IC-PV Datasheet, PDF (18/28 Pages) IC-Haus GmbH – BATTERY-BUFFERED HALL MULTITURN ENCODER

iC-PV
BATTERY-BUFFERED HALL MULTITURN ENCODER
SUPPLY SWITCH AND BATTERY MONITORING
Rev E2, Page 18/28
To retain and acquire the absolute position even on
main power failure, the iC-PV switches from VDD to
a battery supply on pin VBAT. The switching point lies
just below 3 V. So if the main supply voltage on VDD
drops below 3 V, the internal circuitry will be powered
by VBAT instead of VDD.
The supply switch has a build in hysteresis. The thresh-
old voltages are defined in the electrical characteristics
section named V_off (Item No. 402), i.e. the voltage at
which the circuit switches from VDD supply to VBAT
supply and V_on (Item No. 401), the voltage at which the
circuit switches back to VDD.
Depending on the used energy storage, e.g. a 3.6 V
battery with 1 Ah capacity, the device can operate for
several years. The iC-PV monitors the voltage at pin
VBAT to detect a low battery voltage. If it drops below
a defined error threshold voltage (Item No. 404), an
error is generated and signalized via pin NERR and as
error bit in the SSI communication protocol. The battery
monitoring function can be enabled/disabled with con-
figuration parameter EN_BAT_MON as show in Table
18.
EN_BAT_MON Addr. 0x03; bit 6
Code
Function
0
Battery monitoring off
1
Battery monitoring on
Table 18: Enable or disable the internal battery monitor.
BIAS AND OSCILLATOR CALIBRATION
The bias current for the internal oscillator can be con-
figured with the configuration parameter IBIAS. An in-
crease or decrease in bias current will directly influence
the oscillator frequency. The bias current should be
calibrated at the typical battery supply voltage so that
the frequency of the oscillator is around 8.5 kHz (see
Item No. 301). The clock frequency is observable in
the dedicated calibration mode. The calibration mode is
entered by configuring the EN_ERR parameter to "01"
(see Table 15). The oscillator clock is then output on
pin DI_P1.
IBIAS
Code
100
101
110
111
000
001
010
011
Addr. 0x03; bit 2:0
Frequency change
+20 %
+10 %
0%
-10 %
-20 %
-30 %
-40 %
-50 %
Table 19: Bias current; oscillator frequency calibration.