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Good morning and good afternoon, everyone. My name is [INAUDIBLE] Patel. I'm a systems engineer for eFuse products with the TI power switches crew. Today, I'll be presenting to you about the innovative solutions using eFuses to solve power density challenges in input power protection and power MUXing applications.

During the session, we'll go over the input power protection and power MUXing requirements in common applications, what are the different fault scenarios and the need for power protection and MUXing. We'll look at a few existing solutions and the associated power density challenges and how we can overcome them using TI eFuses, including the latest back-to-back eFuse portfolio the true reverse current blocking, and how it helps to come up with flexible and scalable solutions to provide solutions for different applications. We'll have a few end equipment examples to see how these eFuses can be used to implement power MUXing solutions. And at the end of the session, we'll have time to address a few questions.

So let's start off by looking at the use of power switches in a typical application. Any application requires power, and power switches are commonly used whenever there is a need to provide some sort of control or protection on the power path. There are different types of power switches solutions available from Texas Instruments, and each of these power switches have a different set of features and functionality based on where they are used. For example, if you're using a power switch on the input side, you'll be looking at devices like the ideal diode, or ORing controllers, or hot swap controllers, or eFuses.

If you are using them on the board to provide power management for different subsystems, you'll be using load switch products. If you are using it to drive power to an external load which is inductive in nature, you'll be using a high side switch. For the focus of today's presentation, we'll be using, or trying to look at the power MUXing solutions which are used on the input side to switch between different powers and also provide protection.

So let's start off by looking at what kind of power MUXing solutions are available. Power MUXing is used in an application whenever you need to select between more than one input power source which is used to deliver power to the load. This may be needed for the sake of redundancy or providing backup power. And here are some of the key requirements you would like to focus on when selecting a power MUXing solution.

Firstly, the solution should not introduce any additional loss in the power path. Then it should prevent any kind of cross current flow between the two power sources. Next, it should be able to provide seamless and fast switch-over between the two power sources, so that if there is a power supply switch-over during normal operation, there is minimal droop at the output side, and it allows the load to continue functioning without any interruption. In some application, you may also would like to have automatic or manual control over the switch-over, and it's also preferable to have some sort of indication to say which of the available power sources is being used at the moment.

If you look at available solutions for power MUXing and ORing, there are a few solutions you can look at. The first and most simple solution is using discrete diodes. This is a commonly-used solution, especially for low currents. This solution can be very simple to implement, and it has certain benefits, in terms of the protection it offers, especially on the input side, against reverse current and reverse polarity, and it works well for low currents.

But on the downside, it has a higher voltage drop and also adds excess power consumption, especially when used at higher currents. It also doesn't provide any form of protection in the forward direction, for example, against over voltage, or current short circuits, or excessive inrush current. So this kind of solution is good for low-current applications. But as we go increasing the current requirements, it becomes bigger and bulkier.

An alternative solution would be to use MOSFETs in place of diodes. The benefit of using a MOSFET is that it eliminates the forward drop which is associated with the diode when the FET is fully on. This makes it a better solution when used for higher currents.

But at the same time, it has a few drawbacks as well. It doesn't provide any form of device current blocking when it is in on state, and hence it cannot be used in case of ORing applications. Also, it doesn't inherently have any protection that needs to be implemented using additional discrete circuitry. But when it comes to higher currents, MOSFET-based solutions can be a better and more power efficient solution, as compared to diodes.

Then moving onto the integrated solutions which are available from Texas Instruments, we have devices like the TPS2116 and the TPS2120 and 2121, which are integrated powerMUX devices. The 2116 can operate up to 5.5 volts and handle up to 2.5 amps of current with the integrated power MOSFETS. It also has protection, such as soft start, as well as thermal shutdown, and it is available in a very small footprint, making it the most compact solution for low-voltage applications.

If the application demands higher voltage and higher current, the TPS2120 and TPS2121 are available. These devices can work up to 22 volts and handle up to 4 amps of current. They provide integrated ORing and MUXing, along with additional protection functions, such as soft start control for inrush current management as well as overvoltage, current limit, and thermal shutdown protection. So the integrated powerMUX solutions can provide a very compact and easy-to-use solution for two-channel power MUXing applications.

If you look at the different end equipments and different applications, the power MUXing requirements can be quite different. A few examples here show that different end equipments have different voltage requirements, as well as different current requirements. And in some cases, the number of channels between which the power MUXing needs to be done can also be different. Apart from that, each application may have specific functions or specs or certification requirements which can be different, and hence there is no single solution which can meet the need of all the end applications with a single integrated solution.

