DRV8803_16 Datasheet, PDF (10/26 Pages) Texas Instruments – Quad Low-Side Driver IC

DRV8803
SLVSAW5C – JULY 2011 – REVISED NOVEMBER 2015
8 Application and Implementation
www.ti.com
NOTE
Information in the following applications sections is not part of the TI component
specification, and TI does not warrant its accuracy or completeness. TI’s customers are
responsible for determining suitability of components for their purposes. Customers should
validate and test their design implementation to confirm system functionality.
8.1 Application Information
The DRV8803 device can be used to drive one unipolar stepper motor.
8.2 Typical Application
VM
0.1 µF
+
100 µF
M
+–
1 _VM
nFAULT ²⁰
2 _VCLAMP
NC ¹⁹
3
OUT 1
18
IN1
4
OUT 2
17
IN2
5
GND
16
GND
6 _GND DRV8803 _GND 15
7 _GND
GND ¹⁴
8
OUT 3
13
IN3
9
OUT 4
12
IN4
10
nENBL
11
RESET
Figure 7. Typical Application Schematic
8.2.1 Design Requirements
Table 1 lists the design parameters for this design example.
DESIGN PARAMETER
Supply Voltage
Motor Winding Resistance
Motor Full Step Angle
Motor Rated Current
PWM frequency
8.2.2 Detailed Design Procedure
Table 1. Design Parameters
REFERENCE
V_M
R_L
θ_step
I_RATED
f_PWM
EXAMPLE VALUE
24 V
7.4 Ω/phase
1.8°/step
0.75 A
31.25 kHz
8.2.2.1 Motor Voltage
The motor voltage to use will depend on the ratings of the motor selected and the desired torque. A higher
voltage shortens the current rise time in the coils of the stepper motor allowing the motor to produce a greater
average torque. Using a higher voltage also allows the motor to operate at a faster speed than a lower voltage.
8.2.2.2 Drive Current
The current path is starts from the supply VM, moves through the inductive winding load, and low-side sinking
NMOS power FET. Power dissipation losses in one sink NMOS power FET are shown in Equation 1.
P = I² × R_DS(on)
(1)
10
Submit Documentation Feedback
Copyright © 2011–2015, Texas Instruments Incorporated
Product Folder Links: DRV8803