DRV8804_16 Datasheet, PDF (12/27 Pages) Texas Instruments – Quad Serial Interface Low-Side Driver IC

DRV8804
SLVSAW4F – JULY 2011 – REVISED DECEMBER 2015
www.ti.com
8.2.2 Detailed Design Procedure
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 starts from the supply V_M, 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)
The DRV8804 has been measured to be capable of 1.5-A Single Channel or 800-mA Four Channels with the
DW package and 2-A Single Channel or 1-A Four Channels with the PWP package at 25°C on standard FR-4
PCBs. The maximum RMS current will vary based on PCB design and the ambient temperature..
8.2.3 Application Curves
Figure 8. Current Ramp With a 16-Ω, 1-mH, R_L Load and
V_M = 8.2 V
Figure 9. Current Ramp With a 16-Ω, 1-mH R_L Load and V_M
= 30 V
Figure 10. OCP With V_M = 8.2 V and OUT1 Shorted to V_M
Figure 11. OCP Separated by t_RETRY With V_M = 8.2 V and
OUT1 Shorted to V_M
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