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Enhanced high-voltage resonant controller
  • active Active

The L6699 is a double-ended controller specific to series-resonant half bridge topology. Both LLC and LCC configurations are supported. It provides symmetrical 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. The deadtime inserted between the turn-off of one switch and the turn-on of the other one is automatically adjusted to best fit the transition times of the half bridge midpoint. 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 user to set the operating frequency range of the converter by means of a high-accuracy externally programmable oscillator.

At startup, in addition to the traditional frequency-shift soft-start (the switching frequency starts from a preset maximum value and then decays as far as the steady-state value determined by the control loop), a proprietary circuit controls the half bridge to prevent hard-switching from occurring in the initial cycles because of the unbalance in the V·s applied to the transformer.

At light load the IC can be forced to enter a controlled burst-mode operation that keeps the converter input consumption as low as possible.

IC protection functions include a current sense input for OCP with frequency shift and delayed shutdown with automatic restart. Fast shutdown with automatic restart occurs if this first-level protection cannot control the primary current. Additionally, the IC prevents the converter from working in or too close to the capacitive mode, to guarantee soft-switching. A latched disable input (DIS) can be used to implement OTP and/or OVP. The combination of these protection features offers the highest degree of safety.

Other functions include a not-latched active-low disable input with current hysteresis, useful for power sequencing or for brownout protection, and an interface with the PFC controller that enables the switching-off of the pre-regulator during fault conditions or during burst-mode operation.

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Errata Sheet
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Key Features

  • Symmetrical duty cycle, variable frequency control of resonant half bridge
  • Self-adjusting adaptive deadtime
  • High-accuracy oscillator
  • 2-level OCP: frequency-shift and immediate shutdown
  • Interface with PFC controller
  • Anti-capacitive-mode protection
  • Burst-mode operation at light load
  • Input for brownout protection or power-on/off sequencing
  • “Safe-start” procedure prevents hard switching at startup
  • 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
  • SO16N package

Design Resources


Technical Documentation

Product Specifications

Description Version Size
DS8908: Enhanced high voltage resonant controller
2.0 955 KB

Application Notes

Description Version Size
AN4026: 19 V - 90 W adapter with PFC for laptop computers using the L6563H and L6699
1.2 989 KB
AN4027: 12 V - 150 W resonant converter with synchronous rectification using the L6563H, L6699 and SRK2000A
3.0 2,884 KB
AN4599: STEVAL-ISA132V1 24 V 300 W peak power resonant converter
3.0 904 KB
AN4677: 12 V - 150 W resonant converter with synchronous rectification based on L6563H, L6699 and SRK2001
1.0 3,182 KB
AN4720: Half bridge resonant LLC converters and primary side MOSFET selection
1.0 1,436 KB

Design Notes & Tips

Description Version Size
DT0009: Speed up development of the L6699 with the L6599A and flexible PCB layout
1.0 262 KB

HW Model & CAD Libraries

HW Model & CAD Libraries

Description Version Size
L6699 ORCAD macromodel
94 KB
L6699 SIMPLIS MAROTTA encrypted
194 KB

Presentations & Training Material


Description Version Size
L6699: Enhanced high-voltage resonant controller
1.0 332 KB

Related Tools and Software

Related Tools and Software

Part Number Description
STEVAL-ISA143V1 12 V - 150 W resonant converter with synchronous rectification using the L6563H, L6699 and SRK2000
STEVAL-ISA138V1 19 V - 90 W adapter with PFC for laptop computers using the L6563H and L6699
EVL6699-90WADP 19V - 90W Adapter with PFC for Laptop computers using the L6563H and L6699
STEVAL-ISA132V1 300 W peak power (170 W continuous power) LLC resonant converter based on L6699, STB13N60M2 and STPS20M80CG
STEVAL-ISA170V1 12 V - 150 W resonant converter with synchronous rectification based on L6563H, L6699 and SRK2001
EVL400W-ADP/ATX 12V - 400W SMPS for Adapter, Desktop and AIO using L4984D, L6699 and SRK2000A

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**
L6699DActiveSO-16Tube_-1.475Distributor reported inventory date: 2015-09-01
Distributor NameRegionStockMin. order
Farnell Element14Order NowEUROPE1291
L6699DTRActiveSO-16Tape And Reel_Free Samples1.475Distributor reported inventory date: 2015-09-01
Distributor NameRegionStockMin. order
ARROWOrder NowAMERICA50002500
ARROWOrder NowEUROPE100000
Farnell Element14Order NowEUROPE15751

(*) 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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