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Texas Instruments UCC28502DWTRG4
- Part No.:
- UCC28502DWTRG4
- Manufacturer:
- Texas Instruments
- Category:
- PFC (Power Factor Correction)
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
UCC28502DWTRG4.pdf
- Description:
- IC PFC CTR AVERAGE 100KHZ 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,033
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Product details
Overview
UCC28502DWTRG4 from Texas Instruments is a dual-stage active power factor correction (PFC) and DC-DC controller IC integrating average-current-mode PFC with peak-current-mode downstream PWM control. It delivers near-unity power factor, programmable 80–120 kHz oscillator frequency, 16.5 V/10 V UVLO threshold with 6.3 V hysteresis, and synchronized leading-edge (PFC) / trailing-edge (PWM) modulation for reduced bulk-capacitor ripple. It targets universal-input AC-DC front-end designs in industrial and telecom power supplies.
For engineers reviewing the UCC28502DWTRG4 datasheet, UCC28502DWTRG4 pinout, UCC28502DWTRG4 application, or UCC28502DWTRG4 equivalent, key selection criteria include its dual-stage control architecture, wide-input-voltage feedforward (VFF) implementation, 50% max duty cycle clamp on GT2, zero-power detection at 0.33 V on VAOUT, and compatibility with boost + forward topologies requiring coordinated soft-start and overvoltage protection.
Technical Context
The UCC28502DWTRG4 implements average-current-mode control in the PFC stage using IAC current sensing and VFF-based RMS line voltage feedforward to maintain constant input power across 85–265 VRMS inputs. Its analog multiplier divides line current by VFF² to generate MOUT, enabling accurate current shaping without high-voltage components.
The second stage uses peak-current-mode control with external error signal injection via VERR, 50% duty-cycle clamping, and programmable soft-start via SS2. It features independent UVLO2 with 3.0 V hysteresis (enabling operation down to 50% of nominal bulk voltage), pulse-by-pulse current limiting on ISENSE2, and synchronized start-up triggered only after PFC output reaches regulation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Oscillator Frequency | 80–120 kHz; set by RT/CT; enables EMI optimization and transformer size reduction in universal-input designs. |
| VCC UVLO Threshold | 16.5 V turn-on / 10 V turn-off; supports bootstrap bias supply operation and ensures reliable startup under brownout conditions. |
| PFC Gate Driver (GT1) | 95% max duty cycle, 5–12 Ω pull-up/pull-down; drives MOSFET gates directly with <50 ns rise/fall times into 1 nF load. |
| PWM Gate Driver (GT2) | 50% max duty cycle clamp, 5–12 Ω pull-up/pull-down; prevents transformer saturation in forward/isolated topologies. |
| Voltage Reference (VREF) | 7.5 V ±15 mV over –40°C to 85°C; powers external circuitry and sets PKLMT threshold scaling with <10 mV line/load regulation. |
| Zero-Power Detection | 0.175–0.500 V threshold on VAOUT; disables outputs when PFC output collapses, preventing unregulated secondary-stage operation. |
| Second-Stage UVLO2 Hysteresis | 3.0 V; allows PWM stage to remain active down to 50% of nominal bulk voltage-critical for holdup time extension. |
Pinout & Package
UCC28502DWTRG4 is housed in a 20-pin SOIC (DW) package with exposed thermal pad, rated for –40°C to 85°C operation. Pin assignments are fully defined per TI SLUS419C Rev. November 2001.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GT1 | PFC gate driver output | Drives boost switch MOSFET; supports >93% duty cycle and fast switching with integrated totem-pole driver. |
| GT2 | DC-DC gate driver output | Drives forward/LLC secondary switch; internally clamped to ≤50% duty cycle for safe transformer reset. |
| IAC | AC line current sense input | Current-input pin feeding analog multiplier; enables low-distortion RMS feedforward without high-voltage dividers. |
| VFF | RMS feedforward voltage node | Generated by mirroring IAC through external RC filter; scales multiplier gain to maintain constant input power. |
| VAOUT | PFC voltage amplifier output | Regulates boost output voltage; clamped to ~5.5 V to prevent overshoot; used for zero-power detection. |
| VERR | Secondary-side error signal input | Accepts optocoupler-fed error voltage; internal 4.5 V clamp enforces ≤50% GT2 duty cycle for reset assurance. |
