12v bridge controller and 24v h-bridge

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1

I made a H-bridge based on the HIP4081A ad the mosfets AUIRFS8409-7P.
The drivers works on 12v and gate to source of the mosfet is 20v max. I use the bridge for controlling a big dc motor.

I want to run the motor with 24v and I have two 12v battery for that so the electronics can be supply 12v and I the motor 24 with the batteries in series.

I just really dont know how to setup everything, I cannot simply supply the h-bridge with 24v and the electronics with 12v directely because the connections between my bridge and driver will burn everythign that work on 12v.

Thanks!
Bernard

2

I just really dont know how to setup everything, I cannot simply supply the h-bridge with 24v and the electronics with 12v directely because the connections between my bridge and driver will burn everythign that work on 12v.

I made a H-bridge based on the HIP4081A ad the mosfets AUIRFS8409-7P.
The drivers works on 12v and gate to source of the mosfet is 20v max. I use the bridge for controlling a big dc motor.

"electronics" (what does that mean ?)

Be specific. "Electronics" ? (means what ?). If you mean "driver chip" then SAY "driver chip."

Clearly there is some language miscommunication here.
Obviously you HAVE NOT made anything, yet...because you are asking us HOW TO wire it.

I believe what you mean to say is:

"My project objective is to build an H-bridge based on the HIP4081A ad the mosfets AUIRFS8409-7P."

"The driver is designed to work on 12V and VGS output= 20V max."

"I want to use the bridge for controlling a big dc motor."

First things first.
Did you read the datasheet for the driver (specifically PAGE 2 BLOCK DIAGRAM)

Did you PAGE 3 ?

Did you UNDERSTAND page 3 ?
(meaning, specifically, can you fill in the blanks ?

1- exactly what device is used for the logic inverter ?
2- exactly what is the device shown at the bottom and what is the function of the circuit it's components comprise ?
3- What would be the most logical assumption as to the specific electrical specifications of the resistors
in the current path of the H-bridge ?
4- What is the MOST IMPORTANT concern (bar none) of a designer when designing a high power H-bridge ? (hint: what ,EXACTLY is he trying to avoid ?)
5- What heatsink(s) would you spec for the mosfets ?
6- What is your expected power dissipation for your load ?
7- You have completely omitted any data or specs for the motor. Do you think that maybe that is something we might have "need to know " ?
8- You posted on the arduino forum, but have yet to mention an arduino in this scenario. Where (or rather "what ") is the arduino ?
9- Have you given any thought to the discrepency between the output voltage of an arduino and the input voltage of the driver ? How do you plan to resolve that ? (part number ?)
10- Why are there two power pins (VCC (pin-15) and VDD (pin-16) on the driver chip ? What voltages should you use on those pins to meet the criteria you specified in your post ?
How would you achieve that ?

Would you care to explain why the DATASHEET for the driver shows the H-BRIDGE powered by 80V (more than triple your 24V) and the "driver chip" powered by 12V ? Would you expect a company with the reputation like Intersil to post a schematic of a circuit that would burn up ? How do you explain that ?

I cannot simply supply the h-bridge with 24v and the electronics with 12v directely because the connections between my bridge and driver will burn everything that work on 12v.

Is this another language miscommunication ?
Can you explain (in electronics terminology ) how you came to this conclusion ?
Can you please state the extent of your "electronics" experience/training/education ?

3

Ok sorry If I wasn't specific enough

Clearly there is some language miscommunication here.
Obviously you HAVE NOT made anything, yet...because you are asking us HOW TO wire it.

No, I've done everything in 12v. The driver is is working properly, motor too, I can drive the speed and direction. What I want is to increase the voltage of the motor (the h-bridge) without increasing the voltage of the driver.

Be specific. "Electronics" ? (means what ?). If you mean "driver chip" then SAY "driver chip."

Yes, I mean the driver and everything around it (caps, resistor, diode,...)

Did you UNDERSTAND page 3 ?
(meaning, specifically, can you fill in the blanks ?

