13

DRV8835

www.ti.com

SLVSB18H – MARCH 2012 – REVISED AUGUST 2016

Product Folder Links: DRV8835

Submit Documentation Feedback

Copyright © 2012–2016, Texas Instruments Incorporated

8.2.2 Detailed Design Procedure

8.2.2.1 Motor Voltage

The appropriate motor voltage depends on the ratings of the motor selected and the desired RPM. A higher

voltage spins a brushed DC motor faster with the same PWM duty cycle applied to the power FETs. A higher

voltage also increases the rate of current change through the inductive motor windings.

8.2.2.2 Lower-Power Operation

When entering sleep mode, TI recommends setting all inputs as a logic low to minimize system power.

8.2.3 Application Curve

The following scope captures motor startup as VCC ramps from 0 V to 6 V. Channel 1 is VCC, Channel 2 is VM,

and Channel 4 is the motor current of an unloaded motor during startup. The motor used is a NMB Technologies

Corporation, PPN7PA12C1. As VCC and VM ramp, the current in the motor increases until the motor speed

builds up. The motor current then reduces for normal operation.

Inputs are set as follows:

•

Mode: IN/IN

•

AIN1: High

•

AIN2: Low

Channel 1: VM

IN1 = Logic High

Channel 2: VCC

IN2 = Logic Low

Motor used: NMB Technologies

Corporation, PPN7PA12C1

Channel 4: Motor current

Figure 7. Motor Startup With No Load