DRV8802-Q1_15 Datasheet, PDF (13/26 Pages) Texas Instruments – DRV8802-Q1 Automotive DC Motor-Driver IC

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DRV8802-Q1
SLVSCI2A – JUNE 2014 – REVISED JUNE 2014
8 Application and Implementation
8.1 Application Information
The DRV8802-Q1 device is used in medium voltage brushed-DC motor control applications.
8.2 Typical Application
V_M
+
100 µF
CP1
0.01 µF _CP2
DRV8802-Q1 GND
BI1
VCP
BI0
0.1 µF
1 M
0.01 µF _VMA
AI1
AOUT1
+
400 m
ISENA
AI0
BPHASE
AOUT2
BENBL
400 m
BOUT2
ISENB
AENBL
APHASE
BOUT1
DECAY
V3P3OUT
0.1 µF
10 k
30 k
VMB
AVREF
BVREF
GND
nFAULT
nSLEEP
nRESET
V3P3OUT
V3P3OUT
10 k
V3P3OUT
0.47 µF
Figure 7. Typical Application Diagram
8.2.1 Design Requirements
The example supply for this design is V_(VMx) = 18 V.
8.2.2 Detailed Design Procedure
8.2.2.1 Drive Current
The current path is through the high-side sourcing DMOS driver, motor winding, and low-side sinking DMOS
power driver. Power dissipation I²R losses in one source and sink DMOS driver are 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)
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