Right. Hello, everyone. Welcome to the High Voltage Seminar. This session is titled "Isolated Gate Driver 101-- from Insulation Spec to End Equipment Requirements." This session is being presented by Wei Zhang, applications manager for Texas Instruments high power drivers.

My name is Sean Alvarado, and I'll be the moderator for this session. All participants are muted in the session. Please use the chat function to ask a question and address it to everyone. We will be reserving 10 minutes at the end of the session to answer questions submitted in chat. Also use the chat if you're having any problems hearing or seeing the presentation.

With that, I'll hand it off to Wei to start the presentation.

Good morning, everyone. Thank you, Sean, for the introduction. Today we are talking about "Isolated Gate Driver 101-- from the Insulation Spec to End Equipment Requirements." In this presentation, we have a few points that we want to address. We will discuss the fundamentals.

And next, we will discuss the insulation specifications and how to verify them. And in the end, we're going to close it with examples and how do we utilize this knowledge into an end equipment system. Here, we are discussing one example for server and telecoms right here. And in the end, we're to have questions and answers.

Here is shown an example of the server and telecom from the AC line to the brick module in the telecom system. So you can see here we have the AC line, we have an EMI filter, PFC, now we're having [INAUDIBLE] DC to DC, which is quite popular. And the output is nominal 48 volts, but it can range from 36 to 75 volts. In these cases, I'm showing you 60 volts, which handles the majority of the cases.

And followed by this 48-volt [INAUDIBLE] there will be a brick module. Or we call it a brick converter that is having a certain amount of isolation and also turning from 48 volts to the 3.3 volts, 5 volts, 9.6 volts, 12 volts, or even 48 volts, just with isolation. And why the isolation is required, I mean, in the multiple system?

And the first reason comes is safety. And there are a lot of other reasons like, OK, you want to have 400 volts, 48 volts with a [INAUDIBLE] ratio to maximize your equipment duty cycle. There's also signal communication, breaking the grounding loop, to control the terminal noise, and also working for conditions where the bus voltage is higher than 600 volts. The majority of the nonisolated drivers having the junction working voltage up to 700 volts. If you want working for 800 volts or even 1,200 volts, the best choice is isolated driver, because isolation can handle high voltage.

So and the next line is performance high CMTI. So CMTI for non-iso driver roughly sitting less than 50 volts per nanosecond. But for iso driver, the majority of the drivers in our family is minimum 100 volts per nanosecond. And we are also working on the next generation, which is 200 volts per nanosecond, which is really a very significant improvement going from non-iso to iso for very high power density and high frequency application.

But nonetheless, of these benefit, the first and the most important one is safety. And today we are discussing why and how and what about the safety and using for the power converter system. There are three types which are pretty popular used in a variety of applications. We know the optical-based iso driver, which started from 1970s, you know, the optical isolation technology.

And starting from 2010, people are starting to work on next improved isolation technology, like inductive and capacitive, which is commercialized roughly about after 2005. So this is relatively new [INAUDIBLE] over 10 years of multiple generations of devices, you can see on the market about inductive isolated gate driver and a capacitive isolated gate driver.

Going through the advantages of the three categories, you can see the optical is very long history. It's been proven, working very solid, and have low emissions. inductive and capacitive share a lot of common feature, because they are almost-- they're all silicon dioxide-based isolation barrier.

So you can see it is fast. It is low power. It is very high noise mu on CMTI. It is very low channel-channel skew. I mean, if you're looking at the opto-coupler based part, the part variation is most of time sitting around 50 nanoseconds. And if you go to the inductive and the capacitive, the channel-channel matching skew is less than 5 nanoseconds.

For sure, you can find very high performance in a very expensive opto-coupler capital which can also reach similar performance. But that will be very-- either very lossy or very high cost. But for inductive and capacitive isolation, it is very common. It is most of the drivers that can achieve similar performance at a very low part-part or channel-channel skew.

But talking about inductive and capacitive isolation, what is the major difference? The major difference is the high working voltage. That is what TI is having all the isolators, sensors, iso drivers, in building this technology based upon. So that is the capacitive isolation, which offers you a very high working voltage. If you want-- OK, I'm working on the 1,000 volts RMS over 40 years, here you go. We only have one choice. Capacitive isolation.

So to go into the isolation grades, you have functional, basic, supplementary, double, reinforced. There are so many words. But what is the really difference between these two? For functional isolation, it is mainly used for ground bouncing, high voltage. And sometimes you want to handle 700 volts or few hundred volts transient between two grounds. For example, the back converter you have 40 volts, which is pretty safe. 12 volts is pretty safe.

But there will be some transient coming from the battery side, [INAUDIBLE] battery side, which the transient is less than 1.5 kV. And for that scenario, functional isolation will be fitting the best. But when it's coming to the safety, protection and safety, in case, of single-level fails, you need double isolation.

And what is reinforced isolation? Reinforced isolation, in a single device you can achieve the double isolation. So that is where the reinforced isolation comes. So long story short, functional isolation is really just for proper operation of the circuit-level performance. And for basic isolation, it is protecting the equipment. That's what reinforced and double insulation is protecting the human.

And here is the example which I believe you see a lot of materials in ti.com or in Google, finding, what is the construction, how does the high-voltage capacitor look in the isolated driver from TI? So you see here we have a transmitter die, left side die. You have the receiver die, which is the right die in the picture in the upper left.

And you have some die-to-die distance, which is here is 600 micrometers. You also have in each-- we have two series capacitors, one in each die. And summing the distance through insulation together, we are reaching larger than 21 micrometers in terms of the distance for insulation. And every micrometer will handle over 500 volts-- 500 volts. So you can see the, how to say, the capacity of the insulation is very, very strong.

And that's why in our datasheet, we are reaching 12.8 kV peak surge voltage, 8 kV peak transient, and most importantly, compared with inductive isolation, you are seeing 1.5 kV RMS working voltage. And for all-- across all the reinforced isolation gate drivers. And this is by far in the industry the top of the line.

And for the extended package in TI we call DWW, which is 14-millimeter creepage. You can even work in a higher voltage. Because 1.6 volts kV RMS is required by the IEC standard. With 8-millimeter creepage, you can only operate in up to 1.6 kV. So that's where-- what is the magic number 1.5. Basically, the driver's internal capacity can work in really high voltage. It's really limited by the packaging. And what I'm talking about is the creepage distance.

And going to the datasheet of the iso gate drivers, you can find, OK, there are so many things. Just talking about isolation, without regard to other electrical parameters which are going to make the driver function, but isolation, going over, you can see the CLR, clearance; CPG, creepage; DTI, Distance Through Insulation.

And you also see a lot of standards-- UL 15577-- 1577. Also, you also see DIN VDE 0884-11-10. You also see IEC 60747-5-5. And also, you see a lot of working-- I mean, these voltage parameters-- V this, V that, and R this, CIO. So it's very intensive.

And if you go into the parameters-- and everyone-- I mean, if you're new to isolation, your head is spinning. So many parameters-- what are they? What does it mean? What is the purpose of this parameter? So how do I relate this one to my real application? And how do you guys, the semiconductor company, verify these parameters?

I mean, what-- if it has been certified, what it's been certified for? What are they testing? What is difference of this standard? That is raising a lot of questions. And in this presentation, we're going to address them one by one.

But in the beginning, before you address this, what is the purpose of all these parameters? What do these serve the function? What do they try to tell us? So here I list a few of my best understanding.

You see the-- I mean, it is, one, proves the electrical stresses, mechanical stresses, thermal and environmental influences, you want to make sure that, OK, the driver-- the iso driver or isolator have the capability for basic, supplementary, and reinforced insulation barrier to withstand all these stresses.

And that's what this-- all of these parameters during the previous page showed for. Because the driver has to withstand electrical, has to withstand mechanical, has to withstand thermal, and also a lot of other environmental influences.

Now we're coming to-- OK, we have so many parameters. But where does it belong to? What is-- is it for this component, or is it for the end equipment, or is it for some other supporting standards? So here is a very comprehensive-- you may have a lot of information right here, but I'm going to help you sort it out.

In the category, we have component standards. We just have the component nothing else. We also have equipment standard-- where this component we use it in, and also have some common supporting standard, which this, we call it, IEC 60664. So go to every this category.

And for component, you see opto, you see magnetic, capacitive. You'll see-- you also saw some UL 1577, which is used for opto-coupler and digital isolator. And for equipment, oh, there are many equipment. You have server telecom in the information technology. You have for the control and lab, you have medical, you have motor drive [INAUDIBLE] you have so many end equipment.

But all of this end equipment standard is based on the supporting standard, which is IEC 60664-1, which is insulation, coordination for low-volt system up to 1.5 TDDB. So that is telling, OK, you have components, you have end equipment, and you have some common lab range from IEC 60664 you can draw the knowledge from.

