Hello,
When the output is shorted I assume the inverter switch current limit kicks in at around 1A and duty cycle is limited to its max specified value of 87.5%. With a Vin=5V, the device is dissipating 500 mW (500 m-ohm switch on-resistance) @ 87.5% duty cycle. The DRC package has a thermal resistance of 48.7C/W which raises the device to less than 24C above ambient.
Does this make sense or am I misinterpreting something?
Many thanks,
Tim Hoeppner
The IC protects against shorts by clamping the input current to the ILIM level