STMicroelectronics HVLED815PF Demonstration Board STEVAL-ILL044V1 STEVAL-ILL044V1 Fiche De Données
Codes de produits
STEVAL-ILL044V1
HVLED815PF
Device description
Doc ID 023409 Rev 4
15/36
4 Device
description
The HVLED815PF is a high-voltage primary switcher intended for operating directly from the
rectified mains with minimum external parts to provide high power factor (> 0.90) and an
efficient, compact and cost effective solution for LED driving. It combines a high-
performance low-voltage PWM controller chip and an 800 V, avalanche-rugged Power
MOSFET, in the same package.
rectified mains with minimum external parts to provide high power factor (> 0.90) and an
efficient, compact and cost effective solution for LED driving. It combines a high-
performance low-voltage PWM controller chip and an 800 V, avalanche-rugged Power
MOSFET, in the same package.
The PWM is a current-mode controller IC specifically designed for ZVS (Zero Voltage
Switching) flyback LED drivers, with constant output current (CC) regulation using primary
sensing feedback (PSR). This eliminates the need for the optocoupler, the secondary
voltage reference, as well as the current sense on the secondary side, while still maintaining
a good LED current accuracy. Moreover, it guarantees a safe operation when short-circuit of
one or more LEDs occurs.
Switching) flyback LED drivers, with constant output current (CC) regulation using primary
sensing feedback (PSR). This eliminates the need for the optocoupler, the secondary
voltage reference, as well as the current sense on the secondary side, while still maintaining
a good LED current accuracy. Moreover, it guarantees a safe operation when short-circuit of
one or more LEDs occurs.
The device can also provide a constant output voltage regulation (CV): it allows the
application to be able to work safely when the LED string opens due to a failure.
application to be able to work safely when the LED string opens due to a failure.
In addition, the device offers the shorted secondary rectifier (i.e. LED string shorted due to a
failure) or transformer saturation detection.
failure) or transformer saturation detection.
Quasi-resonant operation is achieved by means of a transformer demagnetization sensing
input that triggers MOSFET turn-on. This input serves also as both output voltage monitor,
to perform CV regulation, and input voltage monitor, to achieve mains-independent CC
regulation (line voltage feedforward).
input that triggers MOSFET turn-on. This input serves also as both output voltage monitor,
to perform CV regulation, and input voltage monitor, to achieve mains-independent CC
regulation (line voltage feedforward).
The maximum switching frequency is top-limited below 166 kHz, so that at medium-light
load a special function automatically lowers the operating frequency while still maintaining
the operation as close to ZVS as possible. At very light load, the device enters a controlled
burst-mode operation that, along with the built-in high-voltage startup circuit and the low
operating current of the device, helps minimize the residual input consumption.
load a special function automatically lowers the operating frequency while still maintaining
the operation as close to ZVS as possible. At very light load, the device enters a controlled
burst-mode operation that, along with the built-in high-voltage startup circuit and the low
operating current of the device, helps minimize the residual input consumption.
Although an auxiliary winding is required in the transformer to correctly perform CV/CC
regulation, the chip is able to power itself directly from the rectified mains. This is useful
especially during CC regulation, where the flyback voltage generated by the winding drops.
regulation, the chip is able to power itself directly from the rectified mains. This is useful
especially during CC regulation, where the flyback voltage generated by the winding drops.
4.1 Application
information
The device is an off-line led driver with all-primary sensing, based on quasi-resonant flyback
topology, with high power factor capability. In particular, using different application schematic
the device is able to provide a compact, efficient and cost-effective led driver solution with
high power factor (PF>0.9 - see application schematic on
topology, with high power factor capability. In particular, using different application schematic
the device is able to provide a compact, efficient and cost-effective led driver solution with
high power factor (PF>0.9 - see application schematic on
) or with standard power
factor (PF>0.5/0.6 - see application schematic on
), based on the specific
application requirements.
Referring to the application schematic on
, the IC modulates the input current in
according to the input voltage providing the high power factor capability (PF>0.9) keeping a
good line regulation. This application schematic is intended for a single range input voltage.
good line regulation. This application schematic is intended for a single range input voltage.
For wide range application a different reference schematic can be used; refer to the
dedicated application note for further details.
dedicated application note for further details.
Moreover, the device is able to work in different modes depending on the LED's driver load
condition (see
condition (see