DRV8301_12 Datasheet, PDF (21/26 Pages) Texas Instruments – Three Phase Pre-Driver with Dual Current Shunt Amplifiers and Buck Regulator

DRV8301
www.ti.com
SLOS719 – AUGUST 2011
Over Current Adjustment
When external MOSFET is turned on, the output current flows the MOSFET, which creates a voltage drop V_DS.
The overcurrent protection event will be enabled when the V_DS exceeds a pre-set value IOC. The OC tripped
value can be programmed through SPI command. Assuming the on resistance of MOSFET is R_DS(on), the Vds
can be calculated as:
V_DS = I_OC × R_DS(on)
V_DS is measured across the SL_x and SH_x pins for the low-side MOSFET. For the high-side MOSFET, V_DS is
measured across PVDD1 (internally) and SH_x. Therefore, it is important to limit the ripple on the PVDD1 supply
for accurate high-side current sensing.
It is also important to note that there can be up to a 20% tolerance across channels for the OC trip point. This is
meant for protection and not to be used for regulating current in a motor phase.
Control Bit (D6–D10) (0xH)
Vds (V)
Control Bit (D6–D10) (0xH)
Vds (V)
Control Bit (D6–D10) (0xH)
Vds (V)
Code Number (0xH)
Vds (V)
0
0.060
8
0.155
16
0.403
24
1.043
Table 9. OC_ADJ_SET Table
1
0.068
9
0.175
17
0.454
25
1.175
2
0.076
10
0.197
18
0.511
26
1.324
3
0.086
11
0.222
19
0.576
27
1.491
4
0.097
12
0.250
20
0.648
28
1.679
5
0.109
13
0.282
21
0.730
29
1.892
6
0.123
14
0.317
22
0.822
30
2.131
7
0.138
15
0.358
23
0.926
31
2.400
Copyright © 2011, Texas Instruments Incorporated
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