Data Sheet

12
DRV8835
SLVSB18G –MARCH 2012 –REVISED MAY 2016 www.ti.com
Product Folder Links: DRV8835
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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 V
CC
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