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FN8100.4
May 18, 2006
Figure 5. Set VTRIP Level Sequence (VCC = desired VTRIP value)
Resetting the VTRIP Voltage
This procedure is used to set the VTRIP to a “native”
voltage level. For example, if the current VTRIP is 4.4V
and the new VTRIP must be 4.0V, then the VTRIP must
be reset. When VTRIP is reset, the new VTRIP is some-
thing less than 1.7V. This procedure must be used to
set the voltage to a lower value.
To reset the new VTRIP voltage, apply more than 5.5V
to the VCC pin and tie the RESET pin to the
programming voltage VP. Then write 00h to address
03h. The stop bit of a valid write operation initiates the
VTRIP programming sequence. Bring RESET to VCC to
complete the operation. Note: this operation takes up
to 10 milliseconds to complete and also writes 00h to
address 03h of the EEPROM array.
For best accuracy in setting VTRIP, it is advised that
the following sequence be used.
1.Program VTRIP as above.
2.Measure resulting VTRIP by measuring the VCC
value where a RESET occurs. Calculate Delta =
(Desired – Measured) VTRIP value.
3.Perform a VTRIP program using the following formula
to set the voltage of the RESET pin:
VRESET = (Desired Value – Delta) + 0.025V
Figure 6. Reset VTRIP Level Sequence
SCL
SDA
01h
RESET
VP = 15V
00h
01 2 3 45 67
0 1 2 3 45 67
01 2 3 4 5 6 7
AEh
00h
VCC
Note: BP0, BP1, BP2 must be disabled.
0 1 2 3 45 67
SCL
SDA
AEh
01 2 3 4 5 6 7
03h
RESET
VP = 15V
00h
0 1 2 3 45 67
01 2 3 4 5 6 7
00h
VCC
Note: BP0, BP1, BP2 must be disabled.
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