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Texas Instruments UCC38050P
- Part No.:
- UCC38050P
- Manufacturer:
- Texas Instruments
- Category:
- PFC (Power Factor Correction)
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
UCC38050P.pdf
- Description:
- IC PFC CTL TRANSITION 200KZ 8DIP
- Quantity:
- Payment:
- Shipping:
Inventory:817
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Product details
Overview
UCC38050 from Texas Instruments is a transition-mode (boundary-conduction mode) power factor correction (PFC) controller for low-to-medium power boost preregulators, featuring 2.5 V internal reference voltage, ±750-mA peak gate drive current, 6.3 V UVLO hysteresis, and zero-power detect for light-load OVP prevention - used in electronic ballasts and single-stage PFC flyback converters.
For engineers reviewing the UCC38050 datasheet, UCC38050 pinout, UCC38050 application, or UCC38050 equivalent, this page delivers verified technical context, real-world design meaning of key specs, validated pin functions, confirmed alternative parts with functional distinctions, and supply-chain support details specific to UCC38050's PDIP-8 package and industrial temperature range (0°C to 70°C).
Technical Context
The UCC38050 implements self-oscillating transition-mode control: turn-on is triggered by zero-current detection (ZCD pin), turn-off by current-sense comparator threshold (CS pin ≤1.7 V), with multiplier output proportional to VMULTIN × (VCOMP −2.5 V). Its transconductance error amplifier (gM = 90 µS typ.) drives loop compensation via COMP pin with dynamic input range 2.5–3.8 V.
UVLO has 15.8 V turn-on / 9.7 V turn-off (6.3 V hysteresis), enabling fast start-up with small VCC capacitor; zero-power detect activates when VCOMP falls below 2.3 V, latching DRV low during no-load to prevent overvoltage; OVP triggers at VO_SNS ≥ VREF + 0.19 V (≈2.69 V) with 200 mV hysteresis.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC UVLO Turn-on | 15.8 V - enables reliable start-up with smaller bulk capacitor and faster VCC charge time |
| Internal VREF | 2.50 V ±0.04 V - ensures tight output voltage regulation (±1.6%) across temperature |
| Gate Drive Current | ±750 mA peak - directly drives medium-size MOSFETs without external buffer in <300 W designs |
| Transconductance gM | 90 µS typical - defines loop gain stability margin and compensates for wide line/load variations |
| ZCD Input Threshold | 1.7 V rising edge - sets precise zero-current detection timing to maintain boundary conduction |
| CS Max Threshold | 1.7 V - limits peak switch current to protect MOSFET and inductor under overload |
| OVP Threshold | VREF + 0.19 V (≈2.69 V) - second-level protection clamping output at ≤7.5% above nominal |
Pinout & Package
UCC38050 is housed in an 8-pin PDIP package (6.35 mm × 9.81 mm), rated for 0°C to 70°C operation, with through-hole mounting and lead (Pb)-free finish.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VO_SNS (Pin 1) | Inverting input to transconductance amplifier & OVP comparator | Senses regulated output via resistor divider; pulls DRV low if open-loop or pre-charge detected |
| COMP (Pin 2) | Error amplifier output & multiplier input | Drives loop compensation network; voltage range 2.5–3.8 V defines current command scaling |
| MULTIN (Pin 3) | Multiplier input for rectified line voltage sensing | Accepts 0–2.5 V signal; includes 75 mV offset to reduce zero-crossing THD distortion |
| CS (Pin 4) | Current sense input to PWM comparator | Detects MOSFET peak current; clamped internally at 1.7 V to terminate switching cycle |
| ZCD (Pin 5) | Zero-current detector input | Monitors auxiliary winding voltage; triggers turn-on when inductor current reaches zero |
| GND (Pin 6) | Signal and power ground reference | Return path for all analog and digital circuitry; requires shortest possible PCB trace to bypass caps |
| DRV (Pin 7) | High-current totem-pole gate driver output | Delivers ±750 mA peak to drive N-channel MOSFET; rise/fall times <75 ns with 1 nF load |
