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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > Power Supply Controllers, Monitors

Texas Instruments UCC256404DDBT

Name: UCC256404DDBT
Brand: Texas Instruments
SKU: UCC256404DDBT
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: UCC256404DDBT

Manufacturer:: Texas Instruments

Category:: Power Supply Controllers, Monitors

Package:: 16-SOIC (0.154", 3.90mm Width), 14 Leads

Datasheet:: UCC256404DDBT.pdf

Description:: HALF BRIDGE CONT WITH HV DRIVER

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Product details

Overview

UCC256404DDBT from Texas Instruments is a high-integration LLC resonant controller with integrated 0.6A/1.2A high-voltage gate driver, hybrid hysteretic control (HHC), adaptive dead-time adjustment, and active X-capacitor discharge. It delivers ultra-low audible noise in burst mode and meets DoE Level VI and EU CoC Tier-2 standby power standards for TV, projector, and medical AC-DC power supplies.

For engineers reviewing the UCC256404DDBT datasheet, UCC256404DDBT pinout, UCC256404DDBT application, or UCC256404DDBT equivalent, key selection considerations include its 16-pin SOIC (DDB) package, programmable burst soft-on/off thresholds, 12.7–13.45V regulated RVCC output, 100ns minimum dead time, and integrated HV startup JFET with 8.9–13.5mA X-cap discharge current.

Technical Context

The UCC256404DDBT implements Hybrid Hysteretic Control (HHC) using resonant capacitor voltage (VCR) to directly regulate input current, enabling first-order-like transient response and fast exit from burst mode. Its slew-rate-based adaptive dead-time logic monitors HS node voltage (dVHS/dt = ±50 V/ns) to dynamically adjust timing between HO and LO outputs.

It integrates a high-voltage startup JFET (IHVHigh = 7.6–13.5 mA at VHV = 20V) and active X-capacitor discharge circuit (IXCAPDischarge = 8.9–13.5 mA), distinguishing it from UCC256402 (no X-cap discharge) and UCC256403 (no HV startup). Burst mode uses programmable BMTL/BMTH ratios via BW pin resistor options and includes soft-on/off ramping to suppress acoustic noise.

Key Specifications

Parameter	Value and Actual Design Meaning
VCC operating range	13–26 V: Supports direct bias winding supply without auxiliary LDO; UVLO rising threshold 7.85–8.70 V ensures reliable restart after brownout.
RVCC output	12.7–13.45 V @ 100 mA: Powers external PFC controller (e.g., UCC28056) and synchronous rectifier (e.g., UCC24624) with stable regulation.
Gate drive capability	HO/LO: 0.6 A source / 1.2 A sink; enables direct drive of N-channel MOSFETs in half-bridge LLC stage without external drivers.
Burst mode quiescent current	650–950 µA: Enables sub-30 mW no-load power in compliant AC-DC adapters meeting EU CoC Tier-2.
X-cap discharge current	8.9–13.5 mA: Actively discharges line-filter X-capacitors post-unplug per IEC 62368-1 safety requirements.
Adaptive dead-time range	100 ns – 1.1 µs (ZCS undetected) or 150 µs (ZCS detected): Prevents shoot-through while maintaining ZVS across load and line variations.
Thermal shutdown	125–145 °C with 10 °C hysteresis: Protects against sustained overload or poor heatsinking in enclosed power supplies.

Pinout & Package

UCC256404DDBT is housed in a 16-pin SOIC package (DDB), 9.9 mm × 3.9 mm, with pins 2 and 13 omitted for creepage/clearance compliance. The package supports standard SOIC reflow profiles and provides 74.7 °C/W junction-to-ambient thermal resistance.

Pin/Terminal	Circuit Role	Design Meaning
HV	High-voltage startup input	Connects to AC line via resistor divider; powers internal JFET (7.6–13.5 mA) and enables X-cap discharge detection (Vzero-crossing = 8–11 V).
VCC	Main supply input	Accepts 13–26 V bias winding supply; includes UVLO (7.85–8.70 V) and restart threshold (9.35–9.95 V).
RVCC	Regulated 13 V output	Supplies external PFC controller and gate drivers; delivers up to 100 mA with tight regulation (±0.35 V).
FB	Feedback current input	Sinks 73–91 µA; controls LLC input power level via optocoupler current; internal 90–110 kΩ pull-down sets DC operating point.
BLK	Bulk voltage sense	Detects AC line presence and initiates LLC switching when VBLKStart = 0.98–1.02 V (UCC256404-specific low-threshold variant).
ISNS	Resonant current sense	Monitors differentiated VCR signal; triggers OCP1 (3.9–4.1 V) for immediate shutdown or OCP2/OCP3 (0.57–0.46 V) with 2–50 ms delay for robust overload handling.
VCR	Resonant capacitor voltage sense	Primary input for Hybrid Hysteretic Control; enables direct input current regulation and best-in-class transient response.
HO / LO	High-side / low-side gate outputs	Drive N-MOSFET gates with 0.6 A source / 1.2 A sink; HO referenced to HB, LO referenced to GND; rise/fall times ≤50 ns (1 nF load).
HS	High-side floating ground	Returns high-side gate current; used with HB to form bootstrap supply; supports dVHS/dt detection for adaptive dead-time.
BW	Bias winding OVP & burst programming	Provides output overvoltage protection (VBWOVPos = 3.86–4.12 V) and programs BMTL/BMTH ratio via resistor options (KBMTL/BMTH1–7).
LL/SS	Soft-start & burst threshold	Capacitor-connected pin sets soft-start duration; resistor divider defines initial voltage and programs burst exit threshold (VLLVolPrgm = 3.5 V).
GND	Signal ground reference	Common return for all analog and digital circuits; must be low-impedance connection to minimize noise coupling into FB/ISNS/VCR paths.

Key Features

Feature	Design Value
Hybrid Hysteretic Control (HHC)	Uses VCR as primary control variable to achieve near-first-order system behavior, delivering <10 µs load transient recovery and eliminating need for complex loop compensation.
Programmable burst soft-on/off	Configurable via BW pin resistor network; ramps resonant current gradually during burst packet edges to reduce mechanical vibration and audible noise below 20 kHz.
Integrated X-capacitor discharge	Active discharge path (8.9–13.5 mA) triggered post-unplug; satisfies IEC 62368-1 touch-current safety limits without external circuitry.
Robust ZCS avoidance	Detects zero-current switching via ISNS polarity hysteresis (16–44 mV); overrides feedback and forces frequency ramp-up until non-capacitive operation resumes.
Three-level overcurrent protection	OCP1 (instant trip), OCP2 (2 ms delay), OCP3 (50 ms delay) provide graded fault response-preventing nuisance trips while ensuring transformer/MOSFET survival under short-circuit conditions.

Applications

TV Power Supply	Enterprise Projector
Use Scenario: 150–300 W primary-side LLC converter powering LED backlight and main logic board in 4K/8K flat-panel TVs. IC Role / Device Role / Timing Role: Primary LLC controller managing resonant tank frequency, gate timing, and burst-mode transitions during channel change or standby. Use Value: Achieves <30 mW no-load power and eliminates audible coil whine during dark scenes or menu navigation via soft-on/off burst modulation.	Use Scenario: 200–500 W sealed-chassis AC-DC supply for laser phosphor or DLP projectors requiring high reliability and low EMI. IC Role / Device Role / Timing Role: Core timing and protection controller coordinating PFC (UCC28056) and LLC stages; manages thermal derating and OCP sequencing. Use Value: Integrated X-cap discharge ensures safe touch voltage <2 s after unplugging-critical for wall-mounted or ceiling-installed units per IEC 62368-1.
Medical AC-DC Adapter	Gaming Console PSU
Use Scenario: 65–120 W Class II isolated adapter powering patient-monitoring equipment with strict leakage current and efficiency mandates. IC Role / Device Role / Timing Role: Standby-optimized LLC controller enforcing DoE Level VI and EU CoC Tier-2 compliance while supporting dynamic load steps from idle to full CPU/GPU activity. Use Value: 650–950 µA burst-mode ICCSleep enables <25 mW no-load consumption; opto-coupler low-power operation reduces feedback path losses.	Use Scenario: High-efficiency 300–600 W multi-rail PSU for next-gen gaming consoles with rapid load transients (0–100% in <100 µs) and thermal throttling. IC Role / Device Role / Timing Role: Fast-response LLC controller using HHC to maintain output regulation during GPU boost cycles; coordinates with UCC24624 SR controller. Use Value: <10 µs load transient recovery prevents brownout resets; adaptive dead-time maintains ZVS across 10:1 load range, improving efficiency at light loads.

