2-1. Useful functions available with load switch ICs

Load switch ICs incorporate various functions that help ensure stable system operation.

Various functions

Integrated function


Overcurrent protection

This function limits the output current to protect a system in the event of excessive current flowing to a load switch IC, for example, when the load connected to the VOUT pin is short-circuited to GND.

Thermal shutdown

This function turns off a load switch IC when the heat it generates exceeds the heat dissipation capacity or when an increase in ambient temperature causes an excessive rise in junction temperature.

Inrush current limiting (slew rate control, soft start)

This function slowly raises the output voltage of a load switch IC at turn-on to ensure system stability.

Inrush current limiting is also known as slew rate control or soft start.

Auto discharge

When a load switch IC turns off, this function quickly discharges the smoothing capacitor connected to the VOUT pin to facilitate power supply sequencing.

Undervoltage lockout (UVLO)

When the input voltage of a load switch IC drops below a threshold, for example, because of noise or a decrease in battery voltage, this function turns off its output to prevent a system from becoming unstable.

Reverse-current blocking

This function prevents the load current from flowing in the reverse direction from the VOUT pin to the VIN pin when the VOUT voltage becomes higher than the VIN voltage. There are two types of reverse-current blocking: reverse-current blocking that blocks reverse current only when the internal MOS pass transistor is off and true reverse-current blocking that blocks reverse current regardless of whether it is on or off.

Chapter2 Convenient functions load switch ICs

2-2. Operation of overcurrent protection
2-3. Operation of thermal shutdown
2-4. Inrush current reducing
2-5. Auto discharge
2-6. Undervoltage lockout (UVLO)
2-7. Reverse-current protection

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