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Offline Warhawk87Topic starter

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Re: Motor Controller
« Reply #30 on: July 29, 2010, 04:19:04 PM »
The UCC27424P is only rated for 4 amps... Does that mean if my motor stalls the circuit goes poof?

Offline waltr

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Re: Motor Controller
« Reply #31 on: July 29, 2010, 07:00:57 PM »
Check the data sheet. Many of the H-bridge driver/controller chip have either built-in over current protection or a external current sense resistors that will shut-down the output drivers.

Offline Warhawk87Topic starter

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Re: Motor Controller
« Reply #32 on: July 29, 2010, 07:45:16 PM »
http://octopart.com/ucc27424p-texas+instruments-455107

I dont see anything about a current protection device and I just had a thought, can I run two motors in both directions with only 1 of these?  And I dont have a single idea how to work one of these 0.o

Offline Warhawk87Topic starter

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Re: Motor Controller
« Reply #33 on: July 29, 2010, 08:03:25 PM »
I was just looking at the diagrams for the TLE 5206-2G and I wanted to know if i had this straight....

The motor is connected from the bridge at OUT1 and OUT2 and you have two logic voltages going into IN1 and IN2.... Activating one of the INs causes the motor to go one way, activating the other makes it reverse, and activating both makes it brake?  And if thats right then I can only control one motor with this correct?

I'm going to take a look at the other now and see what I can find out...

Offline futmacl

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Re: Motor Controller
« Reply #34 on: July 29, 2010, 08:26:45 PM »
I was just looking at the diagrams for the TLE 5206-2G and I wanted to know if i had this straight....

The motor is connected from the bridge at OUT1 and OUT2 and you have two logic voltages going into IN1 and IN2.... Activating one of the INs causes the motor to go one way, activating the other makes it reverse, and activating both makes it brake?  And if thats right then I can only control one motor with this correct?

I'm going to take a look at the other now and see what I can find out...

You can drive more than one motor if the total current needed stays within the limits for that IC - but you can't drive them independently. There are some dual motor drivers, but they are usually pretty expensive, it's often cheaper to just go with two separate ICs.

As for ratings - yeah, UCC27424P has an absolute maximum rating of 4.5A. TLE52052 does 6A and is in stock, though.

Offline Warhawk87Topic starter

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Re: Motor Controller
« Reply #35 on: July 29, 2010, 08:52:11 PM »
So two TLE52052 to control two DC motors?  Sounds good!  And i assume what i said about how they work is correct?

Offline futmacl

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Re: Motor Controller
« Reply #36 on: July 29, 2010, 09:26:51 PM »
So two TLE52052 to control two DC motors?  Sounds good!  And i assume what i said about how they work is correct?

Yes, except I think they're high impedance when both inputs are high, and braking when both are low. But should be easy.

Offline Warhawk87Topic starter

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Re: Motor Controller
« Reply #37 on: July 30, 2010, 12:31:42 PM »
What do you mean by high impedance? I dont know what that means  :-\

Offline futmacl

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Re: Motor Controller
« Reply #38 on: July 30, 2010, 01:24:11 PM »
What do you mean by high impedance? I dont know what that means  :-\

You can just consider this an equivalent of disconnecting motor leads.

In the "brake mode", both leads are shorted (by being simultaneously connected to Vcc or GND), which causes the motor to slow down more rapidly and requires more torque to be moved once stopped - it operates exactly the same to a dynamo with an infinite load. In "freewheeling" high-impedance mode, leads are floating, and therefore, the load is removed - and the motor slow downs more gradually and is easier to operate.

[ Note that neither of these modes is really suitable for stopping the motor in place - to do this, you need to first enter brake mode for a very short time, and then reverse direction briefly. ]

All full H-bridge motor drivers support braking, but not all support freewheeling. This one does, which is nice (it potentially allows for more efficient PWM, for example).

Offline Soeren

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Re: Motor Controller
« Reply #39 on: July 30, 2010, 06:36:12 PM »
Hi,

[...] if you are happy with 4A, UCC27424P is a single chip that goes for under $3.
UCC27424P is a MOSFET driver (i.e. not a motor controller!) and won't sustain anything like 4A, which is just the peak pulse rating that it will deliver driving a MOSFET past the Miller plateau.
The sustained current is less than 300 mA.
Regards,
Søren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?
Please remember...
Engineering is based on numbers - not adjectives

Offline Soeren

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Re: Motor Controller
« Reply #40 on: July 30, 2010, 06:51:57 PM »
So two TLE52052 to control two DC motors?  Sounds good!  And i assume what i said about how they work is correct?


Yes, except I think they're high impedance when both inputs are high, and braking when both are low. But should be easy.

Not quite:

Better resolution

Edit: And the continuous current is 5A, not 6A.
« Last Edit: July 30, 2010, 07:05:41 PM by Soeren »
Regards,
Søren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?
Please remember...
Engineering is based on numbers - not adjectives

Offline Warhawk87Topic starter

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Re: Motor Controller
« Reply #41 on: July 30, 2010, 07:03:20 PM »
Just for clarification, High means your applying power and low means your not?  Because if they're both low i would like my motors not to move, but both low makes the motor turn clockwise in your table

Offline Warhawk87Topic starter

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Re: Motor Controller
« Reply #42 on: July 30, 2010, 07:36:02 PM »
Also I'm having trouble finding a place that sells the TLE52052 individually.... Most of them are "minimum of 100" or out of stock

Offline Webbot

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Re: Motor Controller
« Reply #43 on: July 30, 2010, 08:30:30 PM »
Also I'm having trouble finding a place that sells the TLE52052 individually.... Most of them are "minimum of 100" or out of stock

Digikey seems to have them as individual parts either as SMD or Through hole
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Offline Webbot

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Re: Motor Controller
« Reply #44 on: July 30, 2010, 08:42:26 PM »
The truth table for this device (lifted by Soeren from the datasheet in previous reply) shows that it will be difficult to use with PWM without additional circuitry.

ie for clockwise you will need to flick the 2 pins between Low/Low and High/High
and for anticlockwise between Low/High and High/High

But if you aren't interested in speed control - ie you just want full speed fwd, full speed reverse, brake and coast then you are ok.
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Offline Warhawk87Topic starter

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Re: Motor Controller
« Reply #45 on: July 31, 2010, 12:13:13 AM »
Well you cant expect too much from a cheap component right?  And digikey says something "timed out" and no its not my account

 


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