h bridge not working

mosh poll

Prodigy 70 points

Other Parts Discussed in Thread: SN754410

I tried 4 new sn754410 non of them worked. the motor sits still.

its for a dc motor

pin 1,2,7,16 was connected to plc that has 5 volt outputs (2 and 7 one at a time)

pin 8 to positive side of 12 volt 1 amp power supply

pin 4,5 to negative

pin 3,6, to motor

I checked with voltmeter on pins 1,2,7,16, the actual voltage was 4.83 volts

I checked pin 8 and it was 12 volt

I never used this ic before

I don't see why it shouldn't work. I guess I miss something

over 10 years ago

0 Rick Duncan over 10 years ago

TI__Guru** 114905 points

Hi Mosh,

Our expert has been contacted and should reply soon. While waiting, can you provide your motor specifications?

0 mosh poll over 10 years ago in reply to Rick Duncan

Prodigy 70 points

12v 155ma

0 Rick Duncan over 10 years ago in reply to mosh poll

TI__Guru** 114905 points

Hi Mosh,

Please report the voltage on pins 3 and 6? From your description, both should be approximately 10V. If both are 10V, please set either pin 2 or 7 to ground. This will create a voltage differential across the motor.

Also, please connect pins 12 and 13 to negative also.

0 mosh poll over 10 years ago in reply to Rick Duncan

Prodigy 70 points

pin 3,6, are 0 volt

connected pin 2, to 5 volt and pin 7, to negative

also pin 12, and 13 to negative

not working

0 Rick Duncan over 10 years ago in reply to mosh poll

TI__Guru** 114905 points

Hi Mosh,

If you have not done so, please remove the motor and debug using the table 1. If the outputs do not follow the function table, there may be something wrong with the device. If the outputs do follow the function table, does VCC2 have enough current capability to drive the motor from startup?

0 mosh poll over 10 years ago in reply to Rick Duncan

Prodigy 70 points

I put a much smaller motor and is working.

however when I want to control the same motor with the other side of the ic it turns only when pin15, is positive and pin 10, is negative

but when I want to reverse direction it does not work I olso measured the voltage on pin 14, and 11, and no volt

0 Michael J Schultis over 10 years ago in reply to mosh poll

TI__Mastermind 25235 points

Mosh,

So the smaller motor works on one side of the IC (output pins 3 and 6) in both directions?
But the other side of the IC (output pins 14 and 11) only allows you to rotate the motor in a single direction?
If pin 9 and pin 10 are 5V and pin 15 is grounded, pin 11 should be 12V and pin 14 should be 0V. Is this not the case?

Best,
Michael

Motor drivers

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h bridge not working