I use 100k resistor for the H/LDEL, some decoupling caps for the driver itself, I didn't put any resistor to the mosfet gate in increase the switching speed and I control both input individually, I don't want an inverting circuit. And arduino is to control the driver. The only thing I don't really know is the "optional current controller"

1- exactly what device is used for the logic inverter ?
2- exactly what is the device shown at the bottom and what is the function of the circuit it's components comprise ?
3- What would be the most logical assumption as to the specific electrical specifications of the resistors
in the current path of the H-bridge ?
4- What is the MOST IMPORTANT concern (bar none) of a designer when designing a high power H-bridge ? (hint: what ,EXACTLY is he trying to avoid ?)
5- What heatsink(s) would you spec for the mosfets ?
6- What is your expected power dissipation for your load ?
7- You have completely omitted any data or specs for the motor. Do you think that maybe that is something we might have "need to know " ?
8- You posted on the arduino forum, but have yet to mention an arduino in this scenario. Where (or rather "what ") is the arduino ?
9- Have you given any thought to the discrepency between the output voltage of an arduino and the input voltage of the driver ? How do you plan to resolve that ? (part number ?)
10- Why are there two power pins (VCC (pin-15) and VDD (pin-16) on the driver chip ? What voltages should you use on those pins to meet the criteria you specified in your post ?
How would you achieve that ?

1- None (arduino)
2- A current controller? I don't what that (i think)
3- Control the current? In case of shorts?
4- shoot-through (shorts)
5- None, for now my motor don't have load and the mosfets don't get warmer than room temp, I will add some heatsink when I will need it.
6- I dont know yet
7- The motor are Bosch EV Warrior
8- Arduino is controlling the driver
9- I haven't really think about that. I plug directly the arduino to the driver (BLI/ALI) with a pull down resistor. It's working well.
10- To power the driver (and gate of the mosfet), 12v

Would you care to explain why the DATASHEET for the driver shows the H-BRIDGE powered by 80V (more than triple your 24V) and the "driver chip" powered by 12V ? Would you expect a company with the reputation like Intersil to post a schematic of a circuit that would burn up ? How do you explain that ?

I don't know but it's looking somehow at what I want but 24v and not 80v (I guess the 80v is a max)

I cannot simply supply the h-bridge with 24v and the electronics with 12v directely because the connections between my bridge and driver will burn everything that work on 12v.

Can you explain (in electronics terminology ) how you came to this conclusion ?

I burned down my HIP4081A and two mosfet.

And I'm french, I'm trying my best to be as understandable as possible.

If you ahve any question or solution for what I want to do, please yourself.

4

I burned down my HIP4081A and two mosfet.

How do you know that it wasn't due to shoot-through because you are breaking the most important rule of using an h-bridge ? You are relying on software to ensure that BLI is the inverse of ALI. I would never do that. I would spend a $1 on a CD4069 CMOS Inverter chip and run all six gates in parallel and use the entire chip as the single logic inverter you see that inverts ALI . If you were using the proper current monitoring methods you would have detected a problem and shutdown the system before anything could burn up. As you can see from the data sheet, as long as you do not exceed the driver Vcc max rating of 16V on Vcc or Vdd, you should be fine.

There is absolutely no data to support your conclusion that you cannot run the driver on 12V and the motor on 24V (or even 80V). The most logical conclusion is that your decision to use software to prevent the low side devices turning on while the high side devices are still resulted in both high and low side devices turning on , causing the dreaded "shoot-through". Get a CD4049 or CD4069 parallel
all six inverters and use that to invert ALI. If you can present some data supporting your conclusion, I am willing to look at it but as it stands, it looks like the problem that caused your parts to burn up was "operator error".

The current controller can be replaced by an op amp differential amplifier. I would use and LT1215 OP AMP differential amplifier Send the output of that circuit to an analog input and monitor the voltage drop across your 100A current shunt . You can also use the Hall effect RC version. You're ignoring the obvious. The datasheet says there is no problem doing what you blame for burning up your parts. Who do you think is right ? (you or Intersil ?) You should not be omitting that logic inverter. It is there for a reason. And you SHOULD be monitoring the current so you can implement current control. Get it right before using it. The current protection is critical for high power applications. Don't cut corners by ignoring it.

