FAQ

What is the difference between a constant voltage and constant current driver?

A constant voltage driver regulates a specified output voltage. Designs using constant voltage supplies will need to regulate the current in their system. This can be advantageous in applications where the total number of LEDs for an installation is unknown or where added control is desired.  A constant current driver regulates a specified output current. Designs using constant current are able to easily connect the driver’s output directly to LEDs without added regulation. This is possible because LEDs respond directly to the current driven through them.

What is a constant power driver?

A constant power driver is a constant current driver in which the output current can be modified. As the output current setting decreases,  higher output voltage can be used from the driver making it possible to take full power from the driver in a wide range of output current settings. This allows for more freedom of design compared to regular constant-current drivers that derate as the output current decreases. For more information, see “Understanding the I-V Operating Area of Constant Power Drivers” in our Design in Guide.

How do I know which driver to select when there seem to be multiple options?

The best driver for any given design will depend on the load and the application. With this information, the application will define which features are needed for a design and ultimately which driver will be best. For more information, see “Defining Application Requirements to Select the Best LED Driver Family” in our Design in Guide or contact your local technical support for their recommendation.

What are PF and PFC and why are they important to specifying LED drivers?

Power Factor (abbreviated PF) is the ratio of real power to apparent power in an AC power system and is expressed as a number between 0 and 1. Real power is the actual power drawn by the load whereas apparent power is the product of the load current and load voltage. Since the voltage and current may be out of phase this product may be significantly greater than the real power.
In order to maintain a high power factor, switch mode power supplies (including LED drivers) must employ some form of power factor correction (PFC).

This is an important issue because a load with a low power factor draws more current than a load with a high power factor for the same amount of real power transferred. Low power factor therefore results in greater power losses in the utility lines. There are a number of standards now in effect requiring certain levels of power factor correction in switch mode power supplies and/or LED drivers.

What are the differences between MTBF and Lifetime?

Mean Time Between Failure (MTBF) represents the statistical approximation of the cumulative hours a number of units should operate before a failure can be expected. It does not represent the expected life of any given unit. For instance, if 10,000 units operated in the field for 1000 hours with 10 failures, the MTBF would be 1 million hours. This does not suggest that any unit will be expected to operate for 114 years. As another example, if the unit is determined to have an MTBF of 250,000 hours and 1000 units are deployed in the field, on average a failure could be expected about every 10 days if the drivers are operated around the clock or about once a month if they are operated 8 hours per day.
Conversely, the lifetime of a unit indicates how long it should be expected to survive under normal operating conditions. It is the period of time between starting to use the device and the beginning of the wear-out phase. This is determined by the life expectancy of components used in assembly of the unit. The weakest component with the shortest life expectancy determines the life of the whole unit. For power supplies, electrolytic capacitors typically have the shortest lifetime expectancy. MTBF is applicable only during the normal operating life of the product.

Do your metal case drivers perform better and have a longer life than the folded metal case drivers?

A good case design can greatly reduce the thermal impedance from case to surrounding air.  Aluminum is six times better than steel at conducting heat-this helps to spread the heat over the entire surface of the driver.  Two drivers can both have a life of 50,000 hours at a Tc of 60°C and yet yield very different life results in application due to efficiency and thermal design.  A difference of 10°C can yield a 2x difference in product life.

What is the difference between Class II and Class 2?

Class ‘2’ is derived from the North American UL 1310 Standard for Class 2 Power Units. To comply with UL 1310, the driver’s output must be isolated from the input and even under fault conditions must satisfy the following:

• Voltage Limited < 60Vdc
• Current Limited < 8A
• Power Limited < 100W

Drivers with a Class 2 output are evaluated to both UL 8750 and this additional UL 1310. They are considered safe to use with minimal risk of shock or fire. For example, a 12V car battery is not a Class 2 power source – it does not pose a risk of shock due to the low voltage, but it does pose a risk of fire due to the potential for high current (it is not current limited). Canada’s equivalent of UL 1310 is CAN/CSA-C22.2 No. 223.

Class ‘II’ is derived from IEC standards. LED drivers for class II luminaires are designed in such a way that protection against electric shock does not rely on basic insulation only. Additional safety precautions such as double insulation or reinforced insulation are provided, there being no provision for an protective earthing or reliance upon installation conditions. When such products are designed for / suitable for independent use (outside a luminaire), the are fully classified as class II and are marked by a double square symbol and if it is only suitable for built-in use (inside a luminaire) it is marked by a double circle symbol.

The difference between Class I and Class II being:

• Class I luminaires: provide 1) basic insulation and 2) earth continuity between metal accessible parts and the protective earth conductor
• Class II luminaires: provide double or reinforced insulation; designed to be safe without the protective earth conductor

Class 2 is related to the North American UL standard concerned with risk of electrical shock or fire from the output; whereas, Class II is related to the IEC standard concerned with safety from electrical shock on the input. Note: they are both pronounced “class two”.

How do I program an Inventronics LED driver?

The 0-10V and DALI programmable drivers utilize the PRG-MUL2 to interface with a computer. Written and video instructions are available to assist with downloading the software. For more information about using our interface, see “Programming” in our Design in Guide or view our additional walk-through videos. 

Can I program more than 1 driver at the same time?

No. For more information on this and programming our drivers, please visit our videos page.

Can I re-program your drivers when installed in the field already?

Yes.

Can I communicate digitally with your programmable drivers to read back data?

We offer a proprietary digital interface called “Digital Dimming” that is available on some of our drivers. If you have further questions on this, please reach out to your local sales representative.

How do I update your software? 

Software should automatically update. If it does not, the most recent software version is always available on our software page.

