STMicroelectronics HVLED805 Demonstration Board STEVAL-ILL037V1 STEVAL-ILL037V1 Ficha De Dados
Códigos do produto
STEVAL-ILL037V1
HVLED805
Description
Doc ID 18077 Rev 1
3/29
1 Description
The HVLED805 is a high-voltage primary switcher intended for operating directly from the
rectified mains with minimum external parts to provide an efficient, compact and cost
effective solution for LED driving. It combines a high-performance low-voltage PWM
controller chip and an 800V, avalanche-rugged power MOSFET, in the same package.
rectified mains with minimum external parts to provide an efficient, compact and cost
effective solution for LED driving. It combines a high-performance low-voltage PWM
controller chip and an 800V, avalanche-rugged power MOSFET, in the same package.
The PWM is a current-mode controller IC specifically designed for ZVS (zero voltage
switching) fly-back LED drivers, with constant output current (CC) regulation using primary-
sensing feedback. This eliminates the need for the opto-coupler, the secondary voltage
reference, as well as the current sense on the secondary side, still maintaining a good LED
current accuracy. Moreover it guarantees a safe operation when short circuit of one or more
LEDs occurs.
switching) fly-back LED drivers, with constant output current (CC) regulation using primary-
sensing feedback. This eliminates the need for the opto-coupler, the secondary voltage
reference, as well as the current sense on the secondary side, still maintaining a good LED
current accuracy. Moreover it guarantees a safe operation when short circuit of one or more
LEDs occurs.
In addition, the device can also provide a constant output voltage regulation (CV): it makes
the application able to work safely when the LED string opens due to a failure.
the application able to work safely when the LED string opens due to a failure.
Quasi-resonant operation is achieved by means of a transformer demagnetization sensing
input that triggers MOSFET’s 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 feed forward).
input that triggers MOSFET’s 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 feed forward).
The maximum switching frequency is top-limited below 166 kHz, so that at medium-light
load a special function automatically lowers the operating frequency 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 start-up circuit and the low
operating current of the device, helps minimize the residual input consumption.
load a special function automatically lowers the operating frequency 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 start-up 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 fly-back 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 fly-back voltage generated by the winding drops.
In addition to these functions that optimize power handling under different operating
conditions, the device offers protection features that considerably increase end-product’s
safety and reliability: auxiliary winding disconnection or brownout detection and shorted
secondary rectifier or transformer’s saturation detection. All of them are auto restart mode.
conditions, the device offers protection features that considerably increase end-product’s
safety and reliability: auxiliary winding disconnection or brownout detection and shorted
secondary rectifier or transformer’s saturation detection. All of them are auto restart mode.