5

The HIP4081 has built in shoot-through prevention, no need for external logic for that at all -
if you read the datasheet you'll see both inputs high deliberately to make PWM driving easy.

These MOSFET driver chips impose only a maximum motor voltage condition - the driver runs
from a clean 12V supply, the bridge itself can be any voltage from 0V to 80V (and as dirty as
you want subject to no spikes over 80V) - in fact you can perfectly safely power down the bridge
or the driver independently with no risk - bootstrapped gate supply to the high-side drivers takes
care of that.

Completely agree with current monitoring - only you need damn fast current monitoring for
handling short circuits - the current sensing circuit straight into a comparator driving the DIS
input. Most MOSFETs are rated for a few microseconds only of short-circuit load, far beyond
what software protection can give. The easy way to current protection is to use a power supply that
cannot generate too much current for the devices in the first place.

6

Page 3 of the datasheet shows "Typical Application" schematic with logic inverter inverting ALI . Output of that gate goes to BLI input. Definition of "shoot-through" is ALI and BLI both on at same time. If you are correct that inverter should be internal.

I did see this:

The HIP4081A can drive every
possible switch combination except those which would
cause a shoot-through condition.

FYI Application Note for HIP4081 is AN9405.5
There is one thing that confuses me about the "typical application" schematic"
See attached schematic for comparison
When you look at that schematic, it is obvious that the direction of a dc motor is controlled by PWM INPUT A and it's compliment (inverse) on PWM INPUT B. For simplicity, if you simply turn on the motor without pwm, a HIGH on input A turns on Q2 and it's compliment (a LOW) on input B , turns on Q3 (because the high side devices are P-channel).

Thus Input A=L, B= H turns on Q1 & Q4
Input A=H, B= L turns on Q2 & Q3

Note: The TC4427 has a similar feature that ignores any input combination other than the ones just listed, but lacks the sophisticated timing you see in the HIP4081A Functional Block Diagram on page 2 of the datasheet. In that block diagram you can see the internal logic inverter from the ALI input feeding the AND gate that goes to the "Turn On delay , the output of which goes to the "Level Shift & Latch". There are two things that should be noted when comparing the attached schematic and the HIP4081A. First,
the attached schematic has an inherent "shoot-through" protection in that it utilizes N-channel mosfets for LOW-side devices and P-channel for HIGH-side devices and ties the respective gates together on the left and the right. The result is that there is no way to energize a lowside device and a high side device on the same side. The TC4427 then adds the further protection of ignoring any combination of inputs other than the two combinations listed above.
The other thing to note is that the HIP4081A schematic uses ONLY N-channel devices.

However, if you look at the HIP4081A functional block diagram you can see there is a very sophisticated combination of circuitry specifically aimed at preventing shoot-through. While it is simple to see how the attached schematic changes motor direction (simply inverting logic of complimentary inputs), it is not so easy to see how you would change motor direction with the HIP4081A. If you can figure that out I would be curious to know. I see only one input for the "Typical Application" schematic.

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7

These MOSFET driver chips impose only a maximum motor voltage condition - the driver runs
from a clean 12V supply, the bridge itself can be any voltage from 0V to 80V (and as dirty as
you want subject to no spikes over 80V) - in fact you can perfectly safely power down the bridge
or the driver independently with no risk - bootstrapped gate supply to the high-side drivers takes
care of that.

Thanks for your answer, but the first time I tried I burned up a side of mosfet (finally the driver seems fine) and I'm kinda scared to try again the same thing. What do you think is the most probable source of problem. What I remember when this happened is that I connected the second battery and than about a sec later, sparks start going up on the battery connector ( the mosfets were shorted) but it didn't sparked immediately when I touch the connector of the battery), and the driver was hot as hell.

