
preliminary
preliminary
iC-PVS
LINEAR/OFF-AXIS
BATTERY-BUFFERED ABSOLUTE POSITION HALL SENSOR
Rev A2, Page 29/51
PERIOD COUNTER
As long as iC-PVS is started- and powered-up correctly
(i.e. via battery or main supply), iC-PVS will perma-
nently track the absolute position. This is done by
counting the magnetic periods of the target and dividing
them into revolution and period counts per revolution.
The internal revolution counter is 40 bits wide and thus
can count up to 2
40
−
1 revolutions. The serial interface
output bit width is defined by RCL_ADI, i.e. 2
MT
_
BW
−
1
revolutions can be read-out. Additionally, a 16 bit pe-
riod counter is implemented to support systems with
multiple magnetic periods per mechanical revolution,
e.g. magnetic pole wheels. Please note, that there is
no revolution counter overflow handling in positive or
negative direction.
Position Preload
Both, the revolution and period counter can be
preloaded with a position defined by configuration pa-
rameters RCTR_PREL (Table 22) and PCTR_PREL
(Table 23). These two configuration parameters are
secured by an eight bit checksum named CRC_PREL.
RCTR_PREL
(7:0)
Addr. 0x1A;
Reset:
RCTR_PREL
(15:8)
Addr. 0x1B;
0
RCTR_PREL
(23:16)
Addr. 0x1C;
RCTR_PREL
(31:24)
Addr. 0x1D;
RCTR_PREL
(39:32)
Addr. 0x1E;
Code
Value
0x0000000000
0
0x0000000001
1
...
...
0x00000000FF
255
...
...
0xFFFFFFFFFF
2
40
−
1
Table 22: Revolution Counter Preload Value
PCTR_PREL(7:0)
Addr. 0x18;
Reset:
PCTR_PREL(15:8)
Addr. 0x19;
0x0000
Code
Value
0x0000
0
0x0001
1
...
...
0x00FF
255
...
...
0xFFFF
65535
Table 23: Period Counter Preload Value
SUPPLY SWITCH AND MONITORING
To retain and track the absolute position on main power
shutdown, iC-PVS monitors VDD and switches in be-
tween VDD and battery supply on pin VBAT automat-
ically. The switching points are defined in Elec. Char.
406 and 405. If the main supply voltage on VDD drops
below the Voff threshold, the internal circuitry is pow-
ered by VBAT instead of VDD. To save power, the
analog signal output is inactive in battery mode. If the
voltage at VDD rises above the Von threshold, the cir-
cuitry is powered via the VDD pin again and the analog
signal output is active.
The supply switching features a built-in hysteresis.
Please see Elec. Char. 407.
BAT_MON: Battery Monitor Enable
The iC-PVS monitors the voltage at pin VBAT to detect a
low battery voltage condition. If the supply drops below
the error threshold
V
err
voltage (Elec. Char. 408), an er-
ror is generated and signalized at pin NERR and by the
error bit in the serial protocol and status register. The
battery monitoring function can be enabled/disabled by
the configuration parameter BAT_MON (Table 24).
BAT_MON(1:0)
Addr. 0x08; bit 4:3
reset: 00
Code
Battery Monitoring
00
disabled
01
during battery supply only
10
during VDD supply only
11
Permanently enabled
Table 24: Battery Monitor Enable
This configuration option is useful to disable battery
monitoring to save battery power. If enabled, the battery
monitoring draws current from the battery. If disabled,
no additional current is drawn from the battery. The
current consumption of the battery monitoring feature
can be configured by parameter MON_FRQ (Table 26).
Additionally, if the battery monitoring feature is enabled
by parameter BAT_MON, an early battery warning mes-