And going to each category of this standard, you can find, OK, not all these parameters is being addressed in every standard. Only, for example, VDE dash-- VDE 0884-10, -11 only addressing the TDDB. TDDB is Time Dependent Dielectric Breakdown, which is telling you how long this driver will operate and maintain its isolation in this working voltage.

So you can see the differences between all of these categories. And when you're talking about clearance, creepage, pollution degree, these are all system related. Because inside of the chip, it is pretty clean. There's no pollution degree for the [INAUDIBLE] internally is pollution degree number one.

So that can tell you basically structure-- OK, this parameter belongs here, and what are they basically talking about. So we start from the first one, RIO and CIO. And this is also a very common question that customer is asking. If you go through the internal structure for the opto, for the inductive, for the capacitor, you can see-- because in the real world, you can-- even in the optical, you can see the mold compound. You can see the junction to junction have capacitance. Even for inductive, you also have copper layer to copper layer, so [INAUDIBLE] myriad of silicon dioxides [INAUDIBLE] capacitor. So you have present here and there.

And they are all summarized into RIO and CIO. And in the optical and capacitive, and inductive isolation, you still have [INAUDIBLE] capacitance. Wherever you see two coppers, you are having a [INAUDIBLE] capacitance. And for sure, RIO is where you want-- making sure the voltage is being blocked [INAUDIBLE].

They are tested it with a given specification. And the resistance, we measure in in 500 volts in different temperature. So basically, this is a universal standard applied for every category. So CIO is the input-to-output capacitance. RIO is the input-to-output resistance.

So that is telling me, OK, in the real world, you can see what these parameters are coming from. And the-- also changing from, let's say, T safe is a safe temperature, which is 150 C, ambient max, and ambient.

And the next one is VISO and VIOTM. VISO is the maximum withstanding isolation AC voltage for one minute. And this is [INAUDIBLE] spec for UL 1577, tested either using DC or AC, meaning the new information here is, most of the time you see, oh, it's AC. But it can be DC. It's fine.

VIOTM is the maximum transient voltage, which is just the peak of the AC with 1.414 times VISO. So what is the purpose of VIOTM? It verifies the ability of the device to withstand the isolation test voltage under specified conditions for a short period. For this short period it means, in IEC, it's depending 1 second or 2 second at 100% of this value of maximum of 1.2 times of 1 minute region.

So UL, it has been tested 1 second. You have to be applying a 1.2 times 3. So if you are 3 kV, you have to be testing at 3.6 kV for 1 second. And it's been tested for 25 degrees C.

So for here, if I see a routine test, routine test means every part has to finish this test. In the final test, we automatically test the equipment before it reaches into your side. So it is a production tested item.

And VIOWM and VIORM, you see here, it is not a routine test. It is type test. That is pretty much verified by either TI internally or by the certification agency. So WMW is working voltage. It is really counting the long-term and the working voltage withstand capability.

And the RM is the repetitive peak voltage, which most of the time is 1.414 times of the working voltage. And most importantly, the degradation of the galvanic isolation depends normally on the peak voltage. And VIORM is the repetitive voltage of absolute envelope of voltage over time. So this one is this-- while these two values are tied together, the-- it matters with your long-term operation, it matters with your lifetime of the isolation barrier.

Another one is the surge voltage. Surge voltage is a type test only. So what is type test? Type test is not routine test which has been tested on every part in terms of the production. A type test is used for the certification, which the IEC, VDE, UL, they monitor the process of the manufacturer. So then, OK, in sampling test, it has been certified. It is not working for every part.

So where surge voltage is the highest instantaneous value of an isolation voltage pulse with short time duration and a specified waveform shape. So what is the goal? The goal is to handle the lightning strike. These are pretty high. So you are working with a 1.5 kV system, but your surge voltage can be over 10 kV. And that is what the majority of the systems require-- all the reinforced isolation working at least about surge voltage over 10 kV surge.

So 10 kV surge and 1 kV working, there's a long-- there's a large gap. And this just handles this very high-- short period. And in the certification, it is 1 pulse per second, you have been tested for 50 consecutive surge pulses. That is for certification .

Partial discharge. Partial discharge is majority is being used starting from the opto-coupler. And the goal is to verify the performance of the insulation between input and output-- the material or the mold compound by measuring the partial discharge level under a specified condition. And you can see here I show an equipment setup. The Ca is your device under test. You have bypassing capacitor, you have a partial discharge monitor Zm. And you also have some filter.

So the requirements-- under all of the [INAUDIBLE] that are going to be introduced, it has to be less than 5 picocoulombs. And how do we test-- and a partial discharge, there's a method a and method b1. So in method a, you can see here, it is having a charging profile. The charging profile is, OK, you start from 0, you ramping quickly to the VIOTM, which is we introduced before, for 60 seconds. And to simulate a current of the transient overvoltage.

