Texas Instruments DRV8301-RM48-KIT - RM48 Hercules Safety MCU Motor Control Kit DRV8301-RM48-KIT DRV8301-RM48-KIT 데이터 시트
제품 코드
DRV8301-RM48-KIT
SLOS719B – AUGUST 2011 – REVISED AUGUST 2013
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.
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.
meant for protection and not to be used for regulating current in a motor phase.
Table 9. OC_ADJ_SET Table
Control Bit (D6–D10) (0xH)
0
1
2
3
4
5
6
7
Vds (V)
0.060
0.068
0.076
0.086
0.097
0.109
0.123
0.138
Control Bit (D6–D10) (0xH)
8
9
10
11
12
13
14
15
Vds (V)
0.155
0.175
0.197
0.222
0.250
0.282
0.317
0.358
Control Bit (D6–D10) (0xH)
16
17
18
19
20
21
22
23
Vds (V)
0.403
0.454
0.511
0.576
0.648
0.730
0.822
0.926
Code Number (0xH)
24
25
26
27
28
29
30
31
Vds (V)
1.043
1.175
1.324
1.491
1.679
(1)
1.892
(1)
2.131
(1)
2.400
(1)
(1)
Do not use settings 28, 29, 30, 31 for V
DS
sensing if the IC is expected to operate in the 6V – 8V range.
Copyright © 2011–2013, Texas Instruments Incorporated
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