| VCC (Pin 8) | Supply input with UVLO monitoring | Operates from 12–18 V; internal clamp limits to 20 V; wide 6.3 V hysteresis eases start-up |
Key Features
| Feature | Design Value |
|---|---|
| Transition-mode PFC control | Self-oscillating CRM operation eliminates need for external clock; reduces EMI and rectifier reverse-recovery loss |
| Slew-rate enhanced error amplifier | Boosts sink/source current >1 mA during over/under-voltage transients - cuts start-up time and improves line-step response |
| Zero-power detect | Latches DRV off when VCOMP < 2.3 V - prevents output overvoltage during no-load or standby without auxiliary circuitry |
| Integrated OVP and enable protection | OVP triggers at VO_SNS ≥ 2.69 V; enable disables DRV if VO_SNS < 0.67 V - protects against open feedback or brownout |
| Industry-pin-compatible upgrade | Direct replacement for legacy PFC controllers (e.g., UC3852 family) with improved gM, tighter VREF, and lower IQ |
Applications
| Electronic Ballasts | Single-Stage PFC Flyback |
|---|---|
Use Scenario: High-efficiency fluorescent lamp drivers requiring IEC 61000-3-2 Class C compliance. IC Role / Device Role / Timing Role: Transition-mode PFC controller regulating boost stage output to 400 V DC while shaping input current waveform. Use Value: Eliminates need for separate PFC + DC-DC stages; achieves >0.98 PF and <10% THD with minimal magnetics. |
Use Scenario: Compact AC/DC adapters for LED lighting and motor drives where space and BOM count are critical. IC Role / Device Role / Timing Role: Integrated PFC+flyback controller managing both input current shaping and isolated output regulation in one topology. Use Value: Reduces component count by 30% vs two-stage designs; leverages UCC38050's zero-power detect to avoid output overvoltage during dimming. |
| Desktop PC Power Supplies | AC Adapter Front-Ends |
Use Scenario: 150–250 W ATX PSUs needing Class D harmonic compliance and high efficiency at light loads. IC Role / Device Role / Timing Role: Boost PFC controller operating in boundary conduction mode to minimize conduction loss and EMI filter size. Use Value: Achieves >92% efficiency at 20% load using UCC38050's low 4 mA operating current and 75 µA start-up current. |
Use Scenario: Universal-input 12–24 V adapters for consumer electronics requiring robust no-load behavior. IC Role / Device Role / Timing Role: Primary-side PFC controller enforcing IEC 1000-3-2 limits while coordinating with downstream PWM via enable pin. Use Value: Uses UCC38050's 6.3 V UVLO hysteresis to ensure stable start-up across wide input voltage range without auxiliary bias winding. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar PFC controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| UCC38051 | Lower UVLO turn-on (12.5 V) and reduced gM source current (300 µA); same pinout and package | Better suited for two-stage converters where downstream PWM controls PFC enable timing | Select UCC38051 when system requires coordinated start-up with secondary controller; UCC38050 preferred for standalone PFC stages |
| UC3854BDW | Fixed-frequency CCM controller; higher IQ (10 mA), no zero-power detect, SOIC-16 package | Used in higher-power (>300 W), fixed-frequency PFC designs with stricter EMI requirements | Choose UC3854BDW only if CCM operation, higher power, or synchronous rectification is required - not drop-in compatible |
Compared with UCC38051, UCC38050 offers faster start-up and stronger transient response due to higher gM source current and wider UVLO hysteresis; compared with UC3854BDW, UCC38050 reduces component count and EMI filtering cost via transition-mode operation but targets lower power ranges.
Availability
UCC38050 is available at Aetrix Electronics and suitable for electronic ballasts, AC adapter front-ends, and desktop PC power supplies requiring stable component supply, long-term lifecycle support, and traceable sourcing for industrial and commercial production.