And then it goes to your working voltage. The working-- comparative working voltage based on times with the F. F is a coefficient-- 1.6 for reinforced, 1.2 for basic, and for different subgroups that has been defined in the certification. So here the qpd is measuring the voltage. It's for 10 seconds. Over the 10 seconds, what is the total charge-- discharge right there?

Method b1 is-- the only difference is, OK, it's a routine test. You can compare with the method a is a certification test. Here it isn't-- method b1 is a routine test, which means every part going to make sure your partial discharge under method b1 is under 5 picocoulombs.

And you can see here the major difference, initial voltage only for 1 second. But you have a different coefficient under the VIORM, which is 1.875 for reinforced, 1.5 for VISO. I mean, if you see the F1, F2, F3, there are a lot of definitions right there. So I give you some information.

If you check the IEC 60664, that one, [INAUDIBLE] one is environment factor, another is hysteresis factor, another is safety factor, and also deviation factor from the normal voltage. So basically, it's been covering all of the machine requirement, temperature requirement, a lot of other requirements, to make sure, OK, you are make-- you are 100% tested to make sure that your working voltage is being tested with a working voltage with also additional market.

And we'll see the real-time, real-world waveform about how this is tested. I mean, here you go. You see the [INAUDIBLE] test. It starts from 0 ramping to VIOTM and then going to V2, which is your working voltage times the coefficient. So that's why you see in the standards or [INAUDIBLE] drawing a line either DC or AC.

So here is just throwing in an example to have you visibly see what is been tested in the real scenario. And the next parameter I want to introduce is the Time Dependent Dielectric Breakdown. As I mentioned before, only VDE has this parameter there. And the new released IEC for inductive and the capacitive also introduce the TDDB.

And what is TDDB? TDDB is an accelerated lifetime aging by testing the lifetime of the capacitive isolation in a very high voltage. Suppose in our datasheet it's 1.5 kV RMS. And but in order to reach to a certain [INAUDIBLE] range, you have to take the part really high to achieve the part-- I mean, you have-- for example, in here you have 5,000 volts, you have 6,000 volts, and you have 7,000 volts. So make sure you have certain multiple parts.

And then you recalculate your 1 ppm line. And then it goes to the 1.5 kV. You can see here, with 1.5 kV, if you go into the lifetime, it is over 100 years. The reason why we put 1.5 kV is pretty much limited by the environment, which is the packaging the isolation barrier is been [INAUDIBLE] into, because creepage distance for majority of the reinforced [INAUDIBLE] 80 millimeter creepage.

The 80 millimeter creepage by IEC standard can only handle maximum of 1.6 kV under basic isolation. So that is we're-- OK, how do we validate the lifetime? Where do we spec? And how do we make sure that the driver has been handling in a proper situation so that it can meet the lifetime requirements.

And if you see the majority of the TI isolator datasheets, all of them have this curve. And then which-- you can clearly tell all the drivers not only can handle high voltage for short moment, it can also handle your working voltage for a very long time. And that is only unique to TI. At this moment, I don't see any other competitors that's been showing this lifetime curve in their datasheet.

So the next one is the creepage distance and the clearance distance. So in the-- creepage distance is along the surface, clearance resistance is along the air. So what I'm thinking-- what I want to emphasize here is when it's coming to the surface, it matters with the pollution degree, the humidity, and the condensation matters.

But when it's going through the air through the-- for the clearance, the only thing that matters is air pressure. Oh, you are sitting in sea level or you are sitting at sea level plus 5,000 meters? And also, the temperature also matters.

So for each distance, it has been influenced for different parameters. And for creepage, it is tied to the RMS working voltage, tied to the pollution degree, tied to the surface material group. For clearance, it's tied to the temporary voltage, which is maybe high voltage transient, and also recurring peak voltage that is going through the air. And if you go into over 2,000 meters, there will be coefficient. For 5,000 meters, your coefficient at 1.48 which means at sea level you require 1 millimeter. But going 5,000 meters, you're going to require 1.48. That is the parameter influences, and also what it impacts.

Next one is material group and CTI. Material group is being dependent on the Comparative Index-- Tracking Index, CTI. And how do we [INAUDIBLE] CTI? For all the different information, please go to IEC 60112.

But here it's really testing the maximum voltage VAC. And which in insulation material withstands 50 drops per 30 seconds a drop to a contaminated water, which is having a certain kind of chemical residue. And you have to make sure no tracking less 0.5 amps. And it will be an accelerated simulation condition.

