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■OPERATIONAL EXPLANATION (Continued)

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The XC6192 series has a function that limits rush current and a circuit that shuts down the output when an

output short-circuit is detected.

During the time until the VOUT pin voltage reaches VRUSH during the Turn-On sequence, only PM1 turns

ON, and therefore the voltage rises through the Pre-driver On Resistor (RONP: refer to the Electrical

Characteristics).

When the VOUT pin voltage reaches VRUSH or more, PM2 turns ON and rush current limiting is released.

The rush current at the instant when PM1 turns ON is calculated using the following equation.

In addition, during the time until the VOUT pin voltage reaches VRUSH by means of the rush current limiting

function, the load current while VOUT rises must be set to less than the value given by the equation below.

If the VOUT pin voltage drops below the Short Circuit Detect Voltage (VSHORT: refer to the Electrical

Characteristics) after the Turn-On sequence, a short-circuit is detected and PM1 and PM2 are latched in the

OFF state, causing VOUT to shut down. The relation between the output current (ISHORT) and VSHORT

when a short circuit occurs is given by the equation below.

The equation for the maximum output current is as follows.

Fig.9 Inrush current limit and output short circuit protection

Inrush Current Limit Voltage

SW Pin Voltage

PG Pin Voltage

Inrush Current

(CL Charge Current)

Short Circuit Detect Voltage

Output Current

Correct operation

Short Circuit 

operation

Inrush Current Limit 

operation

Short Current