TPL7407L - Some questions

Hirotaka Matsumoto

Other Parts Discussed in Thread: TPL7407L

Hi all,

Would you mind if we ask TPL7407L?

<Question1>
On the datasheet P11, there is optional diode between VSUP and COM.
How much of rated voltage's diode should we use?

<Question2>
On the datasheet P4 6.3 Recommended Operating Conditions, Recommend confiton of Ids is upto 500mA
Does it mean the total current of CHXX?

Kind regards,

Hirotaka Matsumoto

over 9 years ago

0 Rick Duncan over 9 years ago

TI__Guru** 114905 points

Hi Matsumoto-san,

Our experts have been contacted and should reply soon.

0 Michael J Schultis over 9 years ago in reply to Rick Duncan

TI__Mastermind 24985 points

Hello Matsumoto-san,

1. This diode is used to increase the discharge voltage of the inductor coil. The zener reverse breakdown voltage can be whatever you choose. Around 5V or 12V is appropriate.

2. Yes, 500mA is the recommended maximum current for a given channel. Other limitations to consider are that the device cannot handle >2A at a given point in time.

Additionally, with multiple channels running, depending on the duty cycle there is a recommended maximum current based on thermal limitations of the device. This is described in Thermal Characteristics, section 6.8.

Best,
Michael

0 Hirotaka Matsumoto over 9 years ago in reply to Michael J Schultis

Guru 27585 points

Micheal san

Thank you for your prompt reply!
Our customer uses the zener which reverse breakdown voltage is 20V.
We guess that this is big, right?

Kind regards,

Hirotaka Matsumoto

0 Hirotaka Matsumoto over 9 years ago in reply to Hirotaka Matsumoto

Guru 27585 points

Hi team

Could you give the reply about the zener diode?

Kind regards,

Hirotaka Matsumoto

0 Michael J Schultis over 9 years ago in reply to Hirotaka Matsumoto

TI__Mastermind 24985 points

Hello Matsumoto-san,

20V should be ok as long as the COM pin voltage does not exceed the maximum voltage.
The higher discharge voltage will cause a higher current discharge from the inductor, which should be ok since it will be a short duration, but I have not tried a Zener above 12V.

Are you driving a motor? A Relay?
Are you only using channels 1 through 4, or are you using all 7 channels?

Best,
Michael

0 Hirotaka Matsumoto over 9 years ago in reply to Michael J Schultis

Guru 27585 points

Michael san

Thank you for your reply.

Are you driving a motor? A Relay?
->Our customer are driving unipolar stepper.

Are you only using channels 1 through 4, or are you using all 7 channels?
->Our customer are using all 7 channels.

Kind regards,

Hirotaka Matsumoto

0 Michael J Schultis over 9 years ago in reply to Hirotaka Matsumoto

TI__Mastermind 24985 points

Hello Matsumoto-san,

Please be aware of the note in section 8.2.1 for the device when driving inductive loads (i.e. stepper motor).

This applies when exceed the absolute maximum ratings for negative voltage on the output pins for the device.

Best,
Michael

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TPL7407L - Some questions