l6599atn STMicroelectronics, l6599atn Datasheet - Page 3

• Manufacturer Part Number: l6599atn
• Description: Improved High-voltage Resonant Controller
• Manufacturer: STMicroelectronics

L6599AT
1
Device description
The L6599AT is a temperature-extended version of the L6599A. It is a double-ended
controller specifically designed for the series-resonant half-bridge topology. It provides a
50% complementary duty cycle: the high-side switch and the low-side switch are driven
ON/OFF at 180° out-of-phase for exactly the same time interval. Output voltage regulation is
obtained by modulating the operating frequency. A fixed dead-time inserted between the
turn-off of one switch and the turn-on of the other guarantees soft-switching and enables
high-frequency operation.
To drive the high-side switch using the bootstrap approach, the IC incorporates a high-
voltage floating structure capable of withstanding 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.
At light load the IC may enter a controlled burst-mode operation that keeps the converter
input consumption to a minimum.
The device’s functions include a not-latched active-low disable input with current hysteresis
suitable 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 the switching off of the pre-
regulator during fault conditions, such as OCP shutdown and DIS high, or during burst-
mode operation.
Doc ID 15534 Rev 1
Device description
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