Powerint LNK458KG4.3W PFC LED driver reference design (DER297)

The LED driver uses the LinkSwitchTM-PL series LNK458KG, which is mainly used for B10 replacement lamps. The efficiency is greater than 86% at 115 VAC input and 48V output, and greater than 87% at 115 VAC input and 96V output. The power factor is greater than 0.95, the THD is less than 15%, and the start-up time is less than 300ms. This article introduces the main advantages of the LED driver reference design and the main indicators, circuit diagrams and corresponding bill of materials of the output 48 V/90 mA, 48 V/ 60 mA and 96 V/ 45 mA reference designs.
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4.3 W Power Factor Corrected LED Driver (Non-Isolated Buck Boost) Using LinkSwitchTM-PL LNK458KG

This document is an engineering report describing a non-isolated LED driver (power supply) utilizing a LNK458KG from the LinkSwitch-PL family of devices.

The DER-297 provides a single constant current output with an output power of 4.5 W.

The board can be easily configured for output voltages from 35 V to 100 V as shown in the example table below.

The key design goals were high efficiency and small size, enabling the driver to fit into candelabra and B10 sized lamps and maximize efficacy.

The board was optimized to operate over the low AC input voltage range (85 VAC to 132 VAC, 47 Hz to 63 Hz). LinkSwitch-PL based designs provide a high power factor (>0.95) meeting current international requirements.

The form factor of the board was chosen to meet the requirements for standard B10 LED replacement lamps. The output is non-isolated and requires the mechanical design of the enclosure to isolate the output of the supply and the LED load from the user.

The design was not optimized for operation with phase controlled (TRIAC) dimmers but this is possible with some modification will reduce efficiency.

The document contains the power supply specification, schematic, bill of materials, transformer documentation, printed circuit layout, design spreadsheet and performance data.

LED driver reference design main features:

 Single-stage power corrected and accurate constant current factor ( CC) output

 Low cost, low component count and small PCB footprint solution

 Highly energy efficient, >86 % at 115 VAC input for 48 V and >87 % for 96 V output

 Superior performance and end user experience

 Fast start-up time (<300 ms) – no perceptible delay

 Integrated protection and reliability features

 Single shot no-load protection / output short-circuit protected with auto-recovery

 Auto-recovering thermal shutdown with large hysteresis protects both components and PCB

 No damage during brown-out conditions 

PF >0.95 at 115 VAC  %A THD

<15% at 115 VAC  Meets IEC ring

wave, differential line surge and EN55015 conducted mA reference design specifications: Figure 2. 48 V, 90 mA reference design circuit diagram Figure 3. 48 V, 60 mA reference design circuit diagram Figure 4. 96 V, 45mA reference design circuit diagram 48 V, 90 mA reference design bill of materials: 48 V, 60 mA reference design bill of materials:



















Make the following changes to modify the design from 48 V, 90 mA to 48 V, 60 mA.

96 V, 45 mA Reference Design Bill of Materials:
Make the following changes to modify the design from 48 V, 90 mA to 96 V, 45 mA.

For details, see:
http://www.powerint.com/sites/default/files/PDFFiles/der297.pdf