ST company's Steval-ISA018V1 evaluation board is a 150W switching power solution, using high voltage resonant controller L6599, input voltage is 185V-265VAC or 85VAC, output voltage 24V +/- 2%, output power 150W, maximum power 240W, The security satisfies EN60950, EMI satisfies EN55014. This article describes the main characteristics of the L6599, block diagram, using the L6599 and L6563 90W adapter circuit diagrams and the main features, circuit diagrams and materials list.
The L6599 is a dual-end controller dedicated to a resonant half bridge topology. It provides a 50% complementary duty cycle: high-end switch and low-end switch are driven at all of the same time.
The output voltage regulation is obtained by adjusting the operating frequency. Insert a fixed dead time between the disconnection of one switch and the other switch, secure the soft switch and implement high frequency operation.
In order to drive the high-end switch by the bootstrap method, the IC integrates a high pressure floating structure capable of withstanding a voltage of 600 V, and using a synchronous drive high voltage DMOS instead of the exterior quickly restores the self-lifting diode.
The IC allows designers to set the operating frequency range of the converter via an external programmable oscillator.
At startup, in order to prevent uncontrolled surge current, the switching frequency starts from the programmable maximum, then gradually attenuate until the steady-state value determined by the control loop is reached. This frequency offset is non-linear to minimize overshoot of the output voltage. The duration is also programmable.
It can force the IC to enter the controlled burst mode operation under light load to keep the input consumption of the converter at the lowest level.
The ability of the IC includes a non-latch low-level non-latching low-level effective disable input, which can be used for power sorting or undervoltage protection; a current detection input of an OCP having a frequency shift function; a delay closure function with an automatic restart function.
If the first level protection is not sufficient to control the primary current, the higher level OCP will lock the IC. Their combination provides comprehensive protection against overload and short circuits. Additional latch disable input (DIS) allows OTP and / or OVP to be easily implemented.
The interface with the PFC controller provides the pre-regulator during fault conditions (e.g., OCP shutdown and DIS high) or burst mode operations.
L6599 Main features:
■ Duty cycle is 50%, converting the resonant half bridge
■ High-precision oscillator
■ Up to 500 kHz operating frequency
■ Two-level OCP: Move frequency and latching downtime
■ Interface with PFC controller
■ Blocking disable input
■ Emergency mode operation at light load
■ Input for power on / off or power-down protection
■ Nonlinear soft boot used in monotonic output voltage rises
■ Integrated 600 V-rail compatible with bootstrap diodes and high levels of high-end drive DV / DT immunization
■ -300/800 mA high-end and low-end gate drivers with UVLO pull-down feature
■ DIP-16, SO-16N package
L6599 Application:
■ LCD and PDP TV
■ Desktop, entry-level server
■ Telecom SMPS
■ AC -DC adapter, open SMPS
Figure 1.L6599 block diagram
Figure 2. Electrical circuit diagram of L6599 and L6563 90W adapter
Steval-ISA018V1 Evaluation Board
This user manual describes an efficient solution for industrial power supply with a continuous output power of 150 W, peak power up to 240W. It utilizes a resonant method to minimize switching losses, resulting in efficiency above 90%. This topology is based on a half bridge and is operated by a resonant LC resonator driven by the L6599 special controller.
This evaluation board provides a regulated output, VO = 24 V, IO = 6 A, the maximum overload capacity is IO = 10A. The output voltage and current are controlled by the TSM 1011 constant voltage constant current controller, providing a square output adjustment, and overload is on the output rectifier by thermal protection (PTC).
image 3. Steval-ISA018V1 profile
Steval-ISA018V1 main indicator:
Figure 4. Steval-ISA018V1 circuit diagram
Steval-ISA018V1 Material list:
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