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STMicroelectronics L6566ATR
- Part No.:
- L6566ATR
- Manufacturer:
- STMicroelectronics
- Category:
- AC DC Converters, Offline Switches
- Package:
- 16-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
L6566ATR.pdf
- Description:
- IC OFFLINE SWITCH FLYBACK 16SO
- Quantity:
- Payment:
- Shipping:
Inventory:2,434
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Product details
Overview
L6566ATR from STMicroelectronics is a multi-mode current-mode PWM controller IC designed for high-performance offline flyback converters with PFC front-end stages. It supports selectable fixed-frequency (FF) or quasi-resonant (QR) operation, features 700 V high-voltage startup, adaptive UVLO, pulse-by-pulse OCP with hiccup-mode protection, and integrated 5 V reference output. It targets >150 W power supplies in LCD TVs and notebook adapters.
For engineers reviewing the L6566ATR datasheet, L6566ATR pinout, L6566ATR application, or L6566ATR equivalent, key selection criteria include QR/FF mode flexibility, transformer saturation detection, PFC controller interface (Vcc_PFC), line feedforward for constant power regulation, and latched/auto-restart OVP/OCP configuration options.
Technical Context
The L6566ATR implements dual-mode control logic: in FF mode, it operates as a standard current-mode controller with 70% minimum max duty cycle and slope compensation; in QR mode, it uses ZCD-triggered MOSFET turn-on synchronized to transformer demagnetization, enabling valley switching and potential ZVS. The MODE/SC pin selects mode via connection to VREF.
Its protection architecture includes two-level OCP: first-level (CS pin, 0.450 V threshold) enables delayed shutdown with soft-start capacitor timing; second-level (CS pin, 1.5 V threshold) detects transformer saturation or secondary diode short-circuit and latches off. Brownout (AC_OK < 0.45 V) and OVP (ZCD > 5 V) are non-latched, while DIS > 4.5 V triggers latched disable.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Operating Modes | Fixed-frequency (FF) or quasi-resonant (QR), selected via MODE/SC pin connection to VREF |
| Startup Voltage | 700 V HV startup on HVS pin - directly connects to rectified mains without external resistor network |
| Gate Drive | ±800 mA totem-pole output - drives MOSFET/IGBT gates directly with active pull-down during UVLO |
| OCP Thresholds | 0.450 V (pulse-by-pulse overload) and 1.5 V (saturation/failure detection) on CS pin |
| Voltage Reference | 5 V ±2% on VREF pin - supplies external circuitry with ≤5 mA, internally monitored for fault latching |
| Line Feedforward | VFF input (0–3 V range) scales OCP threshold inversely with input voltage - maintains constant power across universal AC input |
| Brownout Threshold | AC_OK pin trips at <0.45 V - disables gate drive, opens Vcc_PFC, clears latches, and halts switching |
Pinout & Package
Package: SO16N (16-pin small outline, 1.27 mm pitch, body width 3.9 mm, JEDEC MS-012AC).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| HVS (Pin 1) | High-voltage startup input | 700 V-rated terminal - charges Vcc capacitor from rectified mains; internal 1 mA current source shuts down above UVLO |
| N.C. (Pin 2) | No internal connection | PCB clearance provision - required for creepage/clearance compliance in high-voltage designs |
| GND (Pin 3) | Signal and gate-drive return | Common ground for all analog blocks and totem-pole driver - must be star-connected to minimize noise coupling |
| GD (Pin 4) | Gate driver output | ±800 mA push-pull output - actively pulls gate low during UVLO to prevent spurious turn-on |
| Vcc (Pin 5) | Main supply rail | Self-supplied after startup - UVLO thresholds adapt dynamically (5.7 V turn-on, ~5 V restart) to counter parasitic drop |
| Vcc_PFC (Pin 6) | PFC controller supply output | Switched 12–15 V output - enabled during normal operation, disabled during light load/brownout/latch to reduce system standby loss |
| CS (Pin 7) | Current sense comparator input | 150 ns leading-edge blanking - compares sensed MOSFET current against 0.450 V (OCP) or 1.5 V (saturation) |
| DIS (Pin 8) | Latched disable input | Trips at >4.5 V - forces latch-off until Vcc falls below UVLO; used for external OTP with NTC |
| COMP (Pin 9) | Error amplifier output / loop control | 2.5–5 V dynamic range - voltage < threshold enables burst-mode; bottom-clamped at ~2 V |
| VREF (Pin 10) | Internal voltage reference | 5 V ±2%, ≤5 mA sourcing - monitored by auxiliary reference; fault causes immediate latch-off |
