I was randomly talking to chatgpt about how I have been feeling burdened by having to make my own BLDC motor controllers for my robot lately and it randomly mentioned integrated half-bridge power modules as something I could use to cut down on my labor load in making these motor controllers. This immediately stood out to me as something I'd never heard of and something intriguing. I have so far been working on my lowside switch and highside switch which together form a half bridge. Many solder connections have been involved and alot of discrete components are involved. The concept of an integrated half bridge on a single chip - meaning two big power mosfets and all the drive circuitry for those power mosfets all condensed into a single chip would be a huge reduction in size and component count as well. So I researched if any are able to do 8v 30a for my 2430 BLDC motor's needs. Turns out there are some out there. At first I was looking at Texas Instruments CSD95377Q4M Half‑Bridge Driver (30 A) which can do 30a continuous so perfect for me. However, I didn't want to lock myself into a single vendor chip that may one day be discontinued. I prefer something ubiquitous with many competitors making it that can be purchased from aliexpress. Something commodity level. This way I future proof it and don't have to worry about any one manufacturer discontinuing parts I'm using and prices soaring because of that or simply the part becoming unavailable. So after a bit further digging I found CSD95481RWJ QFN chipset on aliexpress sold by several vendors and one was under $1 each. So it is equivalent to two power mosfets plus all drive circuitry for each power mosfet all for under $1. This one also has 60a continuous rating. It is only 5mm x 6mm in size which to me is insane. This is so much smaller than the setup I've been working on yet just as powerful. They are usually used for tiny buck converters and used directly on videocard PCBs and in servers and in automotive PCBs and much more. In any case, using 3 of these half bridge chips you can drive a BLDC motor. The consolidation of so many parts into such a tiny package is truly blowing my mind. So I ordered 60 of these chips - enough to drive 20 BLDC motors. I am leaning toward using these for all my motor controllers if working with them is easier than working with discrete components like I have been. They are cheaper to work with I think - I'd have to run the numbers on that though. They even have built in temp sensing we can read in which is a bonus. Their built in current sensing will not work for BLDC motors so I'll still need my shunt resistor current sensing circuit setup external to it but that's ok. All in all these appear to be a game changer in terms of reducing part count so less potential points of failure and also reducing board footprint so miniaturizing my electronics even more which is very good for us. I'm still needing to work out now how I want to hook these up in terms of PCB making for it and any discrete external components needed to support it. It is also top cooled which is interesting. I'm envisioning using silicone thermal adhesive to glue on a copper pad that has my braided solder wick wires already soldered to it. These will carry the heat away to my water cooled pipe system.







I'm kind of amazed that nobody really seems to use these for BLDC motor controllers. They seem perfect for it. Maybe I'll start a trend. Assuming I don't find out the hard way why they are never used for this application!



note: the full product title: "(5pcs)100% original New CSD95481RWJ 95481RWJ CSD59950RWJ 59950RWJ QFN Chipset"



note: for my previous BLDC motor controller design I was needing to use 6 digital IO pins to drive a single BLDC motor controller's 6 power mosfets by way of their control circuitry. But for a BLDC motor controller design using 3 CSD95481RWJ H-bridge chips, I will only need to use 3 digital IO pins on the microcontroller. These CSD95481RWJ H-bridge chips use a pwm pin that is a tri-state pin - you can have high, low, and floating as the signal you send to it from your microcontroller. Digital output high and low are the usual digital output modes but the floating mode you do in your code by configuring the pin to be a digital input pin which makes it a floating pin. These 3 states fed into the chip makes it either give you V+ as its output or V- as its output or just off/floating as its output. This corresponds perfectly to the normal h-bridge 3 states we'd be using with our discrete components previous microcontroller design. So this savings in total digital I/O pin usage on the microcontroller means you can drive more motors per microcontroller in theory which is pretty cool.