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Texas Instruments UCC28514N
- Part No.:
- UCC28514N
- Manufacturer:
- Texas Instruments
- Category:
- PFC (Power Factor Correction)
- Package:
- 20-DIP (0.300", 7.62mm)
- Datasheet:
-
UCC28514N.pdf
- Description:
- IC PFC CTR AV CURR 200KHZ 20DIP
- Quantity:
- Payment:
- Shipping:
Inventory:4,674
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Product details
Overview
UCC28514N from Texas Instruments is a dual-stage combination controller integrating average-current-mode PFC and peak-current-mode PWM control in a single 20-pin PDIP package. It delivers 2-A source / 3-A sink gate drive for both stages, supports 1:2 PFC:PWM frequency ratio (e.g., 100 kHz PFC / 200 kHz PWM), features programmable maximum duty cycle clamp (70–80%), and enables leading-edge PFC + trailing-edge PWM modulation to minimize boost capacitor ripple current in offline AC-DC power supplies.
For engineers reviewing the UCC28514N datasheet, UCC28514N pinout, UCC28514N application, or UCC28514N equivalent, this device is selected for high-efficiency, IEC 61000-3-2-compliant front-end designs requiring synchronized dual-loop control, precise power limiting, zero-power detect, and robust gate drive for MOSFETs in boost PFC + flyback/forward topologies.
Technical Context
The UCC28514N implements a three-input analog multiplier with input voltage feedforward (VFF) and transconductance voltage amplifier (VAOUT) to generate a highly linear line-current reference for continuous conduction mode (CCM) PFC. Its PFC section uses average-current-mode control with zero-power detection below 0.33 V on VAOUT and accurate power limiting via IMOUT × VFF calculation.
The PWM stage operates at twice the PFC frequency (1:2 ratio), employs peak-current-mode control with slope compensation via CT_BUFF, and includes programmable soft-start (SS2), UVLO2 with 5.3 V turn-off threshold and 1.45 V hysteresis, and a clamped maximum duty cycle set by D_MAX voltage (70–80% range).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| PFC:PWM Frequency Ratio | 1:2 - PWM stage runs at double PFC frequency (e.g., 200 kHz PWM / 100 kHz PFC), reducing output capacitor ripple and enabling tighter transient response coordination. |
| Gate Drive Capability | 2-A source / 3-A sink per output (GT1, GT2) - drives standard MOSFET gates directly without external buffers in medium-power (<300 W) applications. |
| Maximum Duty Cycle Clamp | 70–80% (programmable via D_MAX pin) - prevents transformer saturation in two-transistor forward or flyback PWM stages. |
| UVLO2 Turn-Off Threshold | 5.30 V - ensures PWM stage remains active until PFC output drops to ~71% of nominal, supporting hold-up time during line dropout. |
| Zero Power Detect Threshold | 0.33 V on VAOUT (falling edge) - disables PFC gate drive when output load falls near zero, eliminating no-load consumption. |
| Reference Voltage Accuracy | 7.50 V ±1.5% over temperature - provides stable bias for feedback dividers, OVP, and internal comparators across –40°C to +105°C. |
| Rise/Fall Time (1 nF load) | 16 ns rise / 7 ns fall - enables fast switching transitions while maintaining noise immunity in high-frequency PFC/PWM operation. |
Pinout & Package
UCC28514N is housed in a 20-pin plastic dual in-line package (PDIP-N), with separate analog ground (GND) and power ground (PWRGND) pins for noise isolation. Thermal dissipation is rated at 1 W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GT1 (12) | PFC gate driver output | 2-A source / 3-A sink totem pole - directly drives boost MOSFET gate; disabled during UVLO or VREF fault. |
| GT2 (10) | PWM gate driver output | Identical drive strength to GT1 - controls PWM switch (e.g., flyback primary MOSFET); enabled only after PFC reaches 90% target. |
| VSENSE (3) | PFC voltage error amplifier inverting input | Feedback node for PFC output regulation; also feeds OVP, ENABLE, and UVLO2 comparators - enables integrated protection functions. |
| VAOUT (1) | PFC transconductance amplifier output | Regulates PFC output voltage; sources/sinks up to 30 µA linearly, up to 3.3 mA during slew enhancement; <0.33 V triggers zero-power shutdown. |
| IAC (18) | Multiplier line-voltage current input | Accepts scaled rectified AC line current (≤500 µA); enables input voltage feedforward for near-unity power factor across universal input range. |
| VFF (19) | Voltage feedforward input | Sources IAC/2 current - forms RC-filtered feedforward signal that linearizes multiplier gain and improves load transient response. |
| CT_BUFF (5) | Buffered PWM oscillator ramp | 4-V amplitude buffered ramp - connects directly to ISENSE2 via resistor for slope compensation in peak-current-mode PWM control. |
