MLX16305 Datasheet, PDF (11/29 Pages) Melexis Microelectronic Systems – Interlock switch sensor interface IC

MLX16305
Interlock switch sensor interface IC
Z or HIGH IMPEDANT (Dominant setting):
In order to set Z = 1 MuxSenseLatch [0:2] has to be set to 000b.
o When ENABLE = 0, MUX_SENSE has to be set to 000b.
o When ENABLE turns = 1 MuxSenseLatched remains = 000b. Changes on
MUX_SENSE[0:2] are neglected (= don’t care).
Mind that both OVERTEMP=1 or Z=1, are dominant settings on MEAS_OUT. This implies that
any changes on VI_CTRL and MUX_SENSE[0:2] are not visible.
MIND.
Do not confuse the latch with a flip-flop which is only sensitive during rising edge of the Enable. The latch
is transparent for input changes whilst ENABLE is low, not only during the rising edge.
Timing diagram
12
34 5
6
78
9
MUXSENSE[0:2] 000 100 000 001
010
ENABLE
10
111
MuxSenseLatched[0:2]
MUX_SUP[0:2]
OVERTEMP
Z
000
001
010
111
000
000 001 000 010 000 111
The above timing diagram shows how the inputs are converted internally:
n In case of multiplexing 2 or more devices, the system should start up with MUXSENSE[0:2] and
ENABLE = 0 for all devices in order to avoid conflicts on the MEASOUT output.
o Changes on MUXSENSE are not seen by the device as long as ENABLE is kept high.
p In order to switch from one device to another device all MUXSENSE inputs are reset to 000b.
q In order to start switch MUXSENSE at r, all other devices should have set ENABLE high.
r
a. In Current Mode Channel 0 is selected, VMEASOUT = VMEAS(offset)as long as
ENABLE is low.
b. In Voltage mode, no channel is selected, so VMEAS remains 0V.
s
a. In CM the voltage regulator supplies current to channel 0 (Isense0). Isense0 is copied
onto RREF, and can be calculated from VMEASOUT.
b. In VM the voltage regulator supplies Vref to channel 0 (Vsense0). Vsense0 is copied on
VMEASOUT.
t ENABLE remains high
a. In CM changes on MUXSENSE are neglected (don’t care)
b. In VM, the voltage is measured on channel 1, which has its weak pull down active. If
Vsense1 > 0V then a short to Channel 1 is found.
u ENABLE goes low, disabling all channels while channel 1 is selected. See r
v ENABLE goes high and low again while MUXSENSE remains unchanged.
a. In CM Isense1 can be measured while ENABLE is high.
b. In VM channel 1 is supplied with Vref and the resulting Vsense1 is copied to VMEASOUT
w MUXSENSE=111b displays the OVERTEMP condition on the MEASOUT pin.
3901016305
Rev. 005
Page 11 of 29
Data Sheet
Oct/06