X40231 Datasheet, PDF (24/36 Pages) Intersil Corporation – Triple Voltage Monitors, POR, 2 kbit EEPROM MEMORY, and Single/Dual DCP

X40231, X40233, X40235, X40237, X40239
For example, the desired threshold for V_TRIP2 is set to
3.0 V, and a test voltage of 3.4 V was applied to the input
pin V2MON (after applying power to V_CC). The input volt-
age is decreased, and found to trip the associated output
level of pin V2FAIL from a LOW to a HIGH, when
V2MON 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 program-
ming 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 cal-
culated 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 pro-
grammed voltage, minus the last previously calculated
error. Therefore, we must apply V_TRIP2 = 2.91 V to pin
V2MON and execute the programming sequence (See
"Setting a Higher V_TRIPx Voltage (x = 1,2,3)").
Using this process, the desired accuracy for a particu-
lar V_TRIPx threshold may be attained using a succes-
sive 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
Power-down
MDE⁺
Desired Value
MDE^–
Acceptable
Error Range
Error = Actual – Desired
New Vx applied =
Old Vx applied - | Error |
Execute
Reset V_TRIPx
Sequence
Ramp up 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)
24
FN8115.0
April 11, 2005