As you can see here, CTI larger than 600 is material group I. And CTI less than 175 is material group IIIb. So what I want to emphasize here, so the majority of TI servers is material group I. I mean, [INAUDIBLE] say 99% in current scenario.

But this is very high for the driver. The PCB which the driver has been sitting onto, 99% are material group IIIa, unless you have other very expensive PCB. Otherwise, the dominant PCB in the industry belongs to material group IIIa, so which means you have a very good, very solid driver, sitting on a low material group.

And who got to decide the creepage distance? It will not be the driver. It will be limited by the PCB to meet the creepage and clearance requirement. So pollution degree. So pollution degree, how-- I mean, what are pollution degree 1, 2, 3, 4 mean? Here I give you some examples.

In the pollution degree 1, is-- which means there's no conductive pollution. And the pollutant degree 2, where we are working in the office in the lab, you're going to see some occasional condensation, but it's very rare. And the pollution degree 3 is pretty much industrial and farming, not conductive pollution, but could become conductive due to expected compensation. Pollution degree 4 pretty much outdoor applications.

So you can see where-- why the server telecom and also for the automotive we pretty much apply the pollution degree 2. And that is a very dominant thing. For some occasional cases, industrial, it's working in pollution degree 3. For solar or some other which get exposed to very severe weather, you-- you're going to apply the pollution degree there.

And if you are thinking in a different, how to say, different locations of the office of the building, the impulse withstand voltage, or we call overvoltage category, also matters. I mean, if you're working on the category number 4, which is very close to the utility transformer, you've got to see the highest impulse voltage.

Category number 3 is pretty much your utility panel or distribution board. Category number 2 is outlets. It's where your phone gets charged, outlets within your home. So you have your phone adapter, laptop adapter, these are all go to the category number 2. That is, the majority of server telecom OBCs is being applied to, because it's being after the utility meter, it's being after the utility panel. That is the category number 2 is the majority of our equipment will be sitting at.

OK. So many parameters. How do these parameters get tested for the popular standard, which is IEC, VDE, are shown right here. So basically, all of this you have multiple groups. Every group supposed to handle either mechanical or thermal, or-- and creepage distance or lifetime. So every group has a purpose.

But all the groups-- most of the groups, like 1, 2, 3, they have a precondition. What are the four preconditions? [INAUDIBLE] method b1, RIO. Then they go through all the tests, then they measure RIO, measure-- for the group 1, 2, 3, they measure RIO, and also q-- partial discharge, Method a.

For group 4, they're testing the isolation resistance at a different temperature ratings. Subgroup number 5 is just measuring the creepage and then testing the flammability. For subgroup number 6, this is something I want to introduce. So only VDE-- only VDE-10 have it. IEC for the opto-couplers, it does not have it, because this is an end-of-lifetime test based on the high temperature, working with a time with a coefficient.

And VDE-10 is expired. Now we are all-- I mean, converting all this certification to the VDE-11. And the VDE-11 is officially put in the TDDB right there, as you can see right here. So at this moment, all the TI [INAUDIBLE] has been certified VDE, we have dash 11. If you see a VDE-10 there, we are updating the datasheet underway.

And the UL 1577. So this is a type test instead of routine test. And it is slightly different with the-- than the testing before. And you can see here this is not testing RIO. It's testing can the part handle-- withstand the voltage, VISO for 1 minute. Not for 1 second, 1 minute, because in the production, it's being tested 1.2 times the VISO for 1 second, and here it's testing for 1 minute. So then OK, there's no isolation breakdown.

For the double protection test, I want to tell you this is not double isolation. This is for certain application which the UL has been specified into. And so far, I have not seen any application which is using their parts for double protection test. These are very stringent tests. I mean, you have to test the part at 120 kV, 500 nanoseconds, 50 cycles, 5-second interval, no visible damage. So in this moment, double test is not what I've seen very popular. So the majority is still the VISO we have here on the left.

And it-- also for the left, as long as the VISO has been reaching a certain level, it still can be called reinforced isolation. That is the key message I would like to reinforce right here. So now, next page, we have-- we learned all the parameters, learned all of the standards. And going to the system, what are the complete system requirements?

Yes, if I'm building a converter, I want to make sure the components are good. I want to make sure that the component [INAUDIBLE] the PCB, which is the every system standard built from IEC 60664 have components in the system to make sure together go into the complete system requirements. So because of timing, I'm just giving an example for the telecom server. For other applications, it'll be similar.

