Keeping the Lights On: Safeguard LED Lighting with Proper Circuit Protection Day 1: LED Lighting Overview & The Importance of Circuit Protection

Agenda Day 1: LED Lighting Overview & The Importance of Circuit Protection Day 2: LED Lighting Circuit Protection Applications Day 3: LED Lighting Standards

LED Lighting Overview & The Importance of Circuit Protection Creating designs for LED lighting applications presents several challenges, including the need to protect the sensitive electronics and circuits against over-current, over-voltage and lightning/transient surges. These electrical threats may jeopardize the safety of personnel and endanger the consumer’s ROI. If proper safeguards are not used, there could also be compliance issues with regulatory and safety standards related to over-voltage transients.

LED Lighting Overview & The Importance of Circuit Protection Today’s session addresses: LED Lighting market growth What is circuit protection? Why is it important to LED Lighting? What are the issues designers should be aware of in the development of their designs?

That’s A LOT of GROWTH! But why is LED Lighting circuit protection important? To succeed in this market, electronics engineers must incorporate reliable circuit protection that deliver a strong ROI for their LED designs. Why? Reliability Safety Protect Technology Protect Life

What IS Circuit Protection? Vital elements in applications from consumer electronics and telecom circuits to automobiles and industrial equipment. Protects sensitive electronics against harm caused by: over-currents, over-voltages, electrostatic discharge (ESD), lighting surges, and other electrically harmful occurrences. What exactly is electronic circuit protection? Circuit protection components are vital elements in applications from consumer electronics and telecom circuits, to automobiles and industrial equipment. They protect sensitive electronic devices and business assets against harm caused over-currents, over-voltages, electrostatic discharge (ESD), lighting surges, and other electrically harmful occurrences.

Why Circuit Protection is Crucial For protecting people For protecting technology For protecting businesses and their brand’s reputation Circuit protection components are vital in a broad range of electrical and electronic design applications because they protect people, electronic devices, and business assets (equipment, buildings) from harm.

Where Circuit Protection Is Used In virtually every electrical and electronic device made today, including: Consumer Electronics Automotive Components LED Lighting Telecom Industrial Designing the appropriate circuit protection is critical to preventing dangerous products from reaching the public. Example: Lithium ion cells, like the ones in laptops, are subject to thermal runaway. Raising the temperature of a Li-ion battery above the 140 degree F mark leads to a compromised cell which causes an explosion and a resulting fire. Battery packs for laptops and other portable devices contain many levels of protection to assure safety under (almost) all circumstances when in the hands of the public. The safety begins with the battery cell, which includes: [1] a built-in temperature switch called PTC that protects against high current surges, [2] a circuit interrupt device (CID) that opens the electrical path if an over-charge raises the internal cell pressure to 1000 kPa (145psi), and [3]a safety vent that releases gas in the event of a rapid increase in cell pressure. In addition to these internal safeguards, an external electronic protection circuit prevents the charge voltage of any cell from exceeding 4.30V. Furthermore, a fuse cuts the current if the skin temperature of any cell approaches 90°C (194°F). To prevent the battery from over-discharging, a control circuit cuts off the current path at about 2.20V/cell. (Content on battery protection from: http://batteryuniversity.com/learn/article/safety_circuits_for_modern_batteries).

Circuit Protection Device Types Cartridge Fuses Positive Temperature Coefficient (PTC) Fuses Gas Discharge Tubes (GDT) Varistors (MOV, TMOV) Polymer ESD Suppressors Transient Voltage Suppression (TVS) Diodes Protection Thyristors TVS Diode Arrays SIDACtor Devices LED Protectors (PLED) What kinds of circuit protection devices are available to device designers? Common types of circuit protection devices for electronic products include: fuses, GDTs (Gas Discharge Tubes), resettable PTCs, varistors, ESD Suppressors (Pulseguard), TVS diodes, TVS diode arrays, SIDACtor devices, and PLEDs (LED protectors)

Example of Poorly Planned Circuit Protection IC Power Port MOV (Metal Oxide Varistor) D+ DC An MOV protects against over-voltage events A fuse protects against over-current into the IC…AND excessive current into the MOV Fuse ?? MOV1 MOV2 LF TMOV Included a screen cap from the MOV v TMOV test video. (Video not included in PPT. Provide link for Design News to share.)

Real World Examples of Ignoring Circuit Protection What can happen when there’s insufficient circuit protection? Designing the appropriate circuit protection is critical to preventing dangerous products from reaching the public. Example: Lithium ion cells, like the ones in laptops, are subject to thermal runaway. Raising the temperature of a Li-ion battery above the 140 degree F mark leads to a compromised cell which causes an explosion and a resulting fire. Battery packs for laptops and other portable devices contain many levels of protection to assure safety under (almost) all circumstances when in the hands of the public. The safety begins with the battery cell, which includes: [1] a built-in temperature switch called PTC that protects against high current surges, [2] a circuit interrupt device (CID) that opens the electrical path if an over-charge raises the internal cell pressure to 1000 kappa (145psi), and [3]a safety vent that releases gas in the event of a rapid increase in cell pressure. In addition to these internal safeguards, an external electronic protection circuit prevents the charge voltage of any cell from exceeding 4.30V. Furthermore, a fuse cuts the current if the skin temperature of any cell approaches 90°C (194°F). To prevent the battery from over-discharging, a control circuit cuts off the current path at about 2.20V/cell. (Content on battery protection from: http://batteryuniversity.com/learn/article/safety_circuits_for_modern_batteries).

Circuit Protection IS a Critical Part of Design! Circuit protection is a critical part of the circuit design process All too often though, circuit protection is the last thing some engineers think about because they prioritize designing the core functionality of their devices as quickly as possible. Circuit protection should NEVER be an afterthought!

Consequences of Thinking About CP Too Late You may need to redo the board layout, which costs money and results in lost development time A less-than-optimal protection device or location, which results in functional failures, poor reliability, safety issues, shock or even fire The best time to start thinking about circuit protection is AFTER the chipset has been selected and BEFORE beginning to lay out the circuit boards. Potential consequences of making circuit protection an afterthought: Once the PCB is designed, engineers may have difficulty finding room for circuit protection devices, forcing them to re-layout the boards, costing their employer more money and losing valuable development time Even if they don’t have to re-layout the board, time pressure may cause them to choose a less-than-optimal protection device or putting a device in a non-optimal location, resulting in functional failures, poor reliability, safety issues, shock, or even fire. Best time to start thinking about circuit protection is after the chip set has been selected and before beginning to lay out circuit boards. At this point, ESD ratings are available and designers can know how robust or how sensitive the chips are.

Bottom line: All LED lighting applications are subject to damaging transient surges!

Typical Residential LED Lamp Construction Add key talking points in notes, if needed.

Typical LED Luminaire Driver Circuit with Transient and Surge Energy Protection Devices Purpose of this slide is to provide a top-level overview of the different CP required in a robust LED driver design (AC fuse, MOV, HV DC fuse, TVS diodes, PTC and PLED). THE INTENT is NOT to cover this in detail in Session 1. Will cover in DETAIL in Session 2 (Applications).

Designers should be aware of the following issues… Know the threats to LED lighting design: Over-current, over-voltage, lightning/transient surges. Proper protection of ALL electronics/circuits begins with realization that several levels of protection are necessary for a robust design. Today’s advanced chipsets are more susceptible to damage from ESD and other sources of transient surges It’s important to have an awareness/understanding of what’s required to comply with global regulations and standards.

Coming Tomorrow… LED Lighting Circuit Protection Applications <images of applications here>

Thank You for your attention! Any question?