MAX15091 Datasheet, PDF (9/15 Pages) Maxim Integrated Products – Solution with Current Report Output

MAX15091/MAX15091A
2.7V to 18V, 9A, Integrated Hot-Swap
Solution with Current Report Output
Table 1. Output Enable Truth Table
POWER SUPPLY
V_CC
V_CC > V_UVLO
V_CC < V_UVLO
X
X
X = Don’t care.
V_{UV_TH} and V_{OV_TH} = 1.2V (typ).
PRECISION ANALOG INPUTS
UV
OV
V_UV > V_{UV_TH}
X
V_OV < V_{OV_TH}
X
V_UV < (V_{UV_TH} - V_{UV_HYS})
X
X
V_OV > V_{OV_TH}
OUT
On
Off
Off
Off
IN
R1
UV
MAX15091
MAX15091A
R2
1.2V
OV
R3
GND
CONTROL
LOGIC
Figure 1. Undervoltage/Overvoltage-Threshold Setting
Startup
Once the device output is enabled, the device provides
controlled application of power to the load. The voltage at
OUT begins to rise at approximately 10V/ms default until
the programmed circuit-breaker current level is reached,
while the devices actively limit the inrush current at the
circuit-breaker setting. An external capacitor connected to
the GATE pin allows the user to program the slew rate to
a value lower than the default. The inrush current can be
pro­grammed by selecting the appropriate value of R_CB.
During startup, a foldback current limit is active to protect
the internal MOSFET to operate within the SOA (Figure 2).
An internal 48ms timer starts counting when the devices
enter the startup phase. The devices complete the startup
phase and enter normal operation mode if the voltage
at OUT rises above the precharge threshold (0.9 x V_IN)
and (V_GATE - V_OUT) > 3V. An open-drain power-good
output (PG) goes high-impedance 16ms after the startup
successfully completes.
The thermal-protection circuit is always active and the
internal MOSFET immediately turned off when the
thermal-shutdown threshold condition is reached.
VariableSpeed/BiLevel Fault Protection
VariableSpeed/BiLevel fault protection incorporates com-
parators with different thresholds and response times to
monitor the load current (Figure 3). Protection is provided
in normal operation (after the startup period has expired)
by discharging the MOSFET gate in response to a fault
condition. During a fault condition, the MAX15091A enters
autoretry mode, while the MAX15091 latches off (see the
Autoretry and Latch-Off Fault Management section).
Enable Input (EN)
After a startup phase is successfully completed and the
power-good output asserted, the EN input has to be pulled
low (for at least 1ms) before the t_DLY delay elapses. If the
EN input is not pulled low before the t_DLY elapses, then
the devices turn off the internal MOSFET immediately
and a new cycle is required for entering power-up mode.
Connect a capacitor between CDLY and GND to set a 1s/
µF duration timeout delay. If this function in is not imple-
mented, connect EN to GND for proper operation.
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