| D_MAX (4) | PWM max duty cycle control | Analog input (0.09–0.90 V) sets 70–80% duty clamp - prevents core saturation in forward/flyback transformers under overload or startup. |
| SS2 (13) | PWM soft-start timing | Capacitor-to-ground sets PWM ramp duration - internal 10.5 µA current charges SS2 to 3 V, controlling GT2 duty ramp from 0% to clamped maximum. |
| PKLMT (14) | PFC peak current limit threshold | Voltage input referenced to 0 V - sets overcurrent trip point for boost inductor current; used with resistor divider from VREF and sense resistor. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated PFC + PWM synchronization | Enables leading-edge PFC + trailing-edge PWM modulation - reduces RMS ripple current in boost output capacitor by >30% vs. TEM/TEM schemes. |
| Programmable 1:2 frequency ratio | UCC28514N-specific architecture - allows higher PWM switching frequency for smaller magnetics while maintaining optimal PFC frequency for efficiency and EMI. |
| Transconductance voltage amplifier (gm) | 70–130 µS gain - provides fast voltage loop response with enhanced slew rate (3.3 mA peak) during line/load transients. |
| Zero-power detection | Hardware comparator monitoring VAOUT - shuts down PFC stage when output load approaches zero, eliminating standby power waste. |
| Accurate power limiting | Based on IMOUT × VFF multiplication - delivers consistent power limit across line and load variations without external circuitry. |
Applications
| Server Power Supply | Industrial AC-DC Adapter |
|---|---|
Use Scenario: 300–500 W telecom/server PSU with universal AC input (85–265 VAC) and strict IEC 61000-3-2 Class A harmonic limits. IC Role / Device Role / Timing Role: Primary controller for interleaved boost PFC + phase-shifted full-bridge PWM; manages sequencing, synchronization, and shared protection logic. Use Value: 1:2 frequency ratio enables 100 kHz PFC (efficiency-optimized) + 200 kHz PWM (size-optimized), reducing total solution size by 18% vs. discrete controllers. |
Use Scenario: 200 W industrial DIN-rail power supply operating in harsh environments (–40°C to +70°C ambient) with brownout resilience. IC Role / Device Role / Timing Role: Dual-loop controller for boost PFC + forward converter; implements UVLO2 hysteresis (1.45 V) and hold-up extension during line sag. Use Value: Zero-power detect and accurate power limiting reduce no-load consumption to <300 mW and prevent overcurrent damage during motor-start surges. |
| Medical Imaging Power Module | LED Driver Front-End |
Use Scenario: 400 W diagnostic imaging system power module requiring low EMI, high reliability, and EN 60601-1 compliance. IC Role / Device Role / Timing Role: Core timing and protection controller for PFC + LLC resonant PWM; leverages CT_BUFF ramp for precise slope compensation. Use Value: Leading-edge PFC + trailing-edge PWM minimizes boost capacitor ripple current, lowering capacitor temperature rise by 12°C and extending lifetime >50,000 hours. |
Use Scenario: High-bay LED driver with 300–480 VAC input and constant-current output, needing high PF (>0.98) and THD <10%. IC Role / Device Role / Timing Role: Average-current-mode PFC controller with input voltage feedforward (VFF) and linearized multiplier for distortion-free dimming compatibility. Use Value: Highly linear multiplier and VFF feedforward maintain >0.99 PF across 10–100% load, meeting ENERGY STAR SSL V2.1 requirements without additional calibration. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-stage PFC/PWM control applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| UCC28514DW | Same electrical specs and pinout; SOIC-20 package with 0.7 W power dissipation (vs. 1 W for N-package). | Preferred for automated SMT assembly and higher-density PCB layouts; lower thermal mass requires careful heatsinking in >250 W designs. | Select UCC28514DW for volume production with reflow capability; choose UCC28514N for prototyping, through-hole assembly, or higher ambient temperature operation. |
| UCC28070 | Dedicated CCM PFC controller only (no integrated PWM); 600 kHz max frequency; no 1:2 ratio or GT2 driver. | Requires external PWM controller (e.g., UC384x) - increases BOM count, layout complexity, and timing skew between stages. | Use UCC28070 only when PFC and PWM require independent optimization (e.g., variable-frequency PFC + resonant LLC), not for cost- or space-constrained dual-stage integration. |
Compared with UCC28514DW, the UCC28514N offers higher thermal margin in convection-cooled systems; compared with UCC28070, it eliminates inter-controller timing mismatch and reduces component count by 30%, but sacrifices independent loop tuning flexibility.
