Datasheet

TPS2480

TPS2481

SLUS939B –APRIL 2010–REVISED DECEMBER 2010

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APPLICATION INFORMATION

Basic Operation

The TPS2480/81 provides all the features needed for a positive hotswap controller.

These features include:

1. Under-voltage lockout;

2. Adjustable (system-level) enable;

3. Turn-on inrush limit;

4. High-side gate drive for an external N-channel MOSFET;

5. MOSFET protection (power limit and current limit);

6. Adjustable overload timeout (also called an electronic circuit breaker);

7. Charge-complete indicator for downstream converter sequencing; and

8. Optional automatic restart mode.

The TPS2480/81 features superior power-limiting, MOSFET protection that allows independent control of current

limit (to set maximum full-load current), power limit and overload time (to keep FET in its SOA), and overload

time (to control case temperature rise). The typical application circuit, and oscilloscope plots of Figure 12 and

Figure 16 demonstrate many of the functions described above.

Board Plug-In (Figure 12)

Only the bypass capacitor charge current and small bias currents are evident when a board is first plugged in.

The TPS2480/81 is held inactive, and GATE, PROG, TIMER, and PG are held low for less than 1 ms while

internal voltages stabilize, then GATE, PROG, TIMER, and PG are released and the part begins sourcing current

to the GATE pin and the external FET begins to turn on while the voltage across it, V

(SENSE-OUT)

, and current

through it, V

(VCC-SENSE)

, are monitored. Current initially rises to the value which satisfies the power limit engine

LIM

÷V

VCC

) since the output capacitor was discharged.

Product Folder Link(s): TPS2480 TPS2481