| SS2 | PWM soft-start control | Charges external capacitor during startup; discharges rapidly on fault to disable PWM stage cleanly. |
| OVP/ENBL | PFC overvoltage & enable control | Window comparator: disables PFC if boost exceeds +6.67%, disables both stages if pulled below 1.9 V. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated dual-stage control | Eliminates need for separate PFC and PWM controllers-reduces BOM count, layout area, and inter-stage timing complexity. |
| VFF-based feedforward | Uses IAC mirror + single-pole RC filter to generate line-voltage-proportional VFF, avoiding high-voltage resistors and trimming. |
| Synchronized modulation scheme | Leading-edge PFC + trailing-edge PWM minimizes overlap conduction, reducing RMS ripple current in bulk output capacitor by up to 40%. |
| Programmable soft-start (SS2) | Internal current source charges external cap; enables controlled ramp-up of PWM duty cycle, preventing inrush stress on transformer and rectifiers. |
| Wide UVLO2 hysteresis (3.0 V) | Allows second-stage operation down to 50% of nominal bulk voltage-extending holdup time and improving brownout resilience. |
Applications
| Industrial AC-DC Power Supplies | Telecom Rectifier Modules |
|---|---|
Use Scenario: 85–265 VRMS input, 12 V/10 A output with 16 ms holdup requirement. IC Role / Device Role / Timing Role: Dual-stage controller managing boost PFC followed by isolated forward converter; coordinates sequencing via VAOUT monitoring and SS2 ramp. Use Value: Enables single-chip compliance with IEC 61000-3-2 Class A harmonic limits while supporting extended holdup via 50% UVLO2 threshold. |
Use Scenario: -48 V telecom system with hot-swap capability and strict efficiency targets (>85% at full load). IC Role / Device Role / Timing Role: Regulates boost stage for stable 385 V bus, then controls forward converter with opto-coupled feedback on VERR. Use Value: Reduces output capacitor ripple current by synchronized edge alignment, lowering ESR heating and extending electrolytic life. |
| Server Front-End Power | Medical Equipment Power Modules |
Use Scenario: Universal-input 3.3/5/12 V multi-rail supply with safety isolation and low audible noise. IC Role / Device Role / Timing Role: Controls continuous-conduction-mode (CCM) boost PFC and transformer-isolated DC-DC; uses VFF feedforward for tight line regulation. Use Value: Achieves <0.99 PF across full input range without trimming, simplifying certification and reducing upstream breaker sizing. |
Use Scenario: UL/IEC 60601-1 compliant 24 V/5 A power module requiring low leakage, high reliability, and fault-safe shutdown. IC Role / Device Role / Timing Role: Monitors VAOUT for zero-power condition and asserts OVP/ENBL to disable both stages during output collapse. Use Value: Prevents unregulated secondary operation during PFC failure-meeting essential safety requirement for patient-connected systems. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-stage PFC+PWM controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| UCC28502DWR | Same die, tape-and-reel vs. cut-tape; identical electrical specs, thermal performance, and pinout. | No functional difference; selected for automated SMT assembly requiring 2000-unit reels. | Choose UCC28502DWR for volume production; UCC28502DWTRG4 is functionally identical but marked per TI's G4 green standard. |
| UCC38502DWTR | Commercial temperature grade (0°C to 70°C); same UVLO2 hysteresis (3.0 V) and pinout, but narrower ambient range. | Not qualified for industrial (-40°C to 85°C) operation; unsuitable for outdoor or factory-floor deployments. | Select UCC28502DWTRG4 when extended temperature support and RoHS-compliant packaging (G4) are required. |
Compared with UCC28502DWR and UCC38502DWTR, the UCC28502DWTRG4 provides identical dual-stage control functionality and industrial-grade temperature rating, while adding TI's green (lead-free, halogen-free) packaging compliance-making it the preferred choice for new industrial and medical designs requiring long-term availability and environmental certification.
Availability
UCC28502DWTRG4 is available at Aetrix Electronics and suitable for industrial AC-DC power supplies, telecom rectifier modules, and medical equipment power modules requiring stable component supply, long lifecycle support, and RoHS-compliant packaging.
Supply support for UCC28502DWTRG4 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 and embedded processing technologies, with decades of expertise in power management IC design and manufacturing.
The UCC2850x product line was engineered specifically for cost-sensitive, high-efficiency AC-DC conversion systems requiring integrated PFC and isolated DC-DC control in a single package-targeting industrial, telecom, and server power applications.
FAQ
What is the primary function of the UCC28502DWTRG4 in a power supply design?
The UCC28502DWTRG4 serves as a dual-stage controller that manages both active power factor correction (PFC) and downstream DC-DC conversion in a single IC. It implements average-current-mode control for the boost PFC stage and peak-current-mode control for the isolated PWM stage-enabling compact, high-efficiency universal-input AC-DC power supplies. Its architecture eliminates the need for separate controllers and reduces system-level timing coordination complexity.
How does the UCC28502DWTRG4 achieve near-unity power factor?
The UCC28502DWTRG4 achieves near-unity power factor by shaping the AC input current waveform to match the AC line voltage using average-current-mode control. It employs an analog multiplier that divides sensed line current (IAC) by the square of the RMS feedforward voltage (VFF), generated via an internal IAC mirror and external RC filter. This closed-loop technique maintains sinusoidal input current across 85–265 VRMS inputs without high-voltage components.
What is the purpose of the VFF pin on the UCC28502DWTRG4?
The VFF pin on the UCC28502DWTRG4 provides the RMS line voltage feedforward signal used by the internal analog multiplier to maintain constant input power across varying AC line voltages. It is generated by mirroring half the IAC current into an external RC filter, producing a voltage proportional to line RMS-typically 1.4 V at low line and ~4.7 V at high line. This eliminates the need for high-voltage resistive dividers and improves line regulation accuracy.
Does the UCC28502DWTRG4 support isolated DC-DC topologies like forward or flyback?
Yes, the UCC28502DWTRG4 supports isolated DC-DC topologies including forward and flyback. Its VERR pin accepts an externally generated error signal-typically delivered via optocoupler from the secondary side-enabling precise regulation of isolated outputs. The IC enforces a 50% maximum duty cycle on GT2 to ensure safe transformer reset, making it especially well-suited for forward converters.
What is the significance of the 3.0 V UVLO2 hysteresis in the UCC28502DWTRG4?
The 3.0 V UVLO2 hysteresis in the UCC28502DWTRG4 allows the downstream DC-DC stage to remain operational even when the PFC output drops to 50% of its nominal voltage-significantly extending holdup time during AC line sags or interruptions. This wider hysteresis distinguishes UCC28502DWTRG4 from narrow-hysteresis variants (e.g., UCC28501) and is critical for applications requiring robust brownout resilience, such as industrial motor drives and telecom rectifiers.
UCC28502DWTRG4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 20-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Mode:
- Average Current
- Frequency - Switching:
- 100kHz
- Current - Startup:
- 150 µA
- Voltage - Supply:
- 9.7V ~ 18V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SOIC
UCC28502DWTRG4 FAQ
1.How can I place an order for UCC28502DWTRG4 through Aetrix?
Please submit a Request for Quotation (RFQ) for UCC28502DWTRG4 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 UCC28502DWTRG4 reliable?
The price and inventory of UCC28502DWTRG4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for UCC28502DWTRG4 is usually 5 days.
3.What payment methods are accepted for UCC28502DWTRG4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for UCC28502DWTRG4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for UCC28502DWTRG4?
UCC28502DWTRG4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your UCC28502DWTRG4 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 UCC28502DWTRG4?
For technical support, including UCC28502DWTRG4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your UCC28502DWTRG4 requirements.
6.How does Aetrix verify that UCC28502DWTRG4 is sourced from the original manufacturer or authorized distributors?
All UCC28502DWTRG4 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 UCC28502DWTRG4 meets industry standards.
7.What is the process for return or replacement of UCC28502DWTRG4?
All UCC28502DWTRG4 units undergo pre-shipment inspection (PSI). If there is an issue with UCC28502DWTRG4, 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 UCC28502DWTRG4 part is unused and in its original packaging.
Return procedure for UCC28502DWTRG4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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