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Product features

STPM801 is a controller which operates with external back-to-back connected N-channel power MOSFETs,

realizing a connection between the input voltage supply line, connected to VB, and the output supply line OUT.

STPM801 makes, therefore, available, on OUT, a voltage supply protected against high voltage transients and

high load currents. The product can be used either for 12 V or 24 V supply rails.

The two N-channel transistors driven by the device are, respectively, the hot swap and the oring MOSFETs. The

first is used as a normal power switch; the soft Start function helps to limit the inrush current during the device

power-up. The oring MOSFET is mainly used as ideal diode, but it helps also blocking the current conduction in

case of reverse battery detection.

External capacitor connected to HGATE is used to define soft start time, together with HGATE current provided by

the device.

The device regulates the forward voltage drop across the oring MOSFET, used as ideal diode (by modulating

DGATE voltage), in order to ensure smooth current transfer from one supply to the other, without oscillations. The

ideal diode turns on quickly to reduce load voltage drop during supply switch over. Reverse current transients are

minimized by means of the reverse battery detection.

Pre-driver acting on DGATE performs fast turn on/turn off, in order to withstand with fast transients pulses of

ISO 16750 standard. For driving external MOSFETS with proper timings, a charge pump with external flying and

tank capacitors is realized.

A current sense amplifier translates the voltage drop across a shunt resistor to an internal overcurrent flag.

Undervoltage (UV) and overvoltage (OV) on diagnosis on VB are present. Detection thresholds are defined by

means of an external voltage divider.

Short to GND (STG) detection on VOUT is present.

VDS comparators are present on both soft start and oring MOSFETs.

ENOUT and FLT are open drain outputs. ENOUT is activated at the startup if VB-VOUT voltage drop is lower than

VFULL_ON. FLT is asserted whenever an internal fault is detected.

A standby mode is also available, with device operating at reduced functionality, but allowing a reduction on

power dissipation.

STPM801

Product features

DS13990 - Rev 2

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