And what is IEC 60664 been pretty much talking about? OK. It has been talking about a low volt system, which is up to 1.5 TDDB or 1,000 volts VAC like 30 kilohertz. It tells about the clearance and creepage distance under different voltage. It's also testing about electrical strength testing. You want to make sure you have-- the package-wise, they're good. The capability-wise, you are good.

So this is giving a guidance about the insulation requirements for majority of the end equipment. So this is the library. When you want to get something for your special equipment, you start from here. So this is a golden standard. And a lot of end equipment are references to [INAUDIBLE] from.

And then going to the IEC 60664, there are so many pages-- hundreds of pages. Which table matters the most? Table F1, F2, F4, and the correction factor, table A2. And we also show you how to do the electric strength test, either by ways that-- impulse testing or do partial discharge over working voltage. So you summarize the 100 pages of IEC 60664, all of them are talking about this. So if you understand this table, you're pretty much close to where these tables are telling you to.

And dimensioning CLR, you have two ways. You have basic isolation, and for the F2, a reinforced isolation for F2, but one step higher, which means, oh, yes, if I want to build a reinforced isolation, I look at F2 for 800 volts, then I go to one step higher.

And here it shows many steps. You have 300 volts up to 12,000 volts, so which means reinforced isolation is, just go one step higher. Not two times-- just one step higher. If you're 1.5 kV transient, you go to 2.5 kV. If you have 2.5 kV, you go to 4 kV. If you have 4 kV, you go to 6 kV. That's why the impulse voltage in the datasheet has been spec in [INAUDIBLE] overvoltage category 1, category 2, category 4.

And here is an example what I show in the server telecom system. If your output voltage is not higher than 60 volts, you-- and these 60 volts is-- we consider it SELV, which is safety extra low voltage-- tied to the ground. You do not need reinforced isolation. You do not need. You only need basic isolation. It's good enough.

And from the 60 volts to the 12 volts output, because your input is SELV, because the output is SELV, safety extra low voltage, you do not need reinforced isolation. For here, most of the time, function isolation will be good enough. That's why a lot of customers are building a non-iso converter even right here, back [INAUDIBLE]. And you do not need a full bridge, try to have more components and deal with the transformer.

So here has-- OK. You start from the SELV limit. And then you may has been lifting the equation here below. So it is-- SELV is 60 volts under the and 60 volts DC. And the TNV means Telecom Network Voltage. So if not counting about-- if it is under 60 volts, then you have SELV or telecom network voltage category 1.

If it's inside the building, you go to SELV, which is no-- if it's outside of the building, it is TNV 1. So if it is not SELV, then you go through hazardous voltage, which means you are pretty much about 120 volts. You go to [INAUDIBLE] voltage, hazardous voltage.

And in this, yes, you go to TNV 1/2 and [INAUDIBLE] TNV 3. If it's outside of the building, it is TNV 3. So this just tells you, OK, which voltage category. And why this voltage category matters? OK, here you go. Different voltage categories specify the IEC 60950, between each group the recommended-- the isolation grade has been specified.

And I put all of this table right here into the left-hand side table so that you can see, for function isolation, it only require between 2 safety extra low voltage, less than 60 volts brick module. For reinforced isolation, if you have a hazardous voltage, to any other voltage you need reinforced isolation. But if you are a 200-volt system, we need the TNV 2. To other TNV-1 or -3, you only need a basic isolation.

So I'm giving you all the examples right here. So then you know when functional [INAUDIBLE] is needed, when basic [INAUDIBLE] is needed, when reinforced [INAUDIBLE] is needed. So all of them are not coming from, oh, yeah, this has all been traced back to the standards or equipment. In each company we may have a few experts [INAUDIBLE] oh, yes, it has been tested basic. Or has been-- for Tens of years, it's always been reinforced. And no one even questions why reinforced is there. So here is the story which you can trace back to the fundamentals.

And yes, I've already discussed the IEC 60950 is talking about two things-- clearance, creepage, and also with the mains transient voltage. As you can see right here, based on different AC mains voltage-- for example, if you-- this is being line to neutral. Or if it is a single-point system, you have 120 volts, or in China, depending on-- 240 volts, you only add different overvoltage category, you're seeing the requirement is different.

So for example, if you are using a plug to your home, you only-- for basic isolation, you only need 1.5 kV surge. And you go to reinforced isolation, oh, you go one step higher, that's what you take out from this table. And also, for over the 150 volts, this is including the higher voltage. Then you can-- you're going to have a higher step.

