DRV8801A-Q1 Datasheet, PDF (14/24 Pages) Texas Instruments – DMOS Full-Bridge Motor Drivers

DRV8801A-Q1
SLVSC79C – JUNE 2014 – REVISED JULY 2016
www.ti.com
Typical Application (continued)
8.2.1 Design Requirements
The example supply voltage for this design is V_BB = 18 V.
8.2.2 Detailed Design Procedure
8.2.2.1 Drive Current
This current path is through the high-side sourcing DMOS driver, motor winding, and low-side sinking DMOS
driver. Power dissipation I²R loses in one source and one sink DMOS driver, as shown in Equation 2.
P_D = I² (r_DS(on)Source + r_DS(on)Sink )
(2)
8.2.2.2 Slow-Decay SR (Brake Mode)
In slow-decay mode, both low-side sinking drivers turn on, allowing the current to circulate through the low side
of the H-bridge (two sink drivers) and the load. Power dissipation I²R loses in the two sink DMOS drivers as
shown in Equation 3
P_D = I² (2 ´ r_DS(on)Sink )
(3)
8.2.3 Application Curves
OUTA
OUTB
I_O
OUTA
OUTB
I_O
Figure 7. 75% Drive, 25% Slow Decay; ƒ_(PWM) = 5 kHz
Figure 8. 75% Drive, 25% Fast Decay; ƒ_(PWM) = 5 kHz
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