Product overview
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. 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.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.
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).
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.
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.
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.
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All features
- 800 V, avalanche rugged internal power MOSFET
- 5% accuracy on constant LED output current with primary control
- Optocoupler not needed
- Quasi-resonant (QR) zero voltage switching (ZVS) operation
- Internal HV start-up circuit
- Open or short LED string management
- Automatic self supply
- Input voltage feed-forward for mains independent cc regulation
Circuit Diagram
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STMicroelectronics - HVLED805
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Quality and Reliability
| Part Number | Marketing Status | Package | Grade | RoHS Compliance Grade | Material Declaration** |
|---|---|---|---|---|---|
| HVLED805TR |
Active
|
SO-16 | Industrial | Ecopack2 |
(**) The Material Declaration forms available on st.com may be generic documents based on the most commonly used package within a package family. For this reason, they may not be 100% accurate for a specific device. Please contact our sales support for information on specific devices.
Sample & Buy
| Part Number | Order from Distributors | Order from ST | Marketing Status | ECCN (US) | ECCN (EU) | Packing Type | Package | Temperature (°C) | Country of Origin | Budgetary Price (US$)*/Qty | ||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| min | max | |||||||||||
| HVLED805TR | 1 distributors | Free Sample Buy Direct |
Active
|
EAR99 | NEC | Tape And Reel | SO-16 | - | - | THAILAND | 0.6185 / 1k | |
(*) Suggested Resale Price (USD) per defined quantity for BUDGETARY USE ONLY. For quotes, prices in local currency, please contact your local ST Sales Office or our Distributors