MAX15090_13 Datasheet, PDF (9/15 Pages) Maxim Integrated Products – 2.7V to 18V, 12A, Hot-Swap Solution with Current Report Output

MAX15090/MAX15090A
2.7V to 18V, 12A, 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} = 1.23V (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
MAX15090
MAX15090A
R2
1.23V
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 50ms timer starts counting when the devices
enter the startup phase. The devices complete the start-
up 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 MAX15090A enters
autoretry mode, while the MAX15090 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/FF duration timeout delay. If this
function in is not implemented, connect EN to GND for
proper operation.
Maxim Integrated
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