TV Power Supply

Enterprise Projector

Use Scenario: 150–300 W primary-side LLC converter powering LED backlight and main logic board in 4K/8K flat-panel TVs.

IC Role / Device Role / Timing Role: Primary LLC controller managing resonant tank frequency, gate timing, and burst-mode transitions during channel change or standby.

Use Value: Achieves <30 mW no-load power and eliminates audible coil whine during dark scenes or menu navigation via soft-on/off burst modulation.

Use Scenario: 200–500 W sealed-chassis AC-DC supply for laser phosphor or DLP projectors requiring high reliability and low EMI.

IC Role / Device Role / Timing Role: Core timing and protection controller coordinating PFC (UCC28056) and LLC stages; manages thermal derating and OCP sequencing.

Use Value: Integrated X-cap discharge ensures safe touch voltage <2 s after unplugging-critical for wall-mounted or ceiling-installed units per IEC 62368-1.

Medical AC-DC Adapter

Gaming Console PSU

Use Scenario: 65–120 W Class II isolated adapter powering patient-monitoring equipment with strict leakage current and efficiency mandates.

IC Role / Device Role / Timing Role: Standby-optimized LLC controller enforcing DoE Level VI and EU CoC Tier-2 compliance while supporting dynamic load steps from idle to full CPU/GPU activity.

Use Value: 650–950 µA burst-mode ICCSleep enables <25 mW no-load consumption; opto-coupler low-power operation reduces feedback path losses.

Use Scenario: High-efficiency 300–600 W multi-rail PSU for next-gen gaming consoles with rapid load transients (0–100% in <100 µs) and thermal throttling.

IC Role / Device Role / Timing Role: Fast-response LLC controller using HHC to maintain output regulation during GPU boost cycles; coordinates with UCC24624 SR controller.

Use Value: <10 µs load transient recovery prevents brownout resets; adaptive dead-time maintains ZVS across 10:1 load range, improving efficiency at light loads.

Equivalent & Alternatives

The following parts are listed as comparable options for similar LLC resonant controller applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
UCC256402DDBT	Lacks active X-capacitor discharge; BLK start threshold higher (2.94–3.06 V vs. 0.98–1.02 V); no burst soft-on/off.	Suitable for cost-sensitive consumer adapters where X-cap discharge is not mandated and bulk voltage sensing uses higher threshold.	Select UCC256402DDBT only if X-cap discharge and low-threshold BLK operation are unnecessary; verify BLK divider design matches higher VBLKStart.
UCC256404ADDBT	Same package and pinout; differs in BW OVP fault response-latches off instead of restarting after OVP event.	Preferred for safety-critical systems requiring fail-safe shutdown on output overvoltage (e.g., medical, industrial) rather than auto-recovery.	Choose UCC256404ADDBT when deterministic latch-off behavior is required for OVP; confirm system-level fault-handling logic aligns with latched state.

Compared with UCC256402DDBT and UCC256404ADDBT, the UCC256404DDBT uniquely combines active X-cap discharge, low-threshold BLK sensing, and restart-mode BW OVP-making it optimal for high-compliance consumer and commercial power supplies needing both safety and auto-recovery.

Availability

UCC256404DDBT is available at Aetrix Electronics and suitable for TV power supplies, enterprise projectors, and medical AC-DC adapters requiring stable component supply, long-term lifecycle support, and certified safety features.

Supply support for UCC256404DDBT 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 ICs and high-reliability industrial solutions.

The UCC25640x family is designed specifically for high-efficiency, low-noise LLC resonant converters in AC-DC power supplies-targeting stringent global energy standards and acoustic performance requirements in consumer, medical, and professional AV equipment.

FAQ

What is the purpose of the HV pin on the UCC256404DDBT?

