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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > AC DC Converters, Offline Switches

STMicroelectronics L6591TR

Name: L6591TR
Brand: STMicroelectronics
SKU: L6591TR
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: L6591TR

Manufacturer:: STMicroelectronics

Category:: AC DC Converters, Offline Switches

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

Datasheet:: L6591TR.pdf

Description:: IC OFFLINE SW HALF-BRIDGE 16SO

Quantity:: RFQ Add To RFQ list

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Product details

Overview

L6591TR from STMicroelectronics is a double-ended PWM controller IC designed specifically for zero-voltage-switching (ZVS) half-bridge topologies in high-efficiency AC-DC power supplies. It delivers complementary gate drive with programmable deadtime, integrates a 600 V-rail-compatible high-side driver with synchronous bootstrap diode, supports up to 500 kHz switching frequency, and features adaptive UVLO, pulse-by-pulse OCP, and transformer saturation detection - enabling robust operation in telecom and server SMPS.

For engineers reviewing the L6591TR datasheet, L6591TR pinout, L6591TR application, or L6591TR equivalent, this device is selected for ZVS half-bridge control where soft-switching integrity, high-voltage startup autonomy, PFC interface capability, and hiccup-mode overcurrent protection are critical design requirements.

Technical Context

The L6591TR implements a T-flip-flop–limited PWM architecture that enforces ≤46% maximum duty cycle and halves oscillator frequency to set switching frequency (e.g., 180 kHz oscillator → 90 kHz converter). Its high-side driver uses an integrated synchronous bootstrap DMOS (R_DS(on) = 125 Ω) referenced to FGND, eliminating external fast-recovery diodes while maintaining >50 V/ns dV/dt immunity.

Adaptive UVLO dynamically adjusts turn-on/turn-off thresholds (V_ccOn = 13–15 V, V_ccOff = 8.2–11.3 V) based on COMP voltage level to stabilize light-load operation. The LINE pin provides brownout detection (1.25 V threshold, 15 µA hysteresis current), and the PFC_STOP pin delivers open-drain control synchronized to burst-mode transitions.

Key Specifications

Parameter	Value and Actual Design Meaning
Operating Frequency	Up to 500 kHz switching (oscillator up to 192 kHz); enables compact magnetics in high-power SMPS
High-Side Driver Voltage Rating	600 V rail-compatible with FGND-referenced operation; supports direct connection to half-bridge high-side switch
VREF Accuracy	5 V ±4% (4.8–5.2 V); supplies stable reference for external circuits up to 5 mA
Pulse-by-Pulse OCP Threshold	0.8 V on ISEN pin; triggers immediate high-side shutdown per cycle to prevent MOSFET overstress
Deadtime Control	Programmable via OSC capacitor (e.g., 330 pF → 1.0 µs deadtime); ensures ZVS by preventing shoot-through
Startup Current	0.55–1 mA HVSTART current; charges VCC autonomously from rectified mains without auxiliary winding
Burst Mode Trigger	COMP < 1.75 V (falling edge); reduces no-load consumption while maintaining regulation via gated PWM

Pinout & Package

Package: SO16N (SOIC-16 narrow, 150 mil width), RoHS-compliant, ECOPACK® certified.