So let's look at another key aspect when it comes to power MUXing is the need for power path protection. So most applications, the key functions we expect are the system to be completely reliable, safe, and also it would be having minimum downtime. So there can be faults in the power path which we commonly encounter. For example, on the load side, there can be a short circuit or kind of overload. Or on the source side, there can be an overvoltage. So the system needs to be protected against these kind of faults.

There are certain applications which have additional protection needs, for example surge and EFT kind of transient on the power line, as well as reverse polarity and reverse current protection. The need of having the protection is to ensure that the system doesn't get damaged, the system is always safe and reliable, and the system has minimum down time.

When it comes to providing power path protection, eFuses are most often the best solutions you can find. eFuses are devices which have integrated power MOSFET current sense, along with some control circuitry, which provides active protection to the circuits by replacing commonly-used solutions, such as fuses and PTCs. eFuses prevent failure of the system during hot-plug or hop-swap events, as well as during steady state, by protecting against undervoltage, overvoltage, overcurrent, inrush, and other system fault events.

The key benefits of using an eFuse are that they save space by reducing the number of discrete components which are needed. And also, eFuses help to bring the solution faster to the market by providing a plug and play solution which often comes pre-certified from labs such as UL and IEC, which allows the end equipment to have less stringent certification requirements and testing, thereby being able to release the solution to the market faster. TI has a very wide portfolio of eFuse devices to cater to different end equipment needs at different voltage levels, current levels, and the type of protection functions they offer.

Now let me introduce you to a new device which was introduced by Texas Instruments this year. The TPS25947 is a 23-volt eFuse which can handle 5.5 amps current with integrated back-to-back eFuses with a total on resistance of 28.3 milliohm. The TPS25947 offers all sorts of protection inside the device, which includes overvoltage, overcurrent, short circuit, and overtemperature protection. It has adjustability on all these parameters. It also provides integrated current limit and monitoring functions up to 6 amp.

One of the key benefits of the TPS25947 is it uses the back-to-back FETs to provide true reverse current blocking with 0 DC reverse current at all times. And also, this is one of the first eFuses in the space to provide input reverse polarity protection without the need for any additional components. The TPS25947 is available in a space-saving 2 mm cross 2 mm QFN package. The TPS25947 is also planned for certification from UL and IEC, which will be available shortly. There are many applications in which the TPS25947 can be used. It includes adapter input protection or any form of power MUXing or ORing requirements, as well as a variety of other end equipments in the enterprise, communication, industrial, and personal electronic space.

Just for comparison, an equivalent discrete solution which offers all the same protection functions would look like this. So this would occupy a large board space and need a lot of different discrete components. The [INAUDIBLE] components would also mean a lower reliability of the solution, and also it doesn't provide, necessarily, all the protection functions which are needed in the application. The benefit of using an integrated eFuse like the TPS25947 is that it replaces all of this discrete circuitry in a single spacing component and needs very minimum passive components around it to make it work. And also, by virtue of being integrated, it is a more reliable solution, it is easier to use, and it helps in minimizing the overall solution size and cost and helps to bring the solution to market faster.

Now, let's look at how the TPS25947 can be used to implement different types of power MUXing configurations in innovative and scalable manner. So the first example I'm going to show you is implementing a 2-input priority power MUX using two TPS25947 devices. This solution can work up to 23-volt power supply rails and handle up to 5.5 amps of current on each frame.

So in this diagram, I'm showing the two supply rails, the primary rail and the auxiliary rail. And in each of these power path, we have one TPS25947 device, and the output of the eFuses are connected together to deliver power to the load. In this configuration, the TPS25947 allows you to provide automatic switch-over between these two power supplies where the user can adjust the threshold at which the switch-over happens. The switch-over will be very fast to ensure that there is a minimum output supply droop.

The device will also provide a digital indication which shows the system which of the two power supplies is available and active at any given point of time. Apart from power MUXing, the eFuse also provides a robust protection for the supplies, as well as the load, again, system faults such as undervoltage, overvoltage, and input reverse polarity. It provides inverse current limiting, as well as it provides two reverse current blocking to ensure there is no cross current flowing between the two supply rails.

So this is one of the many configurations which are possible using the two 947 devices which are shown in the device data sheet. There are a few other possible variations to this circuit, depending on the system needs. So we have one version of the circuit which allows you to provide overvoltage protection on the AUX rail, as well, by adding an additional signal FET. There can be another solution in which the switch-over time is traded off for the quiescent current, and another solution which provides circuit breaker action instead of current limiting. So all of these are possible using the TPS25947.