PWM Signals output

Richard Dualmann

Other Parts Discussed in Thread: DRV8301, DRV8312

Hi,

I have a DRV8301-RM46-KIT board as the http://www.ti.com/tool/drv8301-rm46-kit.

As removing the wires from this control board, the DRV8301 output gate signals will be disable one of three (ABC) channels.

To make sure that the at least ABC three PWM channels signals via DRV8301 are good but unmounted a BLDC motor.

What is the problem?

Where has this setting?

Thanks.

over 13 years ago

0 Haixiao Weng over 13 years ago

TI__Genius 13810 points

I don't quite understand your question. Which wire did you remove? Three things need to be checked if you can not find the expected PWM:

1) Does the RM46 generate the PWM correctly? please check J5 on the DRV8301 board.

2) Was the DRV8301 enabled? Pin 6 on J5 of the DRV8301 board, or look at the control card LED, the EN_DRV LED. The LED is controlled by the MCU+ the TPS65381 device.

3) Was any flag (like short, over temp) set on DRV8301? Look at the DRV8301 board to see if any red LED turned on. Any you can read the DRV8301 status though SPI.

Regards,

Haixiao

0 Richard Dualmann over 13 years ago in reply to Haixiao Weng

Intellectual 560 points

I have removed the motor 4-wire from four power terminals,

then the PWM signals appear miss-fire problem in some channels (1, 2, or 3) measured in the scope.

0 Haixiao Weng over 13 years ago in reply to Richard Dualmann

TI__Genius 13810 points

You are running the orignal firmware or you built some firmware yourself?

Sounds to me either the DRV8301 sensed a over current or the the DRV8301 is not enabled.

Regards,

Haixiao

0 Richard Dualmann over 13 years ago in reply to Haixiao Weng

Intellectual 560 points

The original firmware.

I have no any further programming to do.

In C2000 (F28035) with DRV8312 board, the same problem exists still.

0 Richard Dualmann over 13 years ago in reply to Haixiao Weng

Intellectual 560 points

No, the motor is disconnected.

There is no any chance to be an over current.

Another two channels are worked well, that is, the gate has been enabled.

There is one channel no signal out only.

It seems to the DRV 8312 or 8301 has some kinds of protection onchip, maybe not a software controlled.

0 Haixiao Weng over 13 years ago in reply to Richard Dualmann

TI__Genius 13810 points

Assume no motor wires are connected, connect the USB to PC, open the USB -UART hyperterminal, 19200 baud rate, no parity, 8data bits, 2 stop bits, re-boot the system.

Now you should be able to see some outputs on the hyperteminal.

Type '1' in the hypertermal to enable the TPS power suppy devices.

Then the hypertermal should tell you ' motor enabled'.

At this point, you should find 50% duty cycle in the U, V, W connections. (where is connected to the motor)

0 Richard Dualmann over 13 years ago in reply to Haixiao Weng

Intellectual 560 points

No, as your mentioned above,

The observed PWM singals are just generated by MCU, not DRV8301 output signals.

In fact, my problem is the DRV8301 miss-fire if no motor mounted, i.e., no output signals appear in some channel 1 or 2 or 3.

0 Haixiao Weng over 13 years ago in reply to Richard Dualmann

TI__Genius 13810 points

Sounds like it is a question to the motor pre-drive. You can post the question to http://e2e.ti.com/support/applications/motor_drivers/f/38.aspx

Regards,

Haixiao

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PWM Signals output