Installation Guide

LED Lighting Surge Protection Modules

Design and Installation Guide

The following steps summarize a design process that helps ensure enough inductance is

present between the SPD MOVs and the one in the driver:

1. MOV1 and MOV2 need to be coordinated so that most of surge current/energy ﬂows

through MOV1.

2. Select MOVs with V

of MOV1 ≤ V

of MOV2, where V

is the Maximum Continuous

Operating Voltage.

3. Select MOVs with V

of MOV1 ≤ V

of MOV2, where V

is the Maximum

Clamping Voltage.

4. V

MOV1

= V

MOV2

+ L (di/dt)

5. Inductance L may be added in series with the SPD. Increasing inductance L will result in

better coordination as MOV1 absorbs the higher surge energy

6. Refer to the embedded links in the SPD blocks of Figure 17 for MOV technical

information. See the Littelfuse Varistor Ordering Information Diagram for details on

constructing a part number.

The Littelfuse Application Team has years of expertise in such coordination requirements and

has helped many customers optimize their circuit reliability while meeting surge immunity

requirements.

Power Supply Unit Design Considerations (Fuse, Equivalent

Resistance, TVS Diode)

Although an SPD module is designed to absorb most of the surge energy produced by

a lightning strike, some residual energy can enter the LED driver and cause damage to

the components inside it (Figure 18). To minimize the damage, always consider an LED

driver design that works in cooperation with the SPD module so less energy can enter the

LED driver.

Power Supply Unit Design Considerations