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 ONOFF 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.

    L6599主要特性:

■ 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

    L6599应用:

■ LCD and PDP TV

■ Desktop PC, entry-level server

■ Telecom SMPS

■ AC-DC adapter, open frame SMPS

图1.L6599方框图

图2.采用L6599和L6563 90W适配器电路图

    STEVAL-ISA018V1评估板

    This user manual describes a high efficiency solution for industrial power supplies with a continuous output power of 150 W and peak power up to 240 W. It takes advantage of the resonant approach to minimize switching losses, resulting in higher than 90% efficiency. The topology is based on half-bridge and operated in a resonant fashion by means of a resonant LC tank, driven by the L6599 dedicated controller.

    The board provides one regulated output, VO=24 V with IO=6 A, and an overload capability of up to IO=10 A. Output voltage and current are controlled by the TSM1011 constant voltage and constant current controller, providing square output regulation, while the overload is managed by thermal protection (PTC) on the output rectifiers.


图3. STEVAL-ISA018V1外形图

    STEVAL-ISA018V1主要指标:


图4. STEVAL-ISA018V1电路图

    STEVAL-ISA018V1材料清单: