DRV2603: Can I drive the DRV2603 from the Lipo 3.7V battery, control the vibration intensity via a microcontroller PWM and EN operating at 1.8V and still obtain a strong vibration intensity for driving my LRA motor?

Anmol Saxena2

Part Number: DRV2603
Other Parts Discussed in Thread: DRV2604, DRV2604L

Hello TI Team,

I am using a microcontroller that works at 1.8V.

I have a few questions reg the use of DRV2603 to drive my LRA coin vibration motor.

For my application, I want a strong vibration intensity that can be easily felt on the skin of the user. Also, I want to control the intensity of the vibration (through PWM from a microcontroller). The battery that I am using is a Lipo battery rated at 3.7V and 500 mAH.

My absolutely critical design requirements are: low power, quite strong vibration intensity, vibration intensity should be controllable by microcontroller for providing Low, Moderate and High Vib Intensity levels, smallest possible PCB circuit design for wearable application.

I am exploring some options where I do not have to put additional circuitry for driving the vibration motor, like a Boost converter (5V regulated power supply) or a voltage level shifter to control the DRV2603 through my 1.8V Microcontroller.

Here are my queries:

1. If I drive my DRV2603 circuit by giving 1.8V to the VDD, will the vibration intensity be lesser than if I would drive this IC with a 5V VDD?

2. Supposing if at 5V input power to the DRV2603, the vib motor's vibration intensity is much stronger than the 1.8V input power, then can I give 5V to VDD but still control the ON/ OFF and also vary the vibration intensity through PWM and EN pins that are operating at 1.8V straight from the Microcontroller GPIO (refer to attached picture: Possible Schematic Number 4)? Or would I absolutely have to put a Voltage Logic Shifter between microcontroller and DRV2603 chip and boost the microcontroller GPIO output from 1.8V to 5 V so that the DRV can identify it and allow it to take action (refer to attached picture: Possible Schematic Number 2)?

3. If the answer to my Question 1 is YES, 5V WILL GIVVE STRONGER VIB INTENSITY THAN 1.8V POWER SUPPLY, then If I still want strong vibration intensity while driving the motor at 1.8V, will putting a current amplification buffer circuit at the output terminals of the DRV2603 help?

I have attached a pictorial representation of all my possible schematics herewith. The best possible scenario for me is Schematic No 4 (because I will not have to use a high current buck regulator), if and only if this design can give me very strong vibration intensity.

Request your kind help on the same.

Regards,

Anmol Ajay Saxena

over 4 years ago

0 Anmol Saxena2 over 4 years ago

Prodigy 40 points

Schematic-1.pdf

Schematic 2.pdf

0 Anmol Saxena2 over 4 years ago in reply to Anmol Saxena2

Prodigy 40 points

Schematic 3.pdf Schematic 4.pdf

0 Luis Fernando Rodriguez S. over 4 years ago in reply to Anmol Saxena2

TI__Guru* 84915 points

Hi, Anmol,

Thank you for the information you provided.

Our team will review all the information and provide an answer as soon as possible.

Best regards,
Luis Fernando Rodríguez S.

0 Anmol Saxena2 over 4 years ago in reply to Luis Fernando Rodriguez S.

Prodigy 40 points

Please help me on this. Awaiting your kind response :D

0 Luis Fernando Rodriguez S. over 4 years ago in reply to Anmol Saxena2

TI__Guru* 84915 points

Hi, Anmol,

Thank you for your patience. Our team is still taking a look at your information. You should get an answer today before the end of the day.

Best regards,
Luis Fernando Rodríguez S.

0 Arthur Brown over 4 years ago

TI__Mastermind 20715 points

Hello, Anmol

Thank you kindly for your patience. to answer your query;

1) the DRV2603 output amplitude will be determined by the supply voltage. at 1.8 V the max vibration will certainly be lower

2) from the DRV2603 data sheet a logic high voltage is anything greater than 1.2V therefore at some higher VDD such as 5V, 1.8V logic is OK.

3) certainly if you put some amplification on the outputs you can increase the drive strength to the LRA, however applying amplifiers to the output of the device may very likely make it impossible to use auto resonance with the LRA, without auto resonance the resonance frequency of the LRA wont be tracked and this will likely lead to weaker vibration.

I am also concerned with your desire to drive the device at 1.8 V. the minimum recommended supply voltage from the datasheet is 2.5V. for this reason I cannot recommend you do this, however you can try, and the device might still function.

Since low power consumption is your concern I would like to recommend the low power version of our DRV2604. DRV2604L. which supports VDD of down to 2V, and supports the same PWM functionality. this part is also available in VSSOP package.

In conclusion. I would say that using your schematic 4 with VDD = 3.7 and PWM/EN = 1.8V will function, and likely give satisfactory vibration. Also consider our low power DRV2604L as low power consumption seems to be your concern. For absolute maximum vibration a higher VDD would be needed

May I ask what wearable device you are designing?

Regards,

Arthur Brown

0 Arthur Brown over 4 years ago

TI__Mastermind 20715 points

Hi, Anmol,

Can we provide you any more support?

Regards,

Arthur Brown

0 Arthur Brown over 4 years ago

TI__Mastermind 20715 points

Hi Anmol,

I will be closing the thread.

Regards,

Arthur Brown

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DRV2603: Can I drive the DRV2603 from the Lipo 3.7V battery, control the vibration intensity via a microcontroller PWM and EN operating at 1.8V and still obtain a strong vibration intensity for driving my LRA motor?