DRV110: PIN OSC

Cedrick

Part Number: DRV110

Hi,

Greetings.

Our customer was designing a circuit around the DRV110. They also have DRV110EVM at hand.

They noticed that the internal oscillator is not running on their prototypes. On the working T.I. Evaluation module, pin 5 (oscillator), the oscillator is running and a small signal waveform can be seen on the oscilloscope in the range of 50mv to 100mv peak. On each of their prototype modules, the oscillator pin has a 1-volt level with no signal and it appears that the internal oscillator is inoperative. They have not seen anything that would shut down this free-running oscillator. Referring to the input supply, we have a regulated 12-volt source feeding the DRV110 through a single 500 Ohm series resistor. This should be adequately below the internal Zener value.

Can you please help us on this matter? I would appreciate if you could tell us the possible reasons that might cause this issue.

Thanks.

Regards,

Cedrick

over 4 years ago

0 Grant Falkenburg over 4 years ago

TI__Intellectual 1965 points

Hi Cedrick,

Thanks for your question. Let me contact the expert for this part. You can expect a response by 11/15/19.

Best,

Grant

0 Cedrick over 4 years ago in reply to Grant Falkenburg

TI__Expert 8270 points

Hi Grant,

Thank you. I will be waiting for it.

-Cedrick

0 Costin Cazana over 4 years ago in reply to Cedrick

TI__Expert 4940 points

Hi Cedrick,

Osc pin sets the current for the internal PWM oscillator, the PWM frequency can not be monitor externally.

The only place to monitor is Output- the FET gate driver. This can be done only in a close loop with all the external components: FET, sense resistor and solenoid. Depending on the solenoid slew rate current the duty cycle may go >100%, the PWM freq at OUT pin will be lower than the internal PWM frequency.

Regards,

Costin

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DRV110: PIN OSC