MAX16046_09 Datasheet, PDF (61/70 Pages) Maxim Integrated Products – 12-Channel/8-Channel EEPROM-Programmable System Managers with Nonvolatile Fault Registers

12-Channel/8-Channel EEPROM-Programmable
System Managers with Nonvolatile Fault Registers
V_IN
V_CC
C
MAX16046
MAX16048
If more than six series-pass MOSFETs are required for
an application, additional series-pass p-channel
MOSFETS may be connected to outputs configured as
active-low open drain (Figure 20). Connect a pullup
resistor from the gate to the source of the MOSFET, and
ensure the absolute maximum ratings of the
MAX16046/MAX16048 are not exceeded.
V_IN
V_OUT
GND
MON_
EN_OUT_ INS_
Figure 18. Power Circuit for Shutdown During Fault Conditions
Driving High-Side MOSFET Switches
The MAX16046/MAX16048 use external n-channel
MOSFET switches for voltage tracking applications. To
configure the part for closed-loop voltage tracking
using series-pass MOSFETs, configure up to four of the
programmable outputs (EN_OUT1–EN_OUT4) of the
MAX16046/MAX16048 as closed-loop tracking outputs
and configure up to four of the GPIOs as sense-return
inputs (INS1–INS4). Connect the EN_OUT_ output to
the gate of an n-channel MOSFET, connect the source
of the MOSFET to the INS_ feedback input, and monitor
the drain side of the MOSFET with the corresponding
MON_ input (see Figure 19). Both the input and the out-
put must be assigned to the same slot (see the
Closed–Loop Tracking section). Configure the power-
up and power-down slew rates in the configuration reg-
isters. To provide additional control over power-down,
enable the internal 100Ω pulldown resistors on the INS_
connections.
Up to six of the programmable outputs (EN_OUT1–
EN_OUT6) of the MAX16046/MAX16048 may be config-
ured as charge-pump outputs. In this case, they can
drive the gates of series-pass n-channel MOSFETS with-
out closed-loop tracking functionality. When configured
in this way, these outputs act as simple power switches
to turn on the voltage supply rails. Approximate the slew
rate, SR, using the following formula:
( ) ^{SR =}
I_CP
C_GATE + C_EXT
ADC MUX
LOGIC
REFERENCE
RAMP
GATE
DRIVE
V_{TH_PG}
100Ω
Figure 19. Closed-Loop Tracking
V_IN
R
V_OUT
MON_
EN_OUT_
MAX16046
MAX16048
where I_CP is the 6µA (typ) charge-pump source cur-
rent, C_GATE is the gate capacitance of the MOSFET,
and C_EXT is the capacitance connected from the gate
to ground. Power-down is not well controlled due to the
absence of the 100Ω pulldowns.
Figure 20. Connection for a p-Channel Series-Pass MOSFET
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