Understand the characteristics of IPDs and make effective use of them | Infineon Technologies Technical Column

An IPD is a packaged power control device. The output section contains power devices (devices that perform power conversion) such as MOS FETS and IGBTS, and the control circuitry that controls these devices is made up of a single chip or multiple chips.
IPD is an abbreviation for "Intelligent Power Device," and depending on the manufacturer it may also be called a "Smart SWITCHES" or "High-side/Low-side SWITCHES." This is because IPDs have the function of a power SWITCHES that turns the flow of current on and off.
A loose translation of "IPD" is "intelligent power control device," which indicates that it is a control device that has self-protection functions and can safely process electrical energy.
IPDs also have the ability to notify microcontrollers (small computers) of abnormal conditions, making it possible to analyze any problems that may occur.

IPD self-protection function
IPDs have a function to prevent electrical problems, which is called a "self-protection function." If too much current flows through the electronic circuit or SWITCHES temperature becomes too high, the protection circuit will automatically activate. This makes it possible to cut off the current and prevent overheating, preventing damage to the IPD itself.

IPD power control
IPDs have a control function that can absorb and safely process the electrical energy that is generated when SWITCHES is turned off. For example, even if an electrical SWITCHES breaks and current flows in a direction different from the intended direction, the IPD will not break down and will continue to function as SWITCHES. This is possible thanks to this control function.

As we have already explained, IPDs are a type of semiconductor SWITCHES. However, there are significant differences in the functionality of IPDs compared to MOS FETS alone, which are also semiconductor SWITCHES. If the load in MOS FETS circuit is shorted, MOS FETS itself may be damaged, leading to failure.
However, IPDs have built-in protection circuits and circuits that absorb electrical energy, so they are not damaged even if a short circuit occurs and can still function as SWITCHES. Let's compare them with FUSES, which prevent excessive current from flowing.
FUSES has the characteristic of physically cutting off the flow of current at the expense of itself when a large current flows in. Therefore, when a problem occurs, FUSES must be replaced to restore operation. On the other hand, when an IPD is used as a semiconductor FUSES, it detects abnormalities such as overcurrent and cuts off the flow of current. This self-protection function prevents damage to the IPD, so there is no need to replace it. Next, what about when used as SEMICONDUCTOR RELAYS to switch electrical circuits on and off?
For example, let's compare it with a mechanical relay. First, a mechanical relay has the characteristic of switching ON/OFF using mechanical contacts. Because it operates physically, there are some concerns about the lifespan and reliability of SWITCHES part. However, IPDs have no mechanical contacts. Unlike devices that operate physically, there is less risk of them breaking.
Furthermore, while mechanical relays make mechanical noise during operation, IPDs are quiet and do not produce any such noise. These characteristics make IPDs SEMICONDUCTOR RELAYS that has a long lifespan, high reliability, and is quiet.
Despite these features, IPDs are small and lightweight, and can also be mounted using reflow soldering, making mounting defects less likely to occur.
IPDs have a variety of features and are easy to use, making them widely used in situations where high safety and accuracy are required, such as the following:

While there are many benefits to using IPDs, there are also some disadvantages. One of the disadvantages is cost. Because IPDs are semiconductors, they tend to be more expensive than mechanical relays and mechanical FUSES, which are not. However, there are probably not many cases where all of the functions of an IPD are required. Costs can be reduced by selecting only the functions you need and narrowing down your selection to IPDs that have those functions.
Also, by creating reusable blocks at the design stage, costs can ultimately be reduced. Next is the design man-hours. Compared to the mechanical components mentioned above, the design man-hours can be greater. This is because IPDs have complex internal structures, and although the basic function is SWITCHES, additional functions are incorporated, so the design and integration of these functions takes man-hours.
Additionally, evaluation tests are required to ensure that each block functions correctly. This requires a lot of work, which can result in a large amount of work overall. However, the more effort you put in, the more advanced functionality you can ensure, which further increases reliability. As a result, it can be said that this is not a major disadvantage. Finally, I would like to talk about the risk of loss of control. While the protection function works against overcurrent, it does not work against the rated current. Therefore, depending on the circuit on the output side of the IPD, there is a risk of loss of control.
However, there is a way to mitigate this risk: by using a circuit called an active clamp.
An active clamp is a circuit that absorbs the "reverse electrical force" that occurs when SWITCHES is turned off and redirects it in the correct direction, preventing damage to SWITCHES. This function reduces the risk SWITCHES operating in an unexpected manner.
There are some disadvantages to IPD, but please understand that there are ways to deal with all of them, so they are not particularly big problems.