| ZCD (Pin 11) | Zero-current detection / OVP input | QR trigger input - negative edge initiates MOSFET turn-on; >5 V triggers OVP shutdown (latch/auto-restart configurable) |
| MODE/SC (Pin 12) | Mode selection / slope compensation | Connected to VREF → QR mode; else FF mode - also provides ramp for slope compensation when tied to CS |
| OSC (Pin 13) | Oscillator frequency setting | 1 V reference - external R to GND sets oscillator frequency (FF: actual fSW; QR: max fSW) |
| SS (Pin 14) | Soft-start / fault timing | Charges external capacitor - controls duty ramp-up at startup and delays OCP shutdown timing |
| VFF (Pin 15) | Line voltage feedforward | 0–3 V input - linearly scales OCP threshold to maintain constant power across 85–265 VAC |
| AC_OK (Pin 16) | Brownout detection | 0.45 V threshold - non-latched shutdown with hysteresis (15 µA current sink below threshold) |
Key Features
| Feature | Design Value |
|---|---|
| Multi-mode operation selection | Hardware-selectable FF or QR via single MODE/SC pin tie - eliminates firmware or configuration overhead |
| Transformer saturation detection | Dual-threshold CS comparator (0.450 V + 1.5 V) - distinguishes overload from core saturation/failure without external circuitry |
| Adaptive UVLO | Dynamic turn-on threshold (5.7 V nominal) that lowers under light load - prevents false shutdown due to winding leakage-induced Vcc droop |
| PFC controller interface | Vcc_PFC pin delivers regulated supply to PFC IC - automatically disabled at light load to meet EU CoC Tier 2 standby requirements |
| Controlled burst-mode entry | COMP pin voltage threshold activation - enables precise, noise-immune transition to low-power operation without oscillation |
Applications
| LED Backlight Power Supply | 150 W Notebook Adapter |
|---|---|
|
Use Scenario: High-efficiency, low-noise flyback converter powering LED strings in LCD TV backlight units with PFC pre-regulator. IC Role / Device Role / Timing Role: Primary-side QR controller synchronizing MOSFET turn-on to transformer demagnetization zero-crossing for ZVS and EMI reduction. Use Value: Valley skipping at medium load preserves ZVS behavior; line feedforward ensures constant LED current across universal AC input range. |
Use Scenario: Dual-stage AC-DC adapter delivering 19 V/8 A with EN61000-3-2 compliance and <300 mW no-load consumption. IC Role / Device Role / Timing Role: FF-mode controller managing primary-side regulation, with Vcc_PFC disabling PFC stage during standby to cut auxiliary losses. Use Value: Adaptive UVLO prevents dropout during brownout dips; 700 V HVS eliminates startup resistor, improving reliability and thermal margin. |
| Set-Top Box Auxiliary PSU | PDP Display Logic Supply |
|
Use Scenario: Compact 24 W auxiliary power supply for digital broadcast receivers requiring tight hold-up time and low standby power. IC Role / Device Role / Timing Role: Burst-mode controller activated via COMP pin voltage - reduces switching frequency and gate drive loss at <10% load. Use Value: Integrated 5 V reference powers optocoupler bias and microcontroller reset circuit - eliminates discrete LDO and saves board space. |
Use Scenario: 45 W logic supply for plasma display panels with stringent OVP response (<10 µs) and thermal derating requirements. IC Role / Device Role / Timing Role: Dual-OCP protected controller using CS pin's 1.5 V saturation threshold to detect failed secondary rectifiers before catastrophic failure. Use Value: Latched DIS input interfaces with NTC on heatsink - provides hardware-based OTP with guaranteed shutdown independent of software state. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar multi-mode flyback controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ICE2QS03G | Fixed-frequency only; no QR capability; 650 V startup; no Vcc_PFC output | Lacks PFC coordination and valley-switching efficiency - suitable only for cost-sensitive FF-only designs | Select when QR operation and PFC interface are unnecessary and BOM cost is prioritized over efficiency |
| UCC28064D | Integrated PFC + QR flyback combo controller; 600 V startup; no separate Vcc_PFC pin | Single-chip PFC+PWM reduces component count but lacks independent PFC disable control for ultra-low standby | Select for simplified two-stage design where PFC cannot be independently shut down, accepting higher light-load loss |
Compared with ICE2QS03G and UCC28064D, the L6566ATR uniquely combines QR/FF mode flexibility, dedicated Vcc_PFC control for PFC stage disable, and dual-threshold OCP - making it optimal for high-efficiency, standards-compliant systems requiring precise loss management across full load range.
