H bridge driver circuit

[anmolt]

another task at hand....gotta build a driver circuit to drive 4 n-channel MOSFET's.........i built one using an HIP4080AIB FET driver....Vds is being supplied using a car battery(24V) so to use as a switch need to have VGS>24........if anyone can be kind enough to help.......please do.......sux wen im stuck here....cant even ride the bike on sunnier days in akl.....gotta stay put at home....! :no: :no: :no:
im attaching the schematic and the datasheet ....cheers,Anmol.

[dhunt]

Hey if you use that chip it looks like it has boot strapping built in which allows you to have the chip running off 12V and it will ramp up the voltage to an acceptable level to turn the FETs on hard for your 24V.

What are you trying to run? If you don't require change of direction to be supper fast an alternative is using one FET and a relay (DPDT).

[anmolt]

Hey if you use that chip it looks like it has boot strapping built in which allows you to have the chip running off 12V and it will ramp up the voltage to an acceptable level to turn the FETs on hard for your 24V.

What are you trying to run? If you don't require change of direction to be supper fast an alternative is using one FET and a relay (DPDT).

switching needs to be superfast......thats y using this.......not sure how the bootstrapping works...they have given application diagram in the datasheet..will i have to use the amplifier as drawn on page 3(hysterisis mode switching).........cheers........

[dhunt]

switching needs to be superfast......thats y using this.......not sure how the bootstrapping works...they have given application diagram in the datasheet..will i have to use the amplifier as drawn on page 3(hysterisis mode switching).........cheers........
Ok umm what I ment with the relay and FET is the FET is used for PWM so is just as fast as your circuit maybe faster, and the relay is used to change direction (slower, FET off, switch relay, FET on etc)

Boot strapping works by charge a cap up and as the cap charges the voltage is increased and so on to V+diode drop I think if I remember right.

[Dafe]

I agree with DHunt. There should be no problem with the 12VDC source.
The diagram and explanation outline the purpose of your IC's pin10 (AHB).
I would suggest using a standard IN4004 diode for the bootstrap. There is only 30microamps in question, so go smaller if need be.
Due to low current, you'll also get away with a ceramic cap.
I would also have thought FET's to be the fastest method, unless you have some rather large impedences involved.
What are you switching?

[anmolt]

have large current running cuz i gotta get the motor going which is the load for the h-bridge...would i need the amplifier for the sources as shown in the diagram??

[anmolt]

switching direction so that an arm sorta thing attached to the motor can move forwards or backwards.

[Brian d marge]

There are Electrical people on this list ....ahhhhhhhh ...

Sometimes in designing thing I need to use an electrical circuit , ANd while most modern bikes electrics are within my grasp ,,,The stuff below ISNT ..So sometimes I need medication /help ...

Would it be ok, if SOMETIMES ,,,I post an Electrical Question ( read Help needed as I have lost the paddle and am drifting downstream ,,,,)

Kind Regards
Stephen

[dhunt]

have large current running cuz i gotta get the motor going which is the load for the h-bridge...would i need the amplifier for the sources as shown in the diagram??
What amplifier? I don't quite follow.

This is what I would do, see my fine photoshop skills with my fuzzy logic mouse. Much simplier and far as I can understand would probably suit your application ok. Relay switches the direction, FET speed.

[aff-man]

hey anmolt i think you need to explain the situation....

p.s. have you tried the whole changeover to see how it affects the motor in question???

[FlyingDutchMan]

Boot strapping is the way to go, but your 12v power supply looks dodgy. Instead of using a voltage divider network with 10k resistors, put in a voltage regulator with a smoothing cap.

[anmolt]

Boot strapping is the way to go, but your 12v power supply looks dodgy. Instead of using a voltage divider network with 10k resistors, put in a voltage regulator with a smoothing cap.

yup...done that....was a msitake to use the voltage divider..thanks.

[anmolt]

hey anmolt i think you need to explain the situation....

p.s. have you tried the whole changeover to see how it affects the motor in question???

sorry..didnt uunderstand this.........

[aff-man]

sorry..didnt uunderstand this.........

What you are trying to achieve by using the h bridge cause the relays and such are god idea's but you will run into the same problem i told you about with the whole momentum vs magnetic field...

P.s. will text you tomorrow .. might be free sunday arvo

[anmolt]

What you are trying to achieve by using the h bridge cause the relays and such are god idea's but you will run into the same problem i told you about with the whole momentum vs magnetic field...

P.s. will text you tomorrow .. might be free sunday arvo

yup...ur right abt that..another idea i had for preventing the momentum from carrying the arm forward was to have a fishing line or bungee cord(something strong)...that prvents it from going forward....hws that idea????

[dhunt]

yup...ur right abt that..another idea i had for preventing the momentum from carrying the arm forward was to have a fishing line or bungee cord(something strong)...that prvents it from going forward....hws that idea????
To prevent momentum carrying it forward use electric braking. Tie boths sides of the motor to ground when you want it to brake, and it will stop much quicker than just free wheeling.

[anmolt]

To prevent momentum carrying it forward use electric braking. Tie boths sides of the motor to ground when you want it to brake, and it will stop much quicker than just free wheeling.

this wont mess up the motor cuz of such a large retarding force????connect both to ground means ill have to use a switching mechanism here??

[dhunt]

this wont mess up the motor cuz of such a large retarding force????connect both to ground means ill have to use a switching mechanism here??
I'm pretty sure it won't stuff up the motor but .... To ground both ends the easiest way is to use the bottom two FET's in a bridge circuit which means doing something like your orginal circuit but I'm sure you'll manage something.