Pin/Terminal	Circuit Role	Design Meaning
1 LINE	Brownout / sequencing input	1.25 V threshold with 15 µA hysteresis; shuts down IC below threshold for safe power-on or line fault response
2 DIS	Latched disable input	4.5 V threshold; forces permanent shutdown until VCC drops below UVLO - used for OTP/OVP latch
3 ISEN	Current sense comparator input	Three-level protection: 0.8 V (pulse-by-pulse OCP), 1.5 V (hiccup mode), 200 ns blanking window
4 SS	Soft-start timing node	20 µA internal charge current ramps external capacitor; controls duty-cycle ramp and OCP delay timing
5 OSC	Oscillator timing node	Resistor-to-VREF + capacitor-to-GND sets oscillator frequency and deadtime (T_dead ∝ C_T)
6 VREF	5 V reference output	±4% accuracy, 5 mA drive capability; powers optocoupler bias or error amplifier references
7 COMP	PWM control loop input	0.4 mA typical sink current; 1.75 V falling-edge trigger initiates burst mode at light load
8 PFC_STOP	Open-drain PFC disable output	Drives low when COMP < 1.75 V; synchronizes PFC shutdown during burst intervals to meet energy standards
9 VCC	Low-side supply & logic rail	11.3–22 V operating range; adaptive UVLO thresholds shift with COMP voltage to stabilize light-load VCC
10 LVG	Low-side gate driver output	0.3 A source / 0.8 A sink peak; drives lower MOSFET gate directly with fast rise/fall (<80/40 ns)
11 GND	Signal & low-side return	Common return for bias, COMP filter, and LVG sink current; must be isolated from high-dI/dt paths
12 N.C.	High-voltage spacer	No internal connection; maintains creepage distance between HV and LV pin groups per safety standards
13 FGND	High-side floating ground	Return path for HVG current; layout-critical node - must minimize inductance to avoid false triggering
14 HVG	High-side gate driver output	0.3 A source / 0.8 A sink peak; referenced to FGND; requires pull-down resistor to FGND during UVLO
15 BOOT	Bootstrap supply input	Internally fed by synchronous bootstrap DMOS; replaces external diode and enables reliable high-side drive
16 HVSTART	High-voltage startup input	700 V max rating; 0.8 mA internal current source charges VCC capacitor directly from rectified AC bus

Key Features

Feature	Design Value
Integrated synchronous bootstrap DMOS	Replaces external fast-recovery diode; eliminates reverse recovery loss and improves reliability in high-dV/dt environments
Adaptive UVLO with dual thresholds	Adjusts V_ccOn/V_ccOff based on COMP voltage to maintain stable operation across wide load range including burst mode
Transformer saturation detection	1.5 V hiccup-mode OCP threshold on ISEN pin; latches off IC upon sustained overcurrent indicating core saturation or secondary short
PFC controller interface	Open-drain PFC_STOP output synchronized to COMP voltage transitions; enables coordinated light-load PFC shutdown
Digital leading-edge blanking	200 ns fixed blanking window after HVG rising edge; rejects switching noise spikes on current-sense path

Applications

Telecom SMPS

Desktop PC Power Supply

Use Scenario: 1–3 kW telecom rectifiers requiring high efficiency (>90%) and ZVS operation across full load range.

IC Role / Device Role / Timing Role: Primary-side ZVS half-bridge PWM controller with adaptive deadtime and high-voltage startup.

Use Value: Enables >94% efficiency at 100 kHz due to soft-switching enforcement and low-loss synchronous bootstrap drive.

Use Scenario: ATX main power stage in mid-range desktop PCs with active PFC front-end.

IC Role / Device Role / Timing Role: Secondary-side half-bridge controller coordinating with PFC via PFC_STOP signal during burst mode.

Use Value: Reduces no-load power to <0.5 W by gating both PFC and PWM stages synchronously under light load.

Entry-Level Server PSU

High-Power AC-DC Adapter

Use Scenario: 80 PLUS Bronze-certified 500–800 W server PSUs operating at 90–100 kHz.

IC Role / Device Role / Timing Role: Complementary PWM generator with programmable deadtime and transformer saturation protection.

Use Value: Prevents catastrophic failure during overload by latching off on 1.5 V ISEN threshold - detects saturation before MOSFET destruction.

Use Scenario: Industrial-grade 300–600 W laptop charger with universal AC input (90–264 VAC).

IC Role / Device Role / Timing Role: High-voltage startup-enabled controller eliminating auxiliary winding and reducing BOM count.

Use Value: Achieves <300 mW no-load consumption using HVSTART + burst mode + adaptive UVLO co-optimization.