Availability
L6566ATR is available at Aetrix Electronics and suitable for LCD TV power supplies, notebook adapters, and set-top box auxiliary PSUs requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for L6566ATR 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
STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing analog, MCU, power, and sensor solutions for industrial, automotive, and consumer markets.
The L6566A belongs to ST's high-voltage AC-DC controller product line, engineered specifically for energy-efficient, two-stage offline SMPS complying with EN61000-3-2 and CoC Tier 2 standards.
FAQ
What is the function of the MODE/SC pin, and how does it affect operation?
The MODE/SC pin selects between fixed-frequency (FF) and quasi-resonant (QR) modes: tying it to VREF enables QR operation, where MOSFET turn-on is triggered by ZCD zero-current detection; leaving it unconnected enables FF mode, where OSC sets the exact switching frequency and slope compensation is applied. In FF mode, the pin also outputs a synchronized ramp for slope compensation when connected to CS via a resistor.
How does the L6566ATR implement adaptive UVLO, and why is it critical?
Adaptive UVLO dynamically lowers the Vcc turn-off threshold under light load conditions to compensate for reduced self-supply voltage caused by transformer leakage inductance and winding resistance. This prevents false shutdown during brownout dips or low-load operation, ensuring reliable restart and stable burst-mode transitions without external hysteresis components.
Can the Vcc_PFC pin supply a PFC controller during startup, and what happens if unused?
Yes - Vcc_PFC is internally connected to Vcc via a controlled switch that closes at startup and remains active until light load, brownout, or latch conditions occur. If unused, the pin must be left floating; grounding it will disrupt PFC supply sequencing and may cause startup failure or erratic PFC behavior.
What protection functions are latched versus auto-restart, and how are they configured?
OVP (ZCD > 5 V), OCP second-level (CS > 1.5 V), and DIS > 4.5 V are latched; brownout (AC_OK < 0.45 V) and first-level OCP (CS > 0.450 V) are auto-restart. Latch mode is selected externally via resistor networks on ZCD and SS pins per Table 7 in the datasheet - no internal register configuration is required.
L6566ATR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- -
- Package/Case:
- 16-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Output Isolation:
- Isolated
- Internal Switch(s):
- No
- Voltage - Breakdown:
- -
- Topology:
- Flyback
- Voltage - Start Up:
- 14 V
- Voltage - Supply (Vcc/Vdd):
- 8V ~ 23V
- Duty Cycle:
- 70%
- Frequency - Switching:
- 100kHz
- Power (Watts):
- -
- Fault Protection:
- Current Limiting, Over Load
- Control Features:
- Frequency Control, Soft Start
- Operating Temperature:
- -40°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Supplier Device Package:
- 16-SO
- Mounting Type:
- Surface Mount
L6566ATR FAQ
1.How can I place an order for L6566ATR through Aetrix?
Please submit a Request for Quotation (RFQ) for L6566ATR 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 L6566ATR reliable?
The price and inventory of L6566ATR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for L6566ATR is usually 5 days.
3.What payment methods are accepted for L6566ATR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for L6566ATR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for L6566ATR?
L6566ATR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your L6566ATR 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 L6566ATR?
For technical support, including L6566ATR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your L6566ATR requirements.
6.How does Aetrix verify that L6566ATR is sourced from the original manufacturer or authorized distributors?
All L6566ATR 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 L6566ATR meets industry standards.
7.What is the process for return or replacement of L6566ATR?
All L6566ATR units undergo pre-shipment inspection (PSI). If there is an issue with L6566ATR, 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 L6566ATR part is unused and in its original packaging.
Return procedure for L6566ATR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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