Supply support for UCC38050 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 delivering analog and embedded processing solutions, with over 50 years of power management innovation and broad distribution infrastructure.
The UCC38050 belongs to TI's Transition-Mode PFC Controller product line, designed specifically for cost-sensitive, low-to-medium power AC/DC systems requiring IEC 61000-3-2 compliance without complex control loops or external timing components.
FAQ
What is the operating temperature range for the UCC38050?
The UCC38050 is specified for operation from 0°C to 70°C ambient temperature. This industrial-grade range supports reliable performance in enclosed power supplies such as electronic ballasts and desktop PSUs. The device's thermal resistance (RθJA = 55.6°C/W in PDIP-8) allows adequate power dissipation without forced airflow in typical layouts. Derating is recommended above 60°C ambient for continuous full-load operation.
How does the zero-power detect function work in the UCC38050?
The UCC38050's zero-power detect monitors the COMP pin voltage and activates when it falls below 2.3 V - indicating near-zero load conditions. This latches the DRV output low, halting switching to prevent output overvoltage during no-load or standby. Unlike external OVP circuits, this feature requires no additional components and operates independently of VO_SNS feedback integrity, making it ideal for energy-efficient lighting drivers.
Can the UCC38050 be used in continuous conduction mode (CCM)?
No - the UCC38050 is specifically designed for transition-mode (boundary-conduction mode) operation only. Its control architecture relies on zero-current detection (ZCD pin) to trigger switching, and lacks the ramp compensation or fixed-frequency oscillator needed for stable CCM. Attempting CCM operation will result in erratic frequency behavior and potential instability. For CCM, TI recommends the UCC28070 or UC3854 series.
What is the purpose of the 75 mV offset in the MULTIN path of the UCC38050?
The 75 mV offset applied to the MULTIN signal improves zero-crossing distortion performance by shifting the effective multiplier input baseline. This reduces harmonic content near the AC line zero-crossing point, directly lowering total harmonic distortion (THD) and helping meet IEC 61000-3-2 Class C limits for lighting equipment. The offset is internal and requires no external component adjustment.
Does the UCC38050 support direct connection to a microcontroller enable signal?
Yes - the UCC38050's VO_SNS pin serves dual-purpose as both output voltage sense and enable input. Pulling VO_SNS below 0.67 V (enable threshold) forces DRV low and disables switching. This allows clean, logic-level enable/disable control from a microcontroller GPIO without level-shifting, provided the MCU can sink sufficient current to pull VO_SNS to ground through a series resistor.
UCC38050P Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-DIP (0.300", 7.62mm)
- Packaging:
- Bulk
- Product Status:
- Active
- Mode:
- Discontinuous (Transition)
- Frequency - Switching:
- 200kHz
- Current - Startup:
- 75 µA
- Voltage - Supply:
- 15.4V ~ 18V
- Operating Temperature:
- 0°C ~ 70°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 8-PDIP
UCC38050P FAQ
1.How can I place an order for UCC38050P through Aetrix?
Please submit a Request for Quotation (RFQ) for UCC38050P 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 UCC38050P reliable?
The price and inventory of UCC38050P are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for UCC38050P is usually 5 days.
3.What payment methods are accepted for UCC38050P?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for UCC38050P transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for UCC38050P?
UCC38050P orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your UCC38050P 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 UCC38050P?
For technical support, including UCC38050P datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your UCC38050P requirements.
6.How does Aetrix verify that UCC38050P is sourced from the original manufacturer or authorized distributors?
All UCC38050P 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 UCC38050P meets industry standards.
7.What is the process for return or replacement of UCC38050P?
All UCC38050P units undergo pre-shipment inspection (PSI). If there is an issue with UCC38050P, 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 UCC38050P part is unused and in its original packaging.
Return procedure for UCC38050P:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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