Availability
UCC28514N is available at Aetrix Electronics and suitable for server power supplies, industrial AC-DC adapters, medical imaging modules, and LED driver front-ends requiring stable component supply, long-lifecycle support, and guaranteed traceable sourcing.
Supply support for UCC28514N 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 architectures and high-reliability industrial design.
The UCC2851x family was engineered specifically for cost-sensitive, space-constrained offline AC-DC systems requiring IEC 61000-3-2 compliance - delivering integrated PFC+PWM control with synchronized modulation, programmable protection, and robust gate drive in a single chip.
FAQ
What is the key functional distinction of UCC28514N within the UCC2851x family?
The UCC28514N is uniquely configured for 1:2 PFC:PWM frequency ratio - its PWM stage operates at twice the PFC frequency (e.g., 200 kHz PWM / 100 kHz PFC). This distinguishes it from UCC28510–UCC28513 variants (1:1 ratio) and enables optimized trade-offs between PFC efficiency and PWM magnetic size. All timing, sequencing, and protection logic in UCC28514N is calibrated for this fixed ratio.
How does UCC28514N implement zero-power detection, and what is its impact on system efficiency?
UCC28514N monitors the VAOUT pin voltage: when VAOUT falls below 0.33 V (falling edge), the internal zero-power comparator disables GT1 gate drive. This halts PFC switching under near-zero load conditions, eliminating idle switching losses and reducing no-load input power to <300 mW - critical for meeting Energy Star and EU CoC Tier 2 standby requirements.
Can UCC28514N be used with discontinuous conduction mode (DCM) PFC topologies?
No - UCC28514N is designed exclusively for average-current-mode control in continuous conduction mode (CCM) PFC operation. Its multiplier architecture, current amplifier, and VAOUT slew enhancement assume CCM inductor current waveform. DCM operation would cause instability and inaccurate current regulation; TI specifies CCM as mandatory for all UCC2851x devices.
What is the role of the CT_BUFF pin in UCC28514N, and how is it used in practice?
The CT_BUFF pin outputs a buffered 4-V amplitude PWM oscillator ramp signal. In UCC28514N, it is connected via a single resistor to ISENSE2 to inject slope compensation into the PWM current-sense path - essential for stable peak-current-mode control in duty cycles >50%. This eliminates need for external ramp generators or complex compensation networks.
How does the D_MAX pin function, and what voltage range sets the PWM duty cycle limit in UCC28514N?
The D_MAX pin accepts a DC voltage (0.09 V to 0.90 V) to linearly program the maximum duty cycle at GT2 between 70% and 80%. For example, 0.50 V on D_MAX yields ~75% clamp. Voltages below 0.7 V force 0% duty cycle - enabling hard disable. This feature protects forward/flyback transformers from saturation during overload or startup faults in UCC28514N-based designs.
UCC28514N Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 20-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Obsolete
- 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:
- Through Hole
- Supplier Device Package:
- 20-PDIP
UCC28514N FAQ
1.How can I place an order for UCC28514N through Aetrix?
Please submit a Request for Quotation (RFQ) for UCC28514N 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 UCC28514N reliable?
The price and inventory of UCC28514N are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for UCC28514N is usually 5 days.
3.What payment methods are accepted for UCC28514N?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for UCC28514N transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for UCC28514N?
UCC28514N orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your UCC28514N 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 UCC28514N?
For technical support, including UCC28514N datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your UCC28514N requirements.
6.How does Aetrix verify that UCC28514N is sourced from the original manufacturer or authorized distributors?
All UCC28514N 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 UCC28514N meets industry standards.
7.What is the process for return or replacement of UCC28514N?
All UCC28514N units undergo pre-shipment inspection (PSI). If there is an issue with UCC28514N, 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 UCC28514N part is unused and in its original packaging.
Return procedure for UCC28514N:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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