iC-JRX
µP INTERFACE WITH 2×4 24V HIGH-SIDE DRIVERS
Rev A1, Page 21/23
Low voltage detection
When the supply voltage at VCC is switched on, the output transistors are only released by the low voltage
detector after the power-on enable VCCon has been reached. Should the supply voltage drop to VCCoff during
operation, the I/O stages are disabled, i.e. the output transistors are turned off and the device reset (signal VOK).
If the supply voltage should then rise to VCCon, iC-JRX is in its reset state.
Identification of the device
An identification code has been introduced to enable identification of device iC-JRX. Bit pattern ‘000000’b can
be read out under address 5.
Reset
A reset (RESN= 0) sets the register entries to the reset values given in the tables. The output transistors and the
current sources in the I/O stages are shutdown and all stages switched to input mode.
Operation without the BLFQ signal
Should no clock signal be available at pin BLFQ, iC-JRX can generate the flash pulse internally from the clock
signal at pin CLK. To this end, NOBLFQ in control word 3 must be set to ‘1’. The flash period is then calculated
from the clocking pulse at CLK by division by 219.
Operation without the CLK signal
iC-JRX is operable without a clocking pulse at the CLK pin. With NOCLK in control word 3 the clocked filtering
for the I/O signals and overcurrent messaging is deactivated. The device remains fully functional with one
exception; the PWM cannot be activated, as this is dependent on CLK.
The same behavior can be obtained by setting BYPH and BYPL in control word 1 together with BYPSCF in
control word 4; all filters are avoided by way of a bypass circuit. This has one disadvantage, namely that
interferences in the load lines, for example, can lead to the unwanted display of interrupts.
Forced shutdown of output stages
The output stages can be forcibly shutdown at input POE. A ‘1’ enables logic access to the drivers; an ‘0’
disables this. With this, a processor-independent watchdog can lock the outputs in the event of error, for
example. An integrated pull-down resistor increases safety.
ICHAUS [ IC-HAUS GMBH ]
