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[TEXAS INSTRUMENTS JINGLE]

Hello. In this video, I'm going to be discussing an automotive 48 volt mild hybrid electric vehicle power solution using the LM5164-Q1, a 100 volt buck converter, and the LM5180, a primary side regulated flyback converter. And before we get into the board and the demo, let's talk about mild hybrid electric vehicles.

So mild hybrid electric vehicle is right in the middle between a typical car and a hybrid electric vehicle. So a typical car with just an engine and a 12 volt battery will be the least expensive, but you'll have the worst fuel economy. A hybrid electric vehicle adds a big motor and a high voltage battery. So this will be the most expensive, but you'll have the best fuel economy of the three options.

A mild hybrid electric vehicle isn't too much more expensive, and you get better fuel economy because you're just adding a smaller motor and a 48 volt battery. This power solution utilizes the 12 volt battery and the 48 volt battery to create a 12 volt redundant power supply for the electronics inside of the vehicle. Let's get into some of the design features of this board.

First, the board supports the 12 volt and 48 volt dual battery power architecture that I mentioned earlier. It's also EMI-compliant and meets CISPR 25 Class 5 standards. This is easy to use, and is a compact and thermally optimized design. It has low quiescent current. It is AEC-Q100 Grade 1 Qualified, and the ambient temperature has a range of minus 40 degrees C all the way up to 125 degrees C.

Let's look at the block diagram and explain how these parts fit into the system. So we can see on our block diagram, we have our 48 volt battery. This goes into our non-isolated DC to DC power supply. This is the LM5164-Q1, which is rated to 100 volts to deal with the line transients from the 48 volt battery. The LM5164 also has low quiescent current, a small solution size, reduced complexity and EMI meeting the CISPR 25 Class 5 standards. This takes the 48 volt input and generates a 12.8 volt output for the electronics in the car.

The other battery-- the 12 volt battery-- goes through some reverse polarity protection, and then goes into the isolated DC to DC power supply, which is our LM5180-Q1, our primary side regulated flyback. This chip has simplified implementation, reduced BOM, and EMI meeting CISPR 25 Class 5 as well. It also has load regulation to plus or minus 1%, which is great for a PSR flyback. This provides isolation from the 48 volt transients, which can go up to 100 volts. This takes the 12 volt battery input and generates a 5 volt output and a 12.2 volt output.

The reason we have 12.8 here and 12.2 here is because we want the power to be drawn from the 48 volt battery when both batteries are connected. When the 48 volt battery is disconnected or if it dies, we have our 12.2 volts as a backup. So now that we've seen the block diagram, let's take a look at the board and see how it relates. So this is the 48 volt input. This is the 100 volt buck, the LM5164-Q1. Here is the diode connection to the 12 volt output.

Over here, we have the 12 volt input from the 12 volt battery. This goes to the primary side regulated flyback. This goes to the isolation transformer, which has the 5 volt output and the 12 volt output. Right now in the setup, we have the 48 volt input, which is to emulate the 48 volt battery, and our 12 volt input to emulate our 12 volt battery.

We also have the current in from the 48 volt supply, and the current from the 12 volt supply. We also have the output current from the 12 volt output, as well as the 12 volt output after that diode connection. You can also see that 12 volt output here, and that output current here. You can also see the 5 volt output.

For the first demo, both batteries are connected. 48 volt is on and 12 volt is on. The 48 volt battery is supplying the majority of the current, and we're regulating to 12.8 volts. If we disconnect the 48 volt battery, we'll see this current be pulled from the 12 volt battery, and we'll regulate to about 12.2. So let's see what happens when we do that. So we've turned off the 48 volt battery. We have no current coming from the 48 volt battery, and now the entirety of the current is coming from the 12 volt battery. And we're regulating to 12.15 volts, and we see that drop on the scope.

So that's the first demo. The second demo I want to show is the load regulation for the primary side regulated flyback. If I turn on my load sweeper, we can see the load is sweeping from the maximum 200 milliamps down to a light load of about 15 milliamps. And we can see the 12 volt regulated output isn't changing a lot. We can see the actual values here on our load. We go down to about 12.15 and up to about 12.25. So this is plus 1/2 a percent minus 1/2 a percent, which is great regulation considering this is a primary side regulated flyback.

The next demo I want to show is the quiescent current for that 100 volt buck, the LM5164. So I'll stop the sweeper. We turn the buck converter back on. We turn off the 12 volts. We turn off the load. Now we're just seeing the current from the 48 volt battery through that 100 volt buck converter, and we have 12.7 volts regulated.

If we disconnect the load entirely, we can see the true quiescent current, since this is taking some current. If I unplug the electronic load, you can see that we're still regulating, and we have a quiescent current of about 60 micro amps, which is very good considering this is going from 48 volts down to 12.

So those are the three demos, and now you've seen the automotive 48 volt mild hybrid electric vehicle power solution. It meets all the specs and has low quiescent current, reduced complexity, small solution size, and it meets CISPR 25 Class 5. For more information, you can go to ti.com/LM5164-Q1 for the 100 volt buck, and ti.com/LM5180-Q1 for the primary side regulated flyback. Thank you for watching.