The HV pin on the UCC256404DDBT connects to the AC line via a resistor divider to enable high-voltage startup using an internal JFET (7.6–13.5 mA), eliminating the need for an auxiliary supply. It also serves as the input for active X-capacitor discharge, detecting zero-crossing events (Vzero-crossing = 8–11 V) to trigger discharge current (8.9–13.5 mA) after AC removal-ensuring compliance with IEC 62368-1 safety limits. This dual function is exclusive to UCC256404DDBT and UCC256402DDBT.

How does the UCC256404DDBT achieve ultra-low audible noise in standby mode?

The UCC256404DDBT achieves ultra-low audible noise through programmable burst mode with soft-on and soft-off periods: during each burst packet, the switching frequency ramps down at the beginning and ramps up at the end to gradually increase and decrease resonant current, minimizing mechanical vibration in magnetics and capacitors. Combined with low-quiescent-current operation (650–950 µA) and opto-coupler bias optimization, this enables silent standby in TV and projector power supplies meeting strict acoustic requirements.

What distinguishes the UCC256404DDBT from the UCC256403DDBT in terms of startup and protection?

The UCC256404DDBT integrates a high-voltage startup JFET and active X-capacitor discharge circuit, whereas the UCC256403DDBT requires an external bias supply for VCC and lacks both features. Additionally, UCC256404DDBT uses a lower BLK start threshold (0.98–1.02 V) versus UCC256403DDBT's 2.94–3.06 V, enabling earlier LLC activation from low-bulk conditions. These differences make UCC256404DDBT self-sufficient for full-range AC input operation without auxiliary circuitry.

Can the UCC256404DDBT be used with a UCC28056 PFC controller?

Yes, the UCC256404DDBT is explicitly designed to pair with the UCC28056 PFC controller, as confirmed in TI's official documentation. The UCC256404DDBT's RVCC pin (12.7–13.45 V regulated output) supplies the UCC28056's VDD, while shared ground and coordinated fault signaling (e.g., BLK, FB) enable seamless system-level protection. This combination forms a complete, minimal-component PFC + LLC solution meeting DoE Level VI and EU CoC Tier-2 standards.

What is the significance of the LL/SS pin functionality in the UCC256404DDBT?

The LL/SS pin on the UCC256404DDBT serves dual functions: during startup, it sets soft-start duration via an external capacitor (Css = 4.7–470 nF); after startup, it programs the burst mode exit threshold (BMTH) using a resistor divider. Its voltage (VLLVolPrgm = 3.5 V) determines when the controller exits burst mode, enabling precise tuning of light-load efficiency versus transient response. This pin replaces separate soft-start and burst configuration pins found in older controllers, reducing external component count.

UCC256404DDBT Specifications

Product attributes: Attribute value

Manufacturer:: Texas Instruments

Series:: -

Package/Case:: 16-SOIC (0.154", 3.90mm Width), 14 Leads

Packaging:: Tape & Reel (TR)

Product Status:: Active

Programmable:: Not Verified

Applications:: Resonant Converter Controller

Voltage - Input:: 600V

Voltage - Supply:: 13V ~ 26V

Current - Supply:: 2.2 mA

Operating Temperature:: -40°C ~ 125°C (TA)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 14-SOIC

UCC256404DDBT FAQ

1.How can I place an order for UCC256404DDBT through Aetrix?

Please submit a Request for Quotation (RFQ) for UCC256404DDBT 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 UCC256404DDBT reliable?

The price and inventory of UCC256404DDBT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for UCC256404DDBT is usually 5 days.

3.What payment methods are accepted for UCC256404DDBT?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for UCC256404DDBT transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for UCC256404DDBT?

UCC256404DDBT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your UCC256404DDBT 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 UCC256404DDBT?

For technical support, including UCC256404DDBT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your UCC256404DDBT requirements.

6.How does Aetrix verify that UCC256404DDBT is sourced from the original manufacturer or authorized distributors?

All UCC256404DDBT 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 UCC256404DDBT meets industry standards.

7.What is the process for return or replacement of UCC256404DDBT?

All UCC256404DDBT units undergo pre-shipment inspection (PSI). If there is an issue with UCC256404DDBT, 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 UCC256404DDBT part is unused and in its original packaging.

Return procedure for UCC256404DDBT:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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