Equivalent & Alternatives

The following parts are listed as comparable options for similar ZVS half-bridge PWM controller applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
UCC2895DW	Fixed 50% duty cycle, no adaptive UVLO, requires external bootstrap diode, higher quiescent current (5 mA vs. 3.5 mA)	Designed for phase-shifted full-bridge; lacks LINE sensing and PFC_STOP interface	Choose only if phase-shift topology is required and PFC coordination is handled externally
ICE2PCS01	Integrated PFC + LLC combo controller; no high-side gate driver; 650 V startup but no synchronous bootstrap	Single-chip PFC+resonant solution; not suitable for discrete half-bridge with independent PFC stage	Select only for cost-sensitive single-stage designs where ZVS half-bridge is not the target topology

Compared with UCC2895DW and ICE2PCS01, the L6591TR uniquely combines ZVS half-bridge PWM control, integrated synchronous bootstrap, PFC interface, and adaptive UVLO - making it the only option among the three that supports high-efficiency two-stage telecom/server SMPS with autonomous high-voltage startup and transformer saturation protection.

Availability

L6591TR is available at Aetrix Electronics and suitable for telecom rectifiers, desktop PC power supplies, and entry-level server PSUs requiring stable component supply, long-lifecycle support, and compliance with ECOPACK® environmental standards.

Supply support for L6591TR 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, specializing in power management, analog, microcontrollers, and automotive ICs.

The L6591TR belongs to ST's high-voltage PWM controller product line, engineered specifically for soft-switched resonant and ZVS half-bridge topologies in high-efficiency AC-DC conversion systems.

FAQ

What is the purpose of the LINE pin on the L6591TR?

The LINE pin serves dual functions: power-on sequencing in PFC-based systems and brownout protection. It monitors the rectified AC bus via a resistor divider; when voltage falls below 1.25 V, the IC shuts down and discharges the soft-start capacitor. An internal 15 µA hysteresis current ensures noise-immune transition, and the pin can be tied to VCC with a 220–330 kΩ resistor if unused.

How does the L6591TR achieve zero-voltage switching in a half-bridge?

The L6591TR enforces ZVS through programmable deadtime insertion between high-side and low-side gate drive transitions, set by the OSC capacitor value. Its complementary PWM outputs ensure non-overlapping drive signals, while the integrated synchronous bootstrap DMOS sustains high-side gate voltage during deadtime - allowing resonant tank voltage to swing to zero before turn-on.

Can the L6591TR operate without an auxiliary winding?

Yes. The HVSTART pin provides onboard high-voltage startup: a 0.8 mA internal current source charges the VCC capacitor directly from the rectified mains, eliminating need for auxiliary winding or external startup circuitry. The HVSTART pin withstands up to 700 V, and the internal generator restarts VCC charging when VCC drops below 4.4–5.6 V after UVLO or latch events.

What protection features does the L6591TR provide against transformer saturation?

The L6591TR detects transformer saturation via its ISEN pin's third-level comparator, which triggers hiccup-mode OCP at 1.4–1.65 V. This latches off the IC, reducing consumption to ~0.35 mA until power recycle. Unlike pulse-by-pulse OCP (0.8 V), this level responds to sustained overcurrent - a definitive indicator of core saturation or secondary diode short - preventing thermal runaway.

L6591TR 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:: Half-Bridge

Voltage - Start Up:: 14 V

Voltage - Supply (Vcc/Vdd):: 8.7V ~ 22V

Duty Cycle:: 50%

Frequency - Switching:: Up to 500kHz

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

L6591TR FAQ

1.How can I place an order for L6591TR through Aetrix?

Please submit a Request for Quotation (RFQ) for L6591TR 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 L6591TR reliable?

The price and inventory of L6591TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for L6591TR is usually 5 days.

3.What payment methods are accepted for L6591TR?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for L6591TR transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for L6591TR?

L6591TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your L6591TR 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 L6591TR?

For technical support, including L6591TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your L6591TR requirements.

6.How does Aetrix verify that L6591TR is sourced from the original manufacturer or authorized distributors?

All L6591TR 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 L6591TR meets industry standards.

7.What is the process for return or replacement of L6591TR?

All L6591TR units undergo pre-shipment inspection (PSI). If there is an issue with L6591TR, 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 L6591TR part is unused and in its original packaging.

Return procedure for L6591TR:

1.Submit a request within 90 days.

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

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