MLX16305 Datasheet, PDF (10/29 Pages) Melexis Microelectronic Systems – Interlock switch sensor interface IC

MLX16305
Interlock switch sensor interface IC
8.6. ENCODER: Internal Digital Signals
• MuxSenseLatched[0:2] signals are defined by the MUX_SENSE and ENABLE inputs. It is used
for 3 purposes:
o to go to OVERTEMP measurement mode
o to set MEAS_OUT high impedant
o to select the channel that is to be supplied with Vref.
MuxSenseLatched = MUX_SUP if ENABLE = 1
The standard relation between MUX_SENSE, ENABLE and MuxSenseLatched can be viewed as
a latch that is controlled by ENABLE:
o ENABLE = 0
Ö then the latch is transparent: MuxSenseLatched == MUX_SENSE
o ENABLE = 1
Ö then the latch is closed: MUX_SENSE can be changed without influencing
MuxSenseLatched.
MUX_SENSE[0:2]
ENABLE
OVERTEMP
Z
MuxSenseLatched[0:2]
MUX_SUP[0:2]
MUX_SUP[0:2]
MUX_SUP == MuxSenseLatched AND ENABLE
The MUX_SUP[0:2] signals control the multiplexer that selects the channel on which the voltage
regulator will force Vref.
1. Apply on MUX_SENSE the value of the channel that should be supplied while ENABLE is
low.
2. Then switch ENABLE high to latch this state into MuxSenseLatched.
3. As long as ENABLE stays high the selected SENSE pin will be supplied with the VREF
voltage.
4. In the mean time MUX_SENSE may change. This allows diagnostics for shorts between
SENSE pins. One channel can be supplied with Vref and another can be sensed.
(MUX_SUP ≠ MUX_SENSE)
5. As soon as ENABLE goes low again, MUX_SUP is reset to 000b, hence disabling every
channel. The weak pull down on every SENSE pin will then pull VSENSE down.
OVERTEMP (Dominant setting):
In order to set OVERTEMP = 1 MuxSenseLatch[0:2] has to be set to 111b.
o When ENABLE = 0, the Overtemp condition can be read out on the MEAS_OUT pin by
setting MUX_SENSE = 111b.
o When ENABLE turns = 1 MuxSenseLatched remains = 111b. Changes on
MUX_SENSE[0:2] are neglected (= don’t care).
3901016305
Rev. 005
Page 10 of 29
Data Sheet
Oct/06