AMIS-30421 Datasheet, PDF (37/41 Pages) ON Semiconductor – Micro-Stepping Stepper Motor Bridge Controller

AMIS−30421
Predriver Register 4 (PDRV4)
Predriver Register 4 is located at address 0x0D and can be used to set the current source for the gate discharge of the external
MOSFET’s (see Figure 11).
Table 33. PREDRIVER REGISTER 4
Address
0x0D
Access
Reset
Data
Bit 7
R/W
0
Predriver Register 4 (PDRV4)
Bit 6
Bit 5
Bit 4
R/W
R/W
R/W
1
0
0
TOP_IOFF[3:0]
Bit 3
R/W
0
Bit 2
Bit 1
R/W
R/W
1
0
BOT_IOFF[3:0]
Bit 0
R/W
0
Table 34. PREDRIVER REGISTER 4 PARAMETERS
Parameter
Value
Value
Description
Info
TOP_IOFF[3:0]
xxxx
Current source
value
Defines the current source for the external top MOSFET’s during
t_off. Current source can be calculated as next:
10.5 mA + (PDRV4[7:4] x 7 mA)
p13
BOT_IOFF[3 :0]
xxxx
Current source
value
Defines the current source for the external bottom MOSFET’s dur-
ing t_off. Current source can be calculated as next:
10.5 mA + (PDRV4[3:0] x 7 mA)
p13
Predriver Register 5 (PDRV5)
Predriver Register 5 is located at address 0x0E and can be used to set t₂ (see Figure 11).
Table 35. PREDRIVER REGISTER 5
Address
0x0E
Access
Reset
Data
Bit 7
R/W
0
−
Predriver Register 5 (PDRV5)
Bit 6
Bit 5
Bit 4
R/W
R/W
R/W
1
0
0
TOP_t2[2:0]
Bit 3
R/W
0
−
Bit 2
R/W
1
Bit 1
R/W
0
BOT_t2[2:0]
Bit 0
R/W
0
Table 36. PREDRIVER REGISTER 5 PARAMETERS
Parameter
Value
Value
Description
Info
000
1.25 ms
001
1.75 ms
010
2.25 ms
011
2.75 ms
TOP_t2[2:0]
100
3.25 ms
Defines the switch on duration t₂ for the external top MOSFET’s.
p13
101
3.75 ms
110
4.25 ms
111
4.75 ms
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