What’s the difference between Tc for Safety and Tc for Warranty?

Tc stands for case temperature. The Tc for safety is a temperature that is defined by the safety agency during safety evaluation. The Tc for warranty is based upon the correlated temperature and lifetime of the capacitors used within a design. For example, a design may be safe to operate with a case temperature of 90°C, but the components will not be able to withstand long-term operation with a case temperature of 90°C.

What is I2s and how does it relate to Inrush current?

Inrush current is the peak current that occurs when the driver is initially connected to the AC line.  In determining whether or not a current spike will blow an upstream fuse or trip a breaker, the key factor is the I2T rating. The I2T rating deals with the amount of energy in the spike.  It is the square of the current multiplied by the duration.  In short, the Inrush current is the peak current and the I2T rating is the average current over the duration.

How many drivers can I install on a circuit breaker?

We provide an application note that will help explain this in further detail.  For more information on this, please read our “Circuit Breaker App Note” found on our Application Notes page.

Are SELV circuits limited to 60 Vdc?

SELV is defined in both IEC/EN’s luminaire standard (IEC/EN 60598-1) and driver standards (IEC/EN 61347-2-13) stating:

-1.2.42
-ELV
-extra low voltage
-voltage which does not exceed 50 V a.c.r.m.s. or 120 V ripple free d.c.
between conductors, or between any conductor and earth (voltage band I of
IEC 60449)

The standard is focused on the system’s potential working voltage, requiring both the operational voltage and the no-load (open circuit) voltage to be <120Vdc. Unlike UL Class 2, the total power and current are not limited.

Notice that the SELV limit is 120Vdc max, not 60Vdc max. This maximum limit is often confused because there are added advantages when the voltage is less than 60Vdc. Advantages include: LED board creepage distance and clearance measurement exclusions as well as freedom to expose current carrying parts. Many designs benefit from limiting the working voltage to 60Vdc; however, this is not synonymous with the SELV requirements. SELV only requires the driver to maintain working voltages < 120Vdc.

*Note: The datasheet for constant power drivers list the worst-case no-load voltage. Once programmed, the no-load voltage is often much less than the written specification (typically 10 ~ 20% above the max voltage for the programmed output current). Please contact your local Inventronics representative to identify the right driver for your application.

What is the lowest dim level that your drivers can dim to? 

Most of Inventronics drivers operate down to 10% with standard passive dimmers. We do offer a few driver series that dim to 5% and to 1%.

What does dim-to-off mean and how does it work?

Dim-to-off is the ability for the driver to dim to a minimum dimming percentage and then to “off” where no current will be output causing the drivers to no longer illuminate. Though the driver is “dimmed-to-off”, the driver is still on and consuming typically < 0.5W. It is similar to the sleep mode on a computer.

What are the main differences between DALI and DALI-2?

The Digital Addressable Lighting Interface (DALI) was promoted in 2000 to offer a common standard for lighting interoperability. The certification and promotion was led by DALI AG under the ZVEI, German Electrical and Electronic Manufacturers Association. Under their guidance the standard grew and as the lighting industry matured, work on a new version (DALI-2) was started.  Various lighting companies joined together to form the Digital Illumination Interface Alliance (DiiA) and the key organization for promoting DALI on a global basis.

DALI-2 continues on the standardization and continuation of better interoperability and is designed to fill gaps in the original standard.  DALI-2 includes standardization of control devices; such as light sensors, push buttons and occupancy sensors. Some of the other benefits DALI-2 brings are:

• Support for colour controls
• Better reporting for energy usage and temperatures
• Significantly improved interoperability through more detailed testing
• Allows for up to 128 addresses on a single DALI network

DALI-2 compliant devices will have the official DALI-2 logo which can only be used by DiiA members.  Luminaires can carry the DALI-2 logo if all DALI bus-connected devices they contain are DAlI-2 certified.

What is the difference between DALI-2, D4i and Digital Dimming?

DALI-2 is the second generation of DALI allowing for increased interoperability, more stringent test protocols and extended commands.  DALI-2 is backwards compatible with most DALI systems and allows for increased compatibility.  Standard DALI-2 drivers will behave similarly to DALI drivers.

The D4i certification program is an extension to DALI-2 and is intended for intra-luminaire communication.  It is expected to launch by the DiiA very soon.  D4i requires and certifies the following features: 24V auxiliary supply, integrated DALI power supply, extended fixture information, AC power monitoring and diagnostic and maintenance data.

Digital Dimming allows users to read back information from a driver.  This feature is selectable in programming software and allows for the 0-10V leads to be utilized as a UART data bus. This allows users to set max output current, read output voltage and current, dim the driver, read driver information, read internal and external temperature and change dimming modes.  To see the complete list of Inventronics drivers that offer Digital Dimming, visit here.

Do you stock your drivers in the USA and Europe?

We have changing stock daily in our warehouse in the USA and Europe.  Our USA warehouse will stock UL recognized/Listed drivers and our warehouse in Europe stocks CE and ENEC certified drivers.

How long will it take to get your drivers if you don’t have stock?

Our average build time for a new product build is 9-11 weeks.

Can I buy my drivers directly from Inventronics or do I have to use one of your distributors?

Inventronics USA can sell direct but we require payment at the time of shipment.

What is your typical turnaround for POS to delivery?

If a driver is in stock, we will ship within 24-28 hours.

Do you offer extended warranties?

You will find information about our warranties by visiting here.

How do I start a warranty claim?

If you bought directly from Inventronics, please contact service@inventronics.global. One of our warranty administrators will respond with guidance.  If you didn’t buy directly from Inventronics, please work with the company from whom you purchased the drivers.