So here, it means from 330 to 8 kV, it is all divided by different categories which I illustrate in the steps before. So you can see, OK, what are my parameters at voltage? What is my input? But in US, 120 volts. In other countries, we did 2-- with the fixed voltage over then 120, see here, up to 230, and you use a higher grade.

And next step is clearance. For peak working voltage, for example, and 420 volts, then you go-- if it is 1.5 kV transient, you only need 2 millimeters right here. And the value in the bracket applies based on the IEC 62368. This is a new standard replace the IEC 60950. So this is for clearance and creepage for functional isolation, basic.

For 400 volts, if you are working with a PCB with a material group IIIa, you need 4 millimeter. And for reinforced isolation, please times 2. And now people say, OK, I need a reinforced isolation or driver. Yes, here you go. You need 80 millimeter. But when it's coming to the pulsed voltage right here, it is not that high. I mean, sometimes we have a power which is pretty much, very much overkill.

So here I'm giving some example which we can see right here. So I have-- this is DC to DC my output voltage is not 60 volts. It's reaching to 75 volts. So 75 volts is not safety extra low voltage anymore. It is TNV circuit.

So [INAUDIBLE] going by primary, going to TNV circuit, yeah, look in the table. I need the reinforced isolation. And for this system-- I mean, the majority of the 40-volt batteries are below 60. And there are some very legacy telecoms with nominal-- not 48. It's nominal 60 volts. And then they're reaching to 75 volts.

But-- this from the market-wise, the dominant is still SELV, only to be compatible for some increments go to over 60 on the map is very rare. And then you go to the table. You go to find the table. What is this?

Oh. Sorry. Let me open the slides again. Collapsed. We are here. And let's resume.

So going to-- if you search the table, say OK, oh, yeah, I'm over category number 2. I need 2.5 kV transient. And my clearance 4 millimeter. At 5,000 meter, I need 6 millimeter because I need to times 1.48. And for the driver, yeah, you're pretty good. You have material group number 1, you only need only 4 millimeter. But when even the PCB needs to be times 2. And electrical strength test in the 3 kV VISO.

So here you go. You now know the which package I you need to choose, what kind of electrical strength can the driver have to meet with. So this is one example of-- that's why the majority of the popular systems that you see, oh, your wired voltage, 8 meters, and it has to handle 44, 42, 42, peak, which is 3 kV RMS.

And with that, I'm going to close the presentation with what TI has, what solution we are having now. So we have simple driver, does not have-- it is pretty much having the single channel, like all on the here. We also have-- this is a dual channel, sorry. It's 21, 520, 530, 540. And also, the 225 in the LGA package, 220 in narrow body package. They are all dual-channel driver with very basic UL protecting features.

We also have a single-channel driver, which are UCC53, which is CMOS input. We also have optical compatible input. It's still CMOS isolation, but it's optical compatible input. It is 2351X family. And it also has a lower isolation. 5 minutes 5 kV, 3 means 3 kV. So we can have here.

So these are all going to the simple drivers. Then single channel or dual channel. When you're doing a smart driver, they're all single channel. All of them have desat, ready, fault. And for the 217 family, it has one additional sensing channel, which is, you have analogue signal, you have temperature, voltage, current. And it can read in a signal with insulation barrier, gives you a PWM signal. You can either read duty cycle or through RC filter.

So 217 family gives you additional next-generation and the fast for optimized performance with additional integration for a [INAUDIBLE] drive and for high-voltage motor power. And for [INAUDIBLE] for IEBT. It's the next generation of ISO 5451.

UCC5870 is TI's first SUD compliant and ISO 20626 compliant, SPI with diagnostics, either 36-pin or DWJ package. That has been targeted for automotive traction drive.

With that, I think it's time for-- thank you very much for your time. And we can spend the next 10 minutes, I want to say 12 minutes, discussing the questions. Let me see what I've got. Let me-- And here is the final page. And let me see what question I got. Give me a second.

I'll get out of this. See what questions I got. OK. We do get a few questions. Let me see-- let me understand it.

OK. And the second-- one question is very interesting. What is a system [INAUDIBLE] standard for automotive application? So we-- firstly, this presentation is part of presentation I'm submitting for APEC 2021. So in June-- I remember, in June I'm giving a three-hour presentation for all of the industry, discussing about server telecom, also discussing about the automotive.

And the automotive, at this moment there's no one standard, based on my experience. And most of them is using IEC 60663. So that is what I can tell. Another question is, how-- what can I use to achieve higher voltage isolation, like 3.5 kV? Is it not DC voltage, it's a pulsed voltage.

