X40231 Datasheet, PDF (23/36 Pages) Intersil Corporation – Triple Voltage Monitors, POR, 2 kbit EEPROM MEMORY, and Single/Dual DCP

X40231, X40233, X40235, X40237, X40239
Setting a Higher V_TRIPx Voltage (x = 1,2,3)
To set a V_TRIPx threshold to a new voltage which is
higher than the present threshold, the user must apply
the desired V_TRIPx threshold voltage to the correspond-
ing input pin (V_CC, V2MON or V3MON). Then, a pro-
gramming voltage (Vp) must be applied to the WP pin
before a START condition is set up on SDA. Next, issue
on the SDA pin the Slave Address A0h, followed by the
Byte Address 01h for V_TRIP1, 09h for V_TRIP2, and 0Dh
for V_TRIP3, and a 00h Data Byte in order to program
V_TRIPx. The STOP bit following a valid write operation
initiates the programming sequence. Pin WP must then
be brought LOW to complete the operation (See Figure
23). The user does not have to set the WEL bit in the
CR register before performing this write sequence.
Setting a Lower V_TRIPx Voltage (x = 1,2,3).
In order to set V_TRIPx to a lower voltage than the
present value, then V_TRIPx must first be “reset” accord-
ing to the procedure described below. Once V_TRIPx
has been “reset”, then V_TRIPx can be set to the desired
voltage using the procedure described in “Setting a
Higher V_TRIPx Voltage”.
Resetting the V_TRIPx Voltage (x = 1,2,3).
To reset a V_TRIPx voltage, apply the programming volt-
age (Vp) to the WP pin before a START condition is
set up on SDA. Next, issue on the SDA pin the Slave
Address A0h followed by the Byte Address 03h for
V_TRIP1, 0Bh for V_TRIP2, and 0Fh for V_TRIP3, followed
by 00h for the Data Byte in order to reset V_TRIPx. The
STOP bit following a valid write operation initiates the
programming sequence. Pin WP must then be brought
LOW to complete the operation (See Figure 23). The
user does not have to set the WEL bit in the CR regis-
ter before performing this write sequence.
After being reset, the value of V_TRIPx becomes a nomi-
nal value of 1.7V.
V_TRIPx Accuracy (x = 1,2,3).
The accuracy with which the V_TRIPx thresholds are set,
can be controlled using the iterative process shown in
Figure 24.
If the desired threshold is less that the present thresh-
old voltage, then it must first be “reset” (See "Resetting
the V_TRIPx Voltage (x = 1,2,3).").
The desired threshold voltage is then applied to the
appropriate input pin (V_CC, V2MON or V3MON) and
the procedure described in Section “Setting a Higher
V_TRIPx Voltage“ must be followed.
Once the desired V_TRIPx threshold has been set, the
error between the desired and (new) actual set thresh-
old can be determined. This is achieved by applying
V_CC to the device, and then applying a test voltage
higher than the desired threshold voltage, to the input
pin of the voltage monitor circuit whose V_TRIPx was
programmed. For example, if V_TRIP2 was set to a
desired level of 3.0 V, then a test voltage of 3.4 V may
be applied to the voltage monitor input pin V2MON. In
the case of setting of V_TRIP1 then only V_CC need be
applied. In all cases, care should be taken not to
exceed the maximum input voltage limits.
After applying the test voltage to the voltage monitor
input pin, the test voltage can be decreased (either in
discrete steps, or continuously) until the output of the
voltage monitor circuit changes state. At this point, the
error between the actual/measured, and desired
threshold levels is calculated.
V_P
WP
SCL
SDA
0 1 23 4 56 7
0 1 23 4 56 7
0 1 23 4 56 7
00h ^†
A0h^†
03h^† Resets VTRIP1
Data Byte
S
T
0Bh^† Resets VTRIP2
A
R
0Fh^† Resets VTRIP3
T
† _{All others Reserved.}
Figure 23. Resetting the V_TRIPx Level
23
FN8115.0
April 11, 2005