MAX1718 Maxim, MAX1718 Datasheet - Page 23

• Manufacturer Part Number: MAX1718
• Description: Notebook CPU Step-Down Controller for Intel Mobile Voltage Positioning IMVP-II
• Manufacturer: Maxim

voltage. If the output is more than 2V, OVP is triggered
and the circuit shuts down. The DL low-side gate-driver
output is then latched high until SKP/SDN is toggled or
V
synchronous-rectifier MOSFET with 100% duty and, in
turn, rapidly discharges the output filter capacitor and
forces the output to ground. If the condition that caused
the overvoltage (such as a shorted high-side MOSFET)
persists, the battery fuse will blow. DL is also kept high
continuously when V
shutdown mode (Table 6).
Overvoltage protection can be defeated with a logic
high on OVP or through the NO FAULT test mode (see
the NO FAULT Test Mode section).
Figure 14. Using the ZMODE Multiplexer
CC
power is cycled below 1V. This action turns on the
Notebook CPU Step-Down Controller for Intel
ADDRESS
SMBUS
CPU
CLOCK
DATA
ADD0
ADD1
______________________________________________________________________________________
1
1
1
1
1
CC
MAX1609
R
UVLO is active, as well as in
R
Mobile Voltage Positioning (IMVP - II)
3.3V
0
1
0
1
0
3.3V
R
R
R = 100kΩ
SMBSUS
R
R
R
R
R
The output UVP function is similar to foldback current
limiting, but employs a timer rather than a variable cur-
rent limit. If the MAX1718 output voltage is under 70% of
the nominal value, the PWM is latched off and won’t
restart until V
gled. To allow startup, UVP is ignored during the under-
voltage fault-blanking time (the first 256 cycles of the
slew rate after startup).
UVP can be defeated through the NO FAULT test mode
(see the NO FAULT Test Mode section).
VID4
VID3
VID2
VID1
VID0
CC
3.3kΩ
Output Undervoltage Shutdown
MAX1718
ZMODE
power is cycled or SKP/SDN is tog-
GMUXSEL
1nF
23