So what I can illustrate right here is the-- the majority of TI drivers, if you go to-- just for example, in this table, you can see right here. We have 58 family, this is high 1.5 kV, reinforced isolation. And this is what I'm [INAUDIBLE] here, information shown in here is working voltage.

But let's see 5870. 3.7 kV is not working voltage. This one is VISO, has been spec'd in the datasheet. Another information I can tell is to read this table here. So that's why-- I mean, there are different parameters.

If you want to handle-- to answer your question, if you want to handle 3.5 kV pulse voltage, the majority of our drivers, even narrow body, 4 millimeter, can handle 42, 42 peak. Wire voltage can handle 80 voltage peak. So I don't-- I think that you can read in the VIOTM in the datasheet, you will find the right answer.

Another question coming from Bernard Atkins, slide number 17. Let me go to page 17. Is this profile for instantaneous DC voltage? Yes. Yeah, it is-- this-- I mean, this is a profile. I [INAUDIBLE] for 60 seconds.

And it is for peak-- I mean, for the frequencies [INAUDIBLE] frequency. It is frequency of 60 hertz. And yeah, when we are talking about VIOTM, VIOTM is the peak voltage. If you can go to the definition of VIOTM-- So the working voting and VIOTM. VIOTM is a peak value. VISO is RMS voltage.

I see a few other question is asking. Let me see. We have 7 minutes. But I wish that answered your question. We can talk offline. Another one is, do we need to consider AC transient plus overvoltage on the secondary side?

Oh, I know what you're talking about. You're talking about [INAUDIBLE] system. This is a long story. I have 20 more pages discussing that in the APEC. So please, join APEC this year.

And I can give some quick answer, is-- we need transient for inducing 25 volts plus 75 volts. So you discussed about a 2.25 kV plus 75. Let me give you-- it is not 25. If you're testing your every equipment, you get 10% discount. So that's why it has 2250-- 2.25. If you look into the brick module, the datasheet will say, I'm 2.25 kV.

The reason is [INAUDIBLE] 2.5 kV is being tested with a-- for every mod, you get 10% discount. That is 2.25 kV. And to evaluate this one, you have two ways. Method one is for transient voltage. Another one is partial discharge test, which is based on working voltage. We have two ways to tell it. And all of this will be discussed in another presentation. It's a very good question.

Is there any possibility of service resonance because of some presented inductance? Very good question. The answer is yes, if talking about immune-- we did an immunity test. And we have collaterals to support that. And TI is doing extensive amount of tests.

We're talking-- we are planning, for example, we have GND one on the left, we have GND one on the right. And we apply a very high-frequency [INAUDIBLE] 1 gigahertz. By switching the voltage peak from left to right, and to try to understand what is the internal resonance, which is we have discussed in the [INAUDIBLE] conducted or radiated immunity.

Because if you go into the internal-- go to capacitor and transformer, they've all been developed in the OOK-- how to say-- in the on-off canyon. And that is pretty much for the competitor. Because to find a signal, you can only apply high frequency. And then a high frequency is roughly from 500 megahertz to a few gigahertz. Different [INAUDIBLE] different manufacturer has been reaching at different times.

But when you are going there, you're going to see some kind of a noise being coupled. But that's why you have a differential amplifier, which is, you go to this page, you have two differential pairs. And this has been designed to prolong any noise from left to right on the common mode. So because when you have [INAUDIBLE] noises, pretty much common mode. So we have very good performance there, too. Very good question.

Another question-- how do-- How do I arrive at VISO for system working voltage? How to arrive at VISO for system-- I don't quite understand what "arrive" means. [INAUDIBLE] pros and cons [INAUDIBLE] design with-- oh, what could be the pros and cons if we replace an existing design with isolated gate drivers?

OK. Firstly I'll discuss in the cons. Cons is, yeah, the iso driver is relatively more expensive than non-iso driver, because it's involving two lines, It's involving more bounding wires. It's involving putting the die in the chip. it's all labor related. So all of this coming to assembly cost.

So the cons, it's a little bit more expensive. But talking to the TI, [INAUDIBLE] you go overseas with more vendors, more competitors coming to market, you know, iso driver has been a standard for high-performance converters. Everyone uses iso drivers to achieve Higher performance, better skew, higher CMTI.

And what I can find now, for everything [INAUDIBLE] gallium nitride, they're all using-- they all use iso drivers because of the performance. And for high frequency, you do not use opto, because the jitter-- the jitter, the pulse distortion, the degradation of the LED, it all suffers a lot. So a lot of advantages. We TI have a lot of collateral supporting them, too.