The pins A/BHS on the driver are connected to the higher side, so they will bring 24v to the driver. Is this supposed to be this way?

Ok I will look into a fast current monitoring circuit, but I don't think it will do the trick, if the mosfet or the driver or anything burned out, the disable pin is useless, something that can cut the current from the batteries would be better.

8

Ok I will look into a fast current monitoring circuit, but I don't think it will o the trick, if the mosfet or the driver or anything burned out, the disable pin is useless, something that can cut the current from the batteries would be better.

I'm more in favor of old school h/w interlocks where the circuitry handles the shutdown automatically without any s/w intervention. The current monitoring circuit would have a logic output that controls the DIS input. The uC would not be in that loop, though it could monitor the current monitoring circuit and read the analog output of that circuit but would not be involved in the circuitry that performs the shutdown. By adding voltage comparator to the current monitoring circuit , it could be made to trigger the DIS input when the current exceeded the specified limit. As far as "Failure Analysis" of your first attempt, I would wonder what exactly you mean by "connecting the second battery". The whole system should have had two switches :
LOGIC POWER (+12v)
MOTOR POWER (+24v)

BOTH of which should have been OFF when connecting the batteries, preventing ANY current flow to the motor Vdd terminal at the top of the h-bridge. The logic power should alway be energized FIRST and then the motor power second. In most industrial applications , the uC handles EVERYTHING. You turn on the uC system power and then you press a button (labeled Motor Pwr ON) on a panel which , when read by the uC, energize a large contactor and apply power to the mosfet Vdd.

I still believe it was "operator error" that caused the melt down. Don't take this the wrong way but I think the simple explanation is "system failure due to poor design".
In a professional (industrial ) environment, there would have been numerous initial tests with no motor connected. It would have been replaced with a large power resistor dummy load that would prevent excessive current during testing of the logic systems.
Since you are not a professional there is no way you could know this but that doesn't mean you couldn't have first posted here at the beginning with the question:
"I am not a Power Electronics Technician or Engineer , but I want to build a high current DIY H-BRIDGE motor driver using these components. How can I test the system without risking catastrophic failure and damage ?
This
would make a good sensor. You would need to add the rest of the circuitry and then test the system with dummy loads to calibrate it. You would need an op amp voltage COMPARATOR and a CMOS chip (CD4049 or CD4050 ) to convert the output of the schmitt trigger to a 12V logic signal for the DIS input.

Measures Bi-directional DC and uni-directional AC currents
Low noise, Low loss Monolithic Hall IC
Fast and accurate analog output
High isolation from measured circuit
May be used as High-side or Low-Side sensing
3V to 5V single supply operation
Measured circuit up to 300V AC/DC
High capacity stitched copper pads
Analog output proportional to measured current
Flexible connection and mounting options
Easy to deploy with most uController systems

9

Here my schematic.

I will look into this 100amp current sensor, it can be useful.
For sure, I'm not a professionnal, I don'nt even own a bench power supply, oscilloscope or amp meter. It's quite surprising that I was able to set up an HIP4081A.

As dummy load, I used some LED with resistor so the current was something like 20mA. After I used a motor of about 1 amp, and than the big one.

However, if you look at the HIP4081A functional block diagram you can see there is a very sophisticated combination of circuitry specifically aimed at preventing shoot-through. While it is simple to see how the attached schematic changes motor direction (simply inverting logic of complimentary inputs), it is not so easy to see how you would change motor direction with the HIP4081A. If you can figure that out I would be curious to know. I see only one input for the "Typical Application" schematic.

To control the direction, there is two ways ( I think). 1st: You set up an inverting circuit on one off the input of the driver. Than with pwm, when you are at 50% , the motor don't move because it will go forward 50% of the time and backward 50% of the time. To go forward or backward, you increase or reduce the duty cycle. So 100% would be max speed forward and 0% is max speed backward.

2nd: You control each input individually. When connected to ground,the high side is ON, when you apply pwm on one side, it will start moving forward (or backward) and to inverse the direction, you stop the pwm on the side that was controlled and start on the other side.

I'm maybe no the best to describe how it is working, I'm still very new to the subject

10

raschemmel:
While it is simple to see how the attached schematic changes motor direction (simply inverting logic of complimentary inputs), it is not so easy to see how you would change motor direction with the HIP4081A. If you can figure that out I would be curious to know.

Direction and speed are controlled via the control lines: AHI, ALI, BHI, BLI.
With AHI set high, ALI is PWM'd to vary speed in that direction (BHI and BLI must be Low).
With BHI set high, BLI is PWM'd to vary speed in that (the other) direction (AHI and ALI must be Low).
The device datasheet defines all that on its "Page 6".
I would not tie DIS low.

see Reply #12

11

Truth Table , bottom of page 5

12

Just to confirm, with regard to the bare bones h-bridge with no driver chips, if you want to use PWM , all you have to do is turn on one side of the h-bridge (either the lo or the hi side, and then PWM the opposite complimentary side of the bridge, right ? (ie; turn on L lowside and PWM R highside , or vice versa, meaning you never pwm both L & R side . (because there's point in that)
which explains why you pull BLI & BHI LOW , Enable AHI with a HIGH and PWM ALI , or the opposite: Pull ALI & AHI LOW , Enable BHI with a HIGH and PWM BLI.

13

You got me. [Previous post edited.]
Turn on the A or B side's "HI" and PWM its complementary "LO"
AHI = 1, BLI is PWM'd for speed. [BHI = 0, ALI = 0]
BHI = 1, ALI is PWM'd for speed. [AHI = 0, BLI = 0]

AHI goes with BLO.
BHI goes with ALO.
AHO on with BLO on; BHO on with ALO on. [There, got it. Can't help but laugh.]
Anticipating A HI and LO going together and B HI and LO going together... I can see stuff going poof !. BUT the "truth table" tells us that cannot happen. I would write my sketch as though it could.

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14

That sounds consistent with my last post.

That sounds like a "YES".

15

raschemmel:
That sounds consistent with my last post.

That sounds like a "YES".

I "+1" that.

16

Thanks for the confirmation.

17

FYI, I'm not sure what you mean by this :

AHI goes with BLO.
BHI goes with ALO.

BLO is the label given for B lowside Output
The complimentary PWM input for AHI is BLI (B Lowside Input)

likewise
ALO is the label given for A lowside Output

The complimentary PWM input for BHI is ALI (A Lowside Input)

As you stated here:

Turn on the A or B side's "HI" and PWM its complementary "LO"
AHI = 1, BLI is PWM'd for speed. [BHI = 0, ALI = 0]
BHI = 1, ALI is PWM'd for speed. [AHI = 0, BLI = 0]

So , what do you mean by this ?

AHI goes with BLO. (do you mean B lowside Output or B Lowside Input ?)
BHI goes with ALO. (do you mean A lowside Output or A Lowside Input ?)

On a different subject:
@OP,
Is your setup designed for one direction only ? If so , isn't an H-bridge overkill ?

18

raschemmel:
So , what do you mean by this ?

AHO goes with BLO
(laughling quietly to myself)
and
BHO goes with ALO.
Those abbreviations cum mnemonics... are horrible (AHO, really.)

19

AHI goes with BLO.
BHI goes with ALO.

AHO on with BLO on;
ALO on with BHO on

. [There, got it. Can't help but laugh.]
(there was a misunderstanding on my part . I thought you were talking about inputs but you were talking about outputs so forget my question. We weren't even on the same page, my fault)

But now that I know what you were saying,
Is there any surprise there ? Of course your correct. it is, after all , an h-bridge so there's only two polarities possible for the motor.

I think what confused me was I wasn't expecting you to state something so obvious so I thought you must be trying to say something else and the mixup with the abreviations threw me off.
No problem.

20

I don't want to interrupt your little discussion, but for the bootstrap diode, should I use some MUR220G or MUR115G instead of my 1N4002?