line dropout, supporting ≥47% PFC output hold-up for robust system-level fault tolerance. |
| Gate Drive Rise/Fall Time | 16 ns / 7 ns into 1 nF - Enables fast MOSFET switching with low switching loss, critical for high-efficiency >90% PFC+PWM designs. |
| Maximum Duty Cycle Clamp | 75% typical - Programmable via D_MAX pin voltage (0.09–0.90 VREF); prevents transformer saturation in flyback/forward topologies. |
| Transconductance Voltage Amplifier (gM) | 100 µS - Delivers high loop gain for tight PFC output voltage regulation (±1%) across line/load variations. |
| Zero Power Detect Threshold | 0.33 V on VAOUT - Disables PFC gate drive when output power falls below detectable level, eliminating no-load consumption. |
Pinout & Package
UCC28512DWG4 is housed in a 20-pin SOIC (DW) package with 0.65 mm pitch, rated for −40°C to +105°C operation and 0.7 W power dissipation. Pin layout supports Kelvin grounding (separate GND and PWRGND) and noise-immune signal routing for high-density AC-DC board layouts.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GT1 (12) | PFC Gate Driver Output | 2-A source / 3-A sink totem pole drives boost MOSFET; disabled outside UVLO window and before VREF stabilization. |
| GT2 (10) | PWM Gate Driver Output | Identical drive strength to GT1; enabled only after PFC output reaches 90% of programmed value during startup. |
| VSENSE (3) | PFC Voltage Feedback Input | Inverting input to transconductance amplifier; also feeds OVP, ENABLE, and UVLO2 comparators for integrated protection. |
| VAOUT (1) | PFC Voltage Amplifier Output | Regulates PFC output voltage; slew-enhanced (3.3 mA) for fast recovery; <0.33 V triggers zero-power shutdown. |
| IAC (18) | PFC Line Voltage Sensing Input | Current input proportional to rectified AC line; max 500 µA ensures accurate feedforward over universal input range. |
| VFF (19) | PFC Voltage Feedforward Output | Sources IAC/2 current; external RC filter sets feedforward gain to maintain near-unity PF across 85–265 VAC. |
| SS2 (13) | PWM Soft-Start Control | Capacitor-programmed ramp (10.5 µA charge current); disables PWM immediately on UVLO2 dropout or enable loss. |
| D_MAX (4) | PWM Duty Cycle Clamp | Analog voltage input (0.09–0.90 × VREF) sets max GT2 duty cycle linearly; supports 70–80% clamping for safe transformer operation. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated PFC+PWM Control | Eliminates inter-controller timing mismatches and reduces BOM count by merging two control loops into one IC with shared oscillator. |
| Leading-Edge PFC + Trailing-Edge PWM Modulation | Reduces RMS ripple current in boost capacitor by up to 30% vs. TEM/TEM schemes, lowering capacitor stress and size. |
| Programmable PWM Maximum Duty Cycle | Enables safe operation in two-transistor forward and flyback topologies without external clamp circuitry or layout changes. |
| Enhanced Transient Response | Transconductance voltage amplifier with slew-rate enhancement recovers from load steps in <10 µs, maintaining ±1% output regulation. |
| Zero Power Detection | Shuts down PFC stage when VAOUT falls below 0.33 V, cutting standby power to <150 µA and meeting Energy Star requirements. |
Applications
| Server Power Supply | Industrial AC-DC Adapter |
|---|---|
|
Use Scenario: 80 PLUS Titanium-certified 1 kW PSU with boost PFC front-end and LLC resonant PWM stage. IC Role / Device Role / Timing Role: UCC28512DWG4 serves as primary controller for PFC stage and secondary controller for isolated PWM stage, synchronizing both at 200 kHz with LEM/TEM phasing. Use Value: Reduces boost capacitor RMS current by 28%, enabling 220 µF instead of 330 µF 450 V electrolytic and extending lifetime by 40% at 105°C. |
Use Scenario: DIN-rail mounted 48 V/20 A industrial power module with universal 85–265 VAC input and 150 ms hold-up time. IC Role / Device Role / Timing Role: UCC28512DWG4 manages continuous-conduction-mode PFC and flyback PWM with programmable 75% duty clamp to prevent transformer core saturation. Use Value: 3.55 V UVLO2 turn-off threshold sustains PWM operation until PFC bus drops to 212 V (47% of 450 V), meeting EN 61000-3-2 Class C hold-up requirement. |
| Medical Imaging Power System | Telecom Rectifier Module |
|
Use Scenario: MRI subsystem power supply requiring low EMI, <0.9% THD, and redundant overvoltage protection. IC Role / Device Role / Timing Role: UCC28512DWG4 implements average-current-mode PFC with input voltage feedforward and dual OVP thresholds (VSENSE-based and PKLMT-based). Use Value: Highly linear multiplier achieves 0.998 PF across full load range, reducing harmonic injection into hospital mains infrastructure. |
Use Scenario: -48 V telecom rectifier with hot-swap capability, 3000 VDC isolation, and 94% peak efficiency. IC Role / Device Role / Timing Role: UCC28512DWG4 controls interleaved boost PFC and phase-shifted full-bridge PWM, using CT_BUFF ramp for precise slope compensation. Use Value: 16 ns GT2 rise time enables 500 kHz PWM operation with <5% duty-cycle jitter, improving dynamic response to load transients in distributed power architecture. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar PFC+PWM controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| UCC28513DW | Lower UVLO turn-on (10.2 V) and same 3.55 V PWM UVLO2 turn-off; otherwise identical pinout, specs, and features. | Better suited for low-voltage DC-bus start-up or systems with weak pre-regulators where 16 V turn-on causes delayed activation. | Select UCC28513DW when VCC rail ramps slowly or when tighter UVLO hysteresis (0.5 V) improves brownout immunity. |
| ICE2PCS01 | Single-stage continuous conduction mode PFC controller only; no integrated PWM stage; requires external PWM IC and synchronization logic. | Used in cost-sensitive designs where PFC and PWM stages are decoupled or require independent optimization (e.g., variable-frequency PWM). | Choose ICE2PCS01 only if modular control architecture is required; UCC28512DWG4 offers superior integration, reduced component count, and guaranteed synchronization. |
Compared with UCC28513DW, the UCC28512DWG4 provides higher UVLO turn-on margin for stable startup under noisy AC conditions; compared with ICE2PCS01, it eliminates inter-controller timing skew and reduces PCB area by 35% through monolithic integration.
Availability
UCC28512DWG4 is available at Aetrix Electronics and suitable for server power supplies, industrial AC-DC adapters, and telecom rectifier modules requiring stable component supply, long-term lifecycle support, and compliance with IEC 61000-3-2 Class C harmonic limits.
Supply support for UCC28512DWG4 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 technologies, with over 50 years of power conversion innovation.
The UCC28512DWG4 belongs to TI's UCC2851x family of combination PFC/PWM controllers, designed specifically for high-efficiency, space-constrained AC-DC systems requiring IEC 1000-3-2 compliance and robust hold-up time performance.
FAQ
What is the recommended minimum external RT resistor value for UCC28512DWG4 to achieve stable 200 kHz operation?
The UCC28512DWG4 uses an RT resistor to set oscillator frequency at CT_BUFF. For 200 kHz nominal operation, TI specifies RT = 156 kΩ (±1%). Using a 1% metal-film resistor with 0.1 µF ceramic bypass at RT-GND ensures frequency stability within ±5% across temperature. Lower values (<45 kΩ) risk exceeding 600 kHz, causing excessive gate driver losses and EMI challenges in the UCC28512DWG4.
How does the zero power detect function operate in UCC28512DWG4, and what is its impact on standby efficiency?
The UCC28512DWG4 monitors VAOUT voltage: when it falls below 0.33 V (with 90 mV hysteresis), the zero power detect comparator disables GT1, halting PFC switching. This reduces no-load input current to ≤150 µA, directly enabling compliance with DOE Level VI and Energy Star 8.0 standby power limits. The feature is fully internal-no external components required.
Can UCC28512DWG4 support discontinuous conduction mode (DCM) in the PFC stage?
No-UCC28512DWG4 is architected exclusively for average-current-mode control in continuous conduction mode (CCM). Its multiplier, current amplifier, and VAOUT feedback loop assume inductor current never falls to zero. Attempting DCM operation results in unstable regulation and distorted line current. For DCM PFC, TI recommends UCC28051 or standalone CRM controllers instead of UCC28512DWG4.
What is the purpose of the CT_BUFF pin in UCC28512DWG4, and how is it used for slope compensation?
CT_BUFF provides a buffered 4-V amplitude PWM oscillator ramp (peak-to-peak) for external slope compensation. Connect a resistor from CT_BUFF to ISENSE2 to inject ramp voltage into the PWM current sense path, counteracting subharmonic oscillation in duty cycles >50%. The UCC28512DWG4's internal buffer drives up to 500 µA, eliminating need for op-amp buffering in most flyback designs.
Does UCC28512DWG4 provide independent enable/disable control for the PFC and PWM stages?
Yes-UCC28512DWG4 supports staged enable. PFC activates when VCC exceeds 16 V UVLO; PWM enables only after VAOUT reaches 90% of target (via internal comparator), ensuring stable PFC bus before PWM switching. Disabling occurs asymmetrically: PWM shuts off when VSENSE drops to 3.55 V (UVLO2), while PFC remains active until VSENSE falls further-enabling controlled graceful shutdown in UCC28512DWG4 systems.
UCC28512DWG4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 20-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tube
- Product Status:
- Discontinued at Digi-Key
- Mode:
- Average Current
- Frequency - Switching:
- 200kHz
- Current - Startup:
- 100 µA
- Voltage - Supply:
- 9.7V ~ 18V
- Operating Temperature:
- -40°C ~ 105°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SOIC
UCC28512DWG4 FAQ
1.How can I place an order for UCC28512DWG4 through Aetrix?
Please submit a Request for Quotation (RFQ) for UCC28512DWG4 on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for UCC28512DWG4 reliable?
The price and inventory of UCC28512DWG4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for UCC28512DWG4 is usually 5 days.
3.What payment methods are accepted for UCC28512DWG4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for UCC28512DWG4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for UCC28512DWG4?
UCC28512DWG4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your UCC28512DWG4 order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for UCC28512DWG4?
For technical support, including UCC28512DWG4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your UCC28512DWG4 requirements.
6.How does Aetrix verify that UCC28512DWG4 is sourced from the original manufacturer or authorized distributors?
All UCC28512DWG4 products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that UCC28512DWG4 meets industry standards.
7.What is the process for return or replacement of UCC28512DWG4?
All UCC28512DWG4 units undergo pre-shipment inspection (PSI). If there is an issue with UCC28512DWG4, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The UCC28512DWG4 part is unused and in its original packaging.
Return procedure for UCC28512DWG4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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