. General description
The SSL4120 integrates a Power Factor Corrector (PFC) controller and a controller for a
Half-Bridge resonant Converter (HBC) in a multi-chip IC. It provides the drive function for
the discrete MOSFET in an up-converter and for the two discrete power MOSFETs in a
resonant half-bridge configuration.
Efficient PFC operation is achieved by implementing functions for Quasi-Resonant (QR)
operation at high-power levels and QR with valley skipping at lower power levels.
OverCurrent Protection (OCP), OverVoltage Protection (OVP) and demagnetization
sensing ensure safe operation under all conditions
The HBC module is a high-voltage controller for a zero-voltage switching LLC resonant
converter. It contains a high-voltage level shift circuit and several protection circuits
including OCP, open-loop protection, capacitive mode protection and a general purpose
latched protection input.
The high-voltage chip is fabricated using a proprietary high-voltage Bipolar-CMOS-DMOS
power logic process enabling efficient direct start-up from the rectified universal mains
voltage. The low-voltage Silicon-On-Insulator (SOI) chip is used for accurate, high-speed
protection functions and control.
The SSL4120 controlled PFC circuit and resonant converter topology is very flexible. It
can be used for a broad range of applications over a wide mains voltage range.
Combining PFC and HBC controllers in a single IC makes the SSL4120 ideal for
controlling compact power supplies in lighting applications, such as LED drivers.
Using the SSL4120, highly efficient and reliable power supplies providing over 100 W can
be designed easily which use the minimum of external components.
Remark: Unless otherwise stated, all values are typical.
Features and benefits
2.1 General features
Integrated PFC and HBC controllers
Universal mains supply operation from 85 V to 305 V (AC)
High level of integration resulting in a low external component count and a cost
effective design
Enable input to enable only the PFC or both the PFC and HBC controllers
On-chip high-voltage start-up source
Stand-alone operation or IC supplied from external DC source
2.2 PFC controller features
Boundary mode operation with on-time control
Valley/zero-voltage switching for minimum switching losses
Frequency limiting to reduce switching losses
Accurate boost voltage regulation
Burst mode switching with soft-start and soft-stop
2.3 HBC controller features
Integrated high-voltage level shifter
Adjustable minimum and maximum frequency
Maximum 500 kHz half-bridge switching frequency
Adaptive non-overlap time
Burst mode switching
2.4 Protection features
Safe restart mode for system fault conditions
General latched protection input for output overvoltage protection or external
temperature protection
Protection timer for time-out and restart
Overtemperature protection
Soft (re)start for both controllers
Undervoltage protection for mains (brownout), boost, IC supply and output voltage
Overcurrent regulation and protection for both controllers
Accurate overvoltage protection for the boost voltage
Capacitive mode protection for the HBC controller
3. Applications
The IC is used in all LED lighting applications that require very efficient, low Total
Harmonic Distortion (THD), high Power Factor (PF) and a universal mains input voltage.
The SSL4120 provides a cost-effective power supply solution between 25 W and 400 W
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