Decreasing

Load

Resistance

0 A

0 V

Decreasing

Load

Resistance

0 A

0 V

Current Limit

with Peaking

Flat Current

Limit

11

TPS2001D

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SLVSE25A – JULY 2017 – REVISED OCTOBER 2017

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Feature Description (continued)

8.3.3 Internal Charge Pump

The device incorporates an internal charge pump and gate drive circuitry necessary to drive the N-channel

MOSFET. The charge pump supplies power to the gate driver circuit and provides the necessary voltage to pull

the gate of the MOSFET above the source. The driver incorporates circuitry that controls the rise and fall times of

the output voltage to limit large current and voltage surges on the input supply, and provides built-in soft-start

functionality. The MOSFET power switch blocks current from OUT to IN when turned off by the UVLO or

disabled.

8.3.4 Current Limit

Characteristics: TJ = TA = 25°C. When an overload condition is present, the device maintains a constant output

first overload condition occurs when either:

2. input voltage is present and the TPS2001D is enabled into a short circuit.

The output voltage is held near zero potential with respect to ground and the TPS2001D ramps the output

begins to thermal cycle.

The second condition is when an overload occurs while the device is enabled and fully turned on. The device

Characteristics: –40°C ≤ TJ ≤ 125°C) is applied. The response speed and shape varies with the overload level,

overload condition is removed or the device begins to thermal cycle.

The TPS2001D thermal cycles if an overload condition is present long enough to activate thermal limiting in any

temperature up. The device turns off when the junction temperature exceeds 135°C (minimum) while in current

limit. The device remains off until the junction temperature cools 20°C and then restarts.

There are two kinds of current limit profiles typically available in TI switch products that are similar to the

TPS2001D. Many older designs have an output I vs V characteristic similar to the plot labeled Current Limit with

not present noticeable peaking in the current limit, corresponding to the characteristic labeled Flat Current Limit

Figure 20. Current Limit Profiles