User Guide
25 of 46
Rev. 1.0
2022-03-09
48V Battery Switch Reference Design
R 48V BATT Switch10
System and functional description
Command
Description
Setting Value
0
cross control deactivated
1
cross control activated
csag
Current sense amplifier gain
0
10 V/V
1
15 V/V
2
20 V/V
3
25 V/V
4
31.5 V/V
5
35 V/V
6
40 V/V
7
47.7 V/V
cshs
Current sense position
0
shunt on low side
1
shunt on high side
csld
Current sense output load
0
< 100 pF
1
> 100 pF
octh
Overcurrent detection threshold
0
VDD/2 ± 0.1 VDD
1
VDD/2 ± 0.2 VDD
2
VDD/2 ± 0.25 VDD
3
VDD/2 ± 0.3 VDD
The actual overcurrent threshold value in Ampere is depending on the setting of the current sense amplifier
gain (csag) and the overcurrent detection threshold setting (octh). Table 8 shows the resulting values for a
50 µ
W
shunt resistor. The default factory setting is csag 6 and octh 2 which amounts in an overcurrent
threshold of 413 A.
Table 8
Overcurrent threshold values vs. csag and octh setting
csag
0
csag
1
csag
2
csag
3
csag
4
csag
5
csag
6
csag
7
octh
0
660 A
440 A
330 A
264 A
210 A
189 A
165 A
138 A
octh
1
1320 A
880 A
660 A
528 A
419 A
377 A
330 A
277 A
octh
2
1650 A
1100 A
825 A
660 A
524 A
471 A
413 A
346 A
octh
3
1980 A
1320 A
990 A
792 A
629 A
566 A
495 A
415 A
Precharge time
When the switch is turned on with BUTTON1 on the microcontroller board or with the “on” command, a
precharge pulse is applied via channel B before engaging the main switch (channel A). The precharge time can
be set with the command “prt”, followed by the pulse length in milliseconds.
