X9520_07 Datasheet, PDF (18/29 Pages) Intersil Corporation – Triple DCP, POR, 2kbit EEPROM Memory, Dual Voltage Monitors

X9520
applying power to V1/VCC). The input voltage is decreased,
and found to trip the associated output level of pin V2RO from a
LOW to a HIGH, when V2 reaches 3.09 V. From this, it can be
calculated that the programming error is 3.09 - 3.0 = 0.09 V.
If the error between the desired and measured V_TRIPx is
less than the maximum desired error, then the programming
process may be terminated. If however, the error is greater
than the maximum desired error, then another iteration of the
V_TRIPx programming sequence can be performed (using the
calculated error) in order to further increase the accuracy of
the threshold voltage.
If the calculated error is greater than zero, then the V_TRIPx
must first be “reset”, and then programmed to the a value equal
to the previously set V_TRIPx minus the calculated error. If it is
the case that the error is less than zero, then the V_TRIPx must
be programmed to a value equal to the previously set V_TRIPx
plus the absolute value of the calculated error.
Continuing the previous example, we see that the calculated
error was 0.09V. Since this is greater than zero, we must first
“reset” the V_TRIP2 threshold, then apply a voltage equal to the
last previously programmed voltage, minus the last previously
calculated error. Therefore, we must apply V_TRIP2 = 2.91 V to
pin V2 and execute the programming sequence.
Using this process, the desired accuracy for a particular
V_TRIPx threshold may be attained using a successive
number of iterations.
V_TRIPx Programming
Note: X = 1,2,3.
Let: MDE = Maximum Desired Error
New Vx applied =
Old Vx applied + | Error |
NO
Desired V_TRIPx <
present value?
YES
Execute
V_TRIPx Reset
Sequence
Set Vx = desired V_TRIPx
Execute
Set Higher V_TRIPx
Sequence
MDE⁺
Desired Value
MDE^–
Acceptable
Error Range
Error = Actual - Desired
New Vx applied =
Old Vx applied - | Error |
Apply VCC & Voltage
> Desired V_TRIPx to Vx
Execute
Reset V_TRIPx
Sequence
Decrease Vx
NO
Output
switches?
YES
Error < MDE^–
-
Actual V_TRIPx
Desired V_TRIPx
= Error
Error >MDE⁺
| Error | < | MDE |
DONE
FIGURE 24. V_TRIPx SETTING/RESET SEQUENCE (X = 1,2,3)
18
FN8206.2
August 20, 2007