Author Topic: 1.8V H-Bridge  (Read 947 times)

0 Members and 1 Guest are viewing this topic.

Offline mrburnzieTopic starter

  • Regular Contributor
  • *
  • Posts: 139
  • Country: cs
1.8V H-Bridge
« on: January 05, 2020, 09:21:17 pm »
Hi,

I'm designing a simple h-bridge with a couple of mosfets, and my question is can I use 1.8V gate signals?
What should I exactly look in the datasheet to confirm this? (I have been looking at Vgs and the values are 1V and -1.2V)

The mosfets are DMN2230U (https://www.diodes.com/assets/Datasheets/ds31180.pdf) and DMG2301L (https://www.diodes.com/assets/Datasheets/DMG2301L.pdf)

I'm just looking for a cheap h-bridge solution to use at 1.8V.

Thanks!
"Talk is cheap, show me the code"

Anyone need of freelance software/hardware developer, hit me up!
 

Offline mrburnzieTopic starter

  • Regular Contributor
  • *
  • Posts: 139
  • Country: cs
Re: 1.8V H-Bridge
« Reply #1 on: January 05, 2020, 09:21:51 pm »
Just realized that I have put both sides to be channel A  |O
"Talk is cheap, show me the code"

Anyone need of freelance software/hardware developer, hit me up!
 

Offline magic

  • Super Contributor
  • ***
  • Posts: 7453
  • Country: pl
Re: 1.8V H-Bridge
« Reply #2 on: January 05, 2020, 09:42:47 pm »
Look what's the guaranteed RDS(on) at Vgs=1.8V and whether it's good enough for you.

Your first link says 230mV at 1.8V right at the top of the first page. In the detailed specification it further states that this is guaranteed for currents up to 1A and that the typical value should be slightly less.
 

Offline RoGeorge

  • Super Contributor
  • ***
  • Posts: 7012
  • Country: ro
Re: 1.8V H-Bridge
« Reply #3 on: January 05, 2020, 10:28:17 pm »
Just realized that I have put both sides to be channel A  |O

Also the transistors in the upper side of the bridge should switch their place with the ones from the lower side, and the Drain and Source terminals in the upper side must be switched between them, and some other details that won't make sense to discuss before fixing the schematic.

My advice is to search for a schematic of a "H bridge with complementary MOSFET" if that's what you want to use (search for images) and start from there.

About the question if an 1.8V I/O can control those MOSFET, no, it won't work, even after correcting the posted schematic.  VGS must be 1.8V or lower in order for a MOSFET to be controlled by an 1.8V signal.  MOSFET transistors with low VGS are sometimes called "Digital MOSFET" or so, so that would be a good term to search for, then look in the datasheets and pick some MOSFETs with VGS 1.8V or lower.



Be careful with batteries and H bridges.  Even when the design is OK they can still catch fire or explode, not kidding.

Always put a fuse in series with the battery, NEVER skip the fuse.

Offline Yansi

  • Super Contributor
  • ***
  • Posts: 3930
  • Country: 00
  • STM32, STM8, AVR, 8051
Re: 1.8V H-Bridge
« Reply #4 on: January 06, 2020, 12:03:39 am »
Not to mention the nasty cross-conduction current and that it won't work with higher than 1.8V battery voltage.

 
The following users thanked this post: thm_w

Online langwadt

  • Super Contributor
  • ***
  • Posts: 4857
  • Country: dk
Re: 1.8V H-Bridge
« Reply #5 on: January 06, 2020, 12:33:38 am »
 
The following users thanked this post: thm_w

Online mikerj

  • Super Contributor
  • ***
  • Posts: 3382
  • Country: gb
Re: 1.8V H-Bridge
« Reply #6 on: January 06, 2020, 11:24:01 am »
What is the battery voltage range?  A couple of extra transistors (could be bipolar) would allow the gates to be driven from the battery voltage which may ease the Vgs concerns.  Is this for low speed on/off operation or are you wanting higher frequency PWM control?  Obviously fix the transistor positions first!
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf