SMPS or Linear transformer for class 2 power supply

Thread Starter

wongwong

Joined Sep 12, 2021
4
Hi All,

I'm gonna build a PWM motor controller and power supply for the motor.

The motor power is 24Vdc and 1.8A (40W)

The power supply is required to be class 2 and whole product will apply for UL.

I'm not sure which brand and which model PMIC I should take for the SMPS

So what should I take for the Power supply? SMPS or Linear transformer?

if SMPS, can introduce some brand to me? Thanks!
 

Thread Starter

wongwong

Joined Sep 12, 2021
4
I mean I need to develop those power supply myself. I hope receive from you what kind of power supply I should go for?

Thanks all!
 

Irving

Joined Jan 30, 2016
2,311
I mean I need to develop those power supply myself. I hope receive from you what kind of power supply I should go for?

Thanks all!
Why do you need to develop it yourself? You already mentioned the need for UL certification. How many have you designed/built already? None from your questions. How long will you take to do this? From experience, if you get there in a year and half a dozen prototypes you'll be doing exceptionally well. Better to buy in a certified supply, or, if you must build it yourself for customisation or embedding reasons, licence in a design from someone like Meanwell and work with them.

Same with motor controller...
 

Papabravo

Joined Feb 24, 2006
17,277
Getting a UL certification is expensive. Maintaining that certification is like buying a subscription to a very expensive magazine that you'll never read, and you need to renew that subscription every 90 days. You need to be selling a considerable volume of units to keep paying the vig.
 

Thread Starter

wongwong

Joined Sep 12, 2021
4
Why do you need to develop it yourself? You already mentioned the need for UL certification. How many have you designed/built already? None from your questions. How long will you take to do this? From experience, if you get there in a year and half a dozen prototypes you'll be doing exceptionally well. Better to buy in a certified supply, or, if you must build it yourself for customisation or embedding reasons, licence in a design from someone like Meanwell and work with them.

Same with motor controller...
I’m currently working as embedded systems engineer.I have experience in doing smps for low power.
I’m going to take on the project for fan control and it’s power supply. But I don’t have much experience for those high power power supply. I found some data sheet of pmic for those smps, just not sure if it would cause issue if I just follow their application circuit.
 

Thread Starter

wongwong

Joined Sep 12, 2021
4
Getting a UL certification is expensive. Maintaining that certification is like buying a subscription to a very expensive magazine that you'll never read, and you need to renew that subscription every 90 days. You need to be selling a considerable volume of units to keep paying the vig.
Yes, it has volume. But I feel worried to use the pmic application circuit for the UL.
I will be in trouble if they tell me I fail at very end stage.
 

MaxHeadRoom

Joined Jul 18, 2013
23,918
I mean I need to develop those power supply myself. I hope receive from you what kind of power supply I should go for?

Thanks all!
As someone who has worked in the motion control industry for some decades, I would never use a SMPS for motor control, and many of the stepper/servo drive manuf. stress the preference of using a linear supply.
If your motor current is not that high, however, you may just get away with it.
 

Papabravo

Joined Feb 24, 2006
17,277
One of the key considerations in using an SMPS for delivering power to a motor is the transient response. The first time we tried it with the spindle motor for a 10 Mb hard drive (ca. 1980) we went to spin up the platter. The startup current was about 5 times the running current. So the +12V motor supply fell to it knees, (Voltage dropped from +12V to about +7V) stayed there for a bit before finally recovering. Needless to say we were a bit underwhelmed with that particular SMPS.
 
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