# IR2110 - Half bridge waveform

Thread Starter

#### Coucou80

Joined Apr 7, 2018
78
I designed a circuit to power a little dc motor through the use of Half-bridge powered by a ir2110 ic.
The good news is on the scope I see the MOSFET gates opening at opposite timing (DC - from ~0 to 12 volt for LO and DC - from ~ 0 to + Vs + 12 Volts for HO).
So here is my question. At load location what should the waveform look like? AC or Pulse DC ?

#### dcbingaman

Joined Jun 30, 2021
1,065
Pulsed DC from what I can make out looking at the datasheet.

#### LowQCab

Joined Nov 6, 2012
4,289
You need to supply a Schematic so that we can see what You are attempting to do.
You also need to explain the purpose of your Circuit.
.
.
.

#### MrSalts

Joined Apr 2, 2020
2,767
You need to supply a Schematic so that we can see what You are attempting to do.
You also need to explain the purpose of your Circuit.
.
What's not clear?
I designed a circuit to power a little dc motor through the use of Half-bridge

#### MrSalts

Joined Apr 2, 2020
2,767
I designed a circuit to power a little dc motor through the use of Half-bridge powered by a ir2110 ic.
The good news is on the scope I see the MOSFET gatea opening at opposite timing (DC - from ~0 to 12 volt for LO and DC - from ~ 0 to + Vs + 12 Volts for HO).
So here is my question. At load location what should the waveform look like? AC or Pulse DC ?
Assuming your switching speed (changing directions) is much slower than the start-up time of the motor, you'll see essentially a square wave. There will be some rounding of the leading edge of the wave as the motor changes direction.

If you change direction so quickly that the motor is not up to speed before switching direction, you will see some type of triangle wave. The faster you switch, the lower the peak-to-peak voltage you will see on your scope (assuming to "switching" means your input swings enough to turn off the N-channel and turns on the P-channel in one flip). If a switching event can stop at zero-volts and leave both N and P channels off, then your waveform will look more ie a sawtooth at high switching speeds.

Thread Starter

#### Coucou80

Joined Apr 7, 2018
78
Thank you all for the interest in my post. I'm impressed with the numerous responses I got and the quality of the observation received in such a quick time
To get back to topic, if we look at this video (which has nothing to do with my particular project) : Ultrasonic Mist Maker || DIY or Buy - YouTube from 5:10 to 5:18 the author mentions that Half-Bridges produces an AC signal and this is what is confusing me .... I dont see how a Half-Bridge can produce an AC signal unless "maybe" if coupled with a transformer. H-Bridge would ba a totaly different beast though and it is not what I'm attempting to construct.

In my mind a square wave is AC signal as it alternates from positive to negative in a "square wave maner". While pulse DC signal is not crossing the 0volt line. Author seems to explain that the signal crosses the 0 line with the use of a half-bridge.

Last edited:
Thread Starter

#### Coucou80

Joined Apr 7, 2018
78
I just solved it… I had a mistake in my connection.
Waveform output at motor is ac square wave

Similar threads