TPS259250 Datasheet, PDF (14/35 Pages) Texas Instruments – Simple 5V/12V eFuse Protection Switches

TPS259250, TPS259251, TPS259260, TPS259261
SLVSCQ3A – AUGUST 2015 – REVISED AUGUST 2015
8 Detailed Description
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8.1 Overview
The TPS25925x/6x is an e-fuse with integrated power switch that is used to manage current/voltage/start-up
voltage ramp to a connected load. The device starts its operation by monitoring the VIN bus. When VIN exceeds
the undervoltage-lockout threshold (V_UVR), the device samples the EN/UVLO pin. A high level on this pin enables
the internal MOSFET. As VIN rises, the internal MOSFET of the device will start conducting and allow current to
flow from VIN to OUT. When EN/UVLO is held low (below V_ENF), internal MOSFET is turned off. User also has
the ability to modify the output voltage ramp time by connecting a capacitor between dV/dT pin and GND.
After a successful start-up sequence, the device now actively monitors its load current and input voltage,
ensuring that the adjustable overload current limit IOL is not exceeded and input voltage spikes are safely
clamped to VOVC level at the output. This keeps the output device safe from harmful voltage and current
transients. The device also has built-in thermal sensor. In the event device temperature (T_J) exceeds TSHDN,
typically 150°C, the thermal shutdown circuitry will shut down the internal MOSFET thereby disconnecting the
load from the supply. In TPS259250/60, the output will remain disconnected (MOSFET open) until power to
device is recycled or EN/UVLO is toggled (pulled low and then high). The TPS259251/61 device will remain off
and commences an auto-retry cycle of 145 ms after device temperature falls below T_SHDN – 10°C. This auto-retry
cycle will continue until the fault is cleared.
8.2 Functional Block Diagram
VIN
3,
4,
5
+
4.3V
4.08V
EN/
UVLO ²
+
1.4V
1.35V
UVLO
EN
Over
Voltage
Charge
Pump
Current _30m:
Sense
Thermal
GATE
SWEN _CONTROL
6V ^ShutDown _TSD
VIN
220nA
dV/dT
1
70pF
GND
EP
4.8x
SWEN
80:
ILIMIT
Fast Trip
Comp
+
1.6*ILIMIT
OUT
6,
7,
8
9 _N/C
6V
10uA
ILIM
+
10
8.3 Feature Description
8.3.1 GND
This is the most negative voltage in the circuit and is used as a reference for all voltage measurements unless
otherwise specified.
14
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Product Folder Links: TPS259250 TPS259251 TPS259260 TPS259261