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High-voltage resonant controller
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The L6599 is a double-ended controller specific for the resonant half-bridge topology. It provides 50 % complementary duty cycle: the high-side switch and the low-side switch are driven ON\OFF 180° out-of-phase for exactly the same time.

Output voltage regulation is obtained by modulating the operating frequency. A fixed deadtime inserted between the turn-OFF of one switch and the turn-ON of the other one guarantees soft-switching and enables high-frequency operation.

To drive the high-side switch with the bootstrap approach, the IC incorporates a high-voltage floating structure able to withstand more than 600 V with a synchronous-driven high-voltage DMOS that replaces the external fast-recovery bootstrap diode.

The IC enables the designer to set the operating frequency range of the converter by means of an externally programmable oscillator.

At start-up, to prevent uncontrolled inrush current, the switching frequency starts from a programmable maximum value and progressively decays until it reaches the steady-state value determined by the control loop. This frequency shift is non linear to minimize output voltage overshoots; its duration is programmable as well.

The IC can be forced to enter a controlled burst-mode operation at light load, so as to keep converter's input consumption to a minimum.

IC's functions include a not-latched active-low disable input with current hysteresis useful for power sequencing or for brownout protection, a current sense input for OCP with frequency shift and delayed shutdown with automatic restart.

A higher level OCP latches off the IC if the first-level protection is not sufficient to control the primary current. Their combination offers complete protection against overload and short circuits. An additional latched disable input (DIS) allows easy implementation of OTP and/or OVP.

An interface with the PFC controller is provided that enables to switch off the pre-regulator during fault conditions, such as OCP shutdown and DIS high, or during burst-mode operation.

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Errata Sheet
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Key Features

  • 50 % duty cycle, variable frequency control of resonant half-bridge
  • High-accuracy oscillator
  • Up to 500 kHz operating frequency
  • Two-level OCP: frequency-shift and latched shutdown
  • Interface with PFC controller
  • Latched disable input
  • Burst-mode operation at light load
  • Input for power-ON/OFF sequencing or brownout protection
  • Non-linear soft-start for monotonic output voltage rise
  • 600 V-rail compatible high-side gate driver with integrated bootstrap diode and high dV/dt immunity
  • -300/800 mA high-side and low-side gate drivers with UVLO pull-down
  • DIP-16, SO-16N packages

Circuit Diagram

Design Resources


Technical Documentation

Product Specifications

Description Version Size
DS4739: High-voltage resonant controller
3.1 633 KB

Application Notes

Description Version Size
AN2450: LLC resonant half-bridge converter design guideline
6.0 747 KB
AN2644: An introduction to LLC resonant half-bridge converter
2.0 1,314 KB

Related Tools and Software

Related Tools and Software

Part Number Description
STEVAL-ISC002V1 Resonant LCC 90 W notebook power adapter based on the L6599 and STP9NK50ZF

Publications and Collaterals

Conference Paper

Description Version Size
1.0.0 418 KB

Sample & Buy

Part Number Marketing StatusPackagePacking TypeAutomotive GradeOrder From STUnit Price (US$)*
@ 1000
Distributor AvailabilityRoHS Compliance GradeDownload
Material Declaration**
L6599DNRNDSO-16Tube_-1.475Distributor reported inventory date: 2015-05-28
Distributor NameRegionStockMin. order
Farnell Element14Order NowEUROPE851
Ecopack2 (**)PDF
L6599DTRNRNDSO-16Tape And Reel_-1.475Distributor reported inventory date: 2015-05-28
Distributor NameRegionStockMin. order
ARROWOrder NowEUROPE150000
Ecopack2 (**)PDF
L6599NNRNDPDIP 16Tube_-1.475Distributor reported inventory date: 2015-05-28
Distributor NameRegionStockMin. order
ARROWOrder NowAMERICA3661000
Farnell Element14Order NowEUROPE431

(*) Suggested Resale Price per unit (USD) for BUDGETARY USE ONLY. For quotes, prices in local currency, please contact your local ST Sales Office or our Distributors
(**) The Material Declaration forms available on may be generic documents based on the most commonly used package within a package family. For this reason, they may not be 100% accurate for a specific device. Please contact our sales support for information on specific devices.
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