Can You Solve This Trouble?

Hello~

Can I ask you some advice about DRV8801 which is full-bridge motor driver.
As the datasheet of DRV8801 shows: it provides a versatile motor driver solution with a variety of capabilities.The device contains a full H-bridge which can be used to drive a brushed DC motor,one winding of a stepper motor,or other devices such as solenoids. A simple PHASE-ENABLE interface allows easy interfacing to controller circuits. The questions I would like to ask that is :
The voltage of electronic machine is about 12.97V when non-loading. This situation is normal. However, the machine cannot operate when loading. The voltage aslo declined to about 6V. After I added a battery--12V, it’s OK to drive loading but the current here is just about 100mA. Why? You can see from the datasheet, its features are : LOW R MOSFETs (0.4ohm Typical0 and 8V--36V operating supply voltage range ?

How to solve this trouble? Please give me some feasible suggestions,thanks again !
Wishes~

What kind of motor do you want to drive with this?
If it's a brushed DC motor, how much Amps will it draw? ( It must be a very tiny motor , 'cause driver current is 2.8A peak )

Hello~o_lampe
It's a brushed DC motor with 2.5A.

Regards

You can start such a 2.5A motor without load only. The current demand at start is much higher than 2.8A. More like 28A
Maybe the driver is in overcurrent protection or the PWM signal from controller is to short to trigger the MOSFets?
Have you considered using motor controller from Radio-Controlled toys instead ? (RC-ESC)
They can be controlled by most 3D printer controller firmware by mimicking a servo.

Anyway thanks for your suggestions !!! o_lampe you are kind !

Best regards~