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Engineer It: When to use a pre-driver vs. an integrated motor
工程设计： 何时使用预驱动器，何时使用集成电机
What is the difference between a pre-driver and an integrated motor driver and how do you choose one over the other?
前置驱动器和集成电机驱动器有什么区别，以及如何取舍？
Think it , Design it, Engineer it.
大家好，我是德州仪器集成电机驱动产品市场经理 Michael Firth。今天，我从基尔比电机实验室来到这里。这里是我们进行电机控制算法高级研发的地方。我今天想花一点时间谈谈预驱动器与集成电机驱动器。它们的主要区别是什么？首先，让我们来看看两种不同架构的框图。
Hello, I'm Michael Firth, Product Marketing Manager for Texas Instruments, Integrated Motor Drive Products. And today, I'm coming to you from Kilby Motor Labs. This is where we do our advanced R&D for motor control algorithms. I'd like to spend a little time today talking about a pre driver versus an integrated motor driver. What are the major differences, and when would you select one versus the other. So to start, let's take a look at the block diagrams of the two different architectures.
因此，你在顶部看到的就是预驱动器。实际上，我这里有一个前置驱动器的例子。这是 DRV8301。
So what you see here at the top is a pre driver. I've actually got here an example of a pre driver. This is the DRV8301.
DRV8301 上集成了电流检测控制、逻辑和一些电源管理功能，但没有任何场效应晶体管。这就是前置驱动器与集成驱动器的主要区别。场效应晶体管是外部的。外部的场效应管有很多不同的优势。
And when you look at a pre driver, what you've got on the DRV8301 is integrated, current sense control, logic, some power management, but you don't have any of the FETs. And that's the major distinction with a pre driver versus an integrated driver. The FETs are external. Having the FETs external gives you a lot of different advantages.
你可以看到这里有六个独立的场效应管。这是很大的一块电路板空间，从散热角度来看不错。不过，就散热性能而言，这些场效应晶体管的低 RDS（on）才是最大的亮点。集成式解决方案的 RDS(on) 值根本无法与使用分立式预驱动器的 RDS(on) 值相比。说到集成，让我们来看看集成解决方案。这是 DRV8312，你可以看到它的体积要小得多，也干净得多。
You can see here you've got the six individual FETs. It's quite a bit of board space, which is nice from a thermal perspective. But really, the biggest bang for the buck in terms of thermal performance is the low RDS(on)s of these FETs. You just simply can't get the levels of RDS(on) with an integrated solution that you can get with a pre driver with discretes. So speaking of integrated, let's take a look at an integrated solution. This here is the DRV8312, and you can see that it's much, much smaller, much cleaner.
FET 实际上集成在这个器件中。它有 110 毫欧的场效应晶体管，电路板空间小得多，但就电流能力而言，与预驱动器相比，它的能力相当有限。
The FETs are actually integrated in this device. It's got 110 milliohm FETs, much smaller board space, but in terms of current capability, it's quite limited versus a pre driver.
因此，就选择前置驱动器的优势而言，基本上是由于热性能和电流要求。电流大得多，性能和散热就好得多。对于集成驱动器，如果你需要尽可能小的设计，就会选择集成驱动器。就电路板空间而言，它们非常小。就所有场效应管而言，它们也非常容易安装和设计，一切都已安排妥当。说到散热性能，让我们来看看这两款器件在相同条件下的性能对比。
So in terms of the advantages why you'd pick a pre driver, it basically is due to thermal performance and current requirements. Much higher current, much better performance and thermals. For an integrated driver, you pick that if you need the smallest possible design. They're very small in terms of board space. They're also very easy to drop in and design, in terms of all the FETs and everything's taken care of. So speaking of thermal performance, let's take a look and see how these two devices compare when running identical conditions.
在这里，我们使用了热像仪，并运行了我刚才向大家展示的两款 EVM，电机负载相似。其中一个是带有 110 毫欧集成 FET 的 DRV8312，运行温度为 139 摄氏度。电压为 24 伏，有效值为 3.5 安培。对于大多数客户的设计来说，139 摄氏度是无法接受的。温度太高了。请看带有外部 FET 的 DRV8301 前置驱动器。它的最高运行温度为 37 摄氏度。这也是为什么要选择前置驱动器而不是集成驱动器的原因。
So here we've taken a thermal camera and we've run both of those EVMs that I just showed you, similar motor loads. One, the DRV8312 with 110 milliohm integrated FETs, is running at 139 degrees C. This is at 24 volts, 3 and 1/2 amps RMS. 139 degrees C is not going to be acceptable for most customer designs. It's just running too hot. Take a look at that pre driver, the DRV8301 with the external FETs. That's running at a maximum temperature of 37 degrees C. So much, much cooler. And again, that's why you're going to pick a pre driver over an integrated driver.
让我们再来看看一组热图像。这是 DRV8711。这是一个预驱动器，但不是三相无刷，实际上是一个双极步进预驱动器。在这个例子中，我们使用的是 24 伏电压，两个不同的电流，一个峰值为 3 安培，另一个峰值为 9 安培。你可以清楚地看到，在温度性能方面，它的表现非常出色。前置驱动器 3 安培，53 摄氏度。这是最高温度。9 安培时，场效应管的最高温度为 60 摄氏度。因此，6 安培的电流增加了 7 摄氏度。
Let's take a look at one more set of thermal images. This is off of the DRV8711. This is a pre driver, but instead of being a three phase brushless, it's actually a bipolar stepper pre driver. And in this example, we're running at 24 volts, two different currents, one at 3 amp peak, and the other at 9 amp peak. And you can clearly see here, in terms of temperature performance, it's spectacular. 3 amps, 53 degrees C, on the pre driver. That's the maximum temperature. At 9 amps, the maximum temperature is on the FETs, that's 60 degrees C. So that's a 7 degree basic delta for a 6 amp increase.
同样，这也是采用真正低 RDS(on) FET 的地方。它们能真正发挥作用，对热性能有很大帮助。总之，在考虑前置驱动器和集成驱动器时，要考虑设计的热性能要求。如果您需要大电流和出色的热性能，那么您可以选择前置驱动器。如果您需要尽可能小的电路板空间和最简单的设计，请考虑集成电机驱动器。感谢您抽出时间观看本视频。如果您有任何问题，请参阅以下网址。
Again, that's where you get the really low RDS(on) FETs. They really kick in and they really help with the thermal performance. So in summary, when considering a pre driver versus an integrated driver, consider the thermal performance requirements of the design. If you need high current with excellent thermal performance, the pre driver is your choice. If you're looking for the smallest board space possible, simplest design, take a look at integrated motor drivers. I'd like to thank you for taking the time to watch this video. And if you have any questions, please see the following URLs.
参考：
Engineer It: When to use a pre-driver vs. an integrated motor | Video | TI.com
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