NXPSSL2108x High Efficiency General Lighting LED Driver Reference Design

NXP’s SSL2108x series are high-voltage integrated circuits, mainly used to drive non-dimmable LED lamps for general lighting, with an efficiency greater than 95%. The device integrates a 300 V or 600 V power switch and has various protection functions such as undervoltage lockout (UVLO), Leading Edge Blanking (LEB), Over Current Protection (OCP), Short Winding Protection (SWP), Over Temperature Protection (OTP) and Short Circuit Protection (OSP). This paper introduces the main features and advantages of SSL2108X, block diagram, Basic application block diagram and buck converter configuration diagram along with evaluation board key features, circuit diagram and bill of materials (BOM).

The SSL2108X is a range of high-voltage Integrated Circuits (ICs), intended to drive non-dimmable retrofit LED lamps in general lighting applications.

The main benefits of the product family are:

•Small Printed-Circuit Board (PCB) footprint, and compact solution

•High efficiency (up to 95 %)

•Ease of integration

•Low Electronic Bill Of Material (BOM)

The product family is made of ICs with a range of internal HV switches for easy power scaling.

The ICs work as boundary conduction mode buck converters. The IC range has been designed to start up directly from the HV supply by an internal high-voltage current source. Followed by the dV/dt supply using capacitive coupling from the drain, or any other auxiliary supply. This functionality provides full flexibility in the application design. The supply current consumed by the IC is 1 mA, an internal clamp limits the supply voltage.

The ICs provide accurate output current control with greater than 5 % LED current accuracy. The ICs can be operated using Pulse-Width Modulation (PWM) dimming and has many protection features including easy LED temperature feedback.

SSL2108X main features and advantages:

LED driver IC family driving strings of LEDs from a rectified mains supply

High-efficiency switch mode buck driver product family:

Drivers with integrated 300 V or 600 V power switches

Controller with power-efficient boundary conduction mode of operation with:

No reverse recovery losses in freewheel diode

Zero Current Switching (ZCS) for turn-on of switch

Zero voltage or valley switching for turn-on of switch

Minimal required inductance value and size

Direct PWM dimming possible

Fast transient response through cycle-by-cycle current control:

Negligible AC mains ripple at LED current and minimal total capacitor value

No over or undershoots in the LED current

No binning on LED forward voltage required

Internal Protections:

UnderVoltage LockOut (UVLO)

Leading-Edge Blanking (LEB)

Over Current Protection (OCP)

Short-Winding Protection (SWP)

Internal OverTemperature Protection (OTP)

Brownout protection

Output Short Protection (OSP)

Low component count LED driver solution:

No Schottky diode required due to ZCS

No dim switch and high-side driver required for PWM dimming

Easy external temperature protection without additional components

Option for soft-start function

Hotaru switch compatible during standby1

IC lifetime easily matches or surpasses LED lamp lifetime

SSL2108X application: 

SSL2108X products are intended for compact LED lamp ballasts with accurate fixed current output for single mains input voltages. Mains input voltages include 100 V, 120 V and 230 V (AC). The output signal can be modulated using a PWM signal.
NXPSSL2108x High Efficiency General Lighting LED Driver Reference Design
Figure 1. SSL2108X block diagram
NXPSSL2108x High Efficiency General Lighting LED Driver Reference Design
Figure 2. Basic application block diagram of SSL2108X
NXPSSL2108x High Efficiency General Lighting LED Driver Reference Design
Figure 3. SSL21081/SSL21083 Buck Converter Configuration Diagram
NXPSSL2108x High Efficiency General Lighting LED Driver Reference Design
Figure 4. SSL21082/SSL21084 Buck Converter Configuration Diagram

Line Voltage 230VAC 50Hz Evaluation Board

The board is optimized for a 230 V (AC, 50 Hz) mains supply. In addition to the mains voltage optimization, the board is designed to work with multiple LEDs or an LED module with a high forward voltage.

Mains connection of this reference board is different from other general evaluation/demo boards. Connect the mains to the screw connector J6.

Remark: The maximum rated voltage of the board is 280 V (limited by the value of electrolytic capacitor C1) or 400 V (DC).

The anode of the LED load is connected to positive positions 1 to 3 of connector J5. The cathode is connected to negative positions 4 to 6 of connector J5.

Use an LED string with a VF greater than 20 volt on this board. Under the expected conditions, the output current is 96 mA. If the rated current of the LED does not meet this specification, the current can be adjusted.

NXPSSL2108x High Efficiency General Lighting LED Driver Reference Design
Figure 5. Evaluation Board Outline Drawing
Evaluation Board Power Specifications:
NXPSSL2108x High Efficiency General Lighting LED Driver Reference Design
NXPSSL2108x High Efficiency General Lighting LED Driver Reference Design
Figure 6. Evaluation Board Circuit Diagram
Evaluation Board Bill of Materials:

For details, see:
http://www.nxp.com/documents/data_sheet/SSL2108X.pdf
and
http://www.nxp.com/documents/user_manual/UM10502.pdf

The Links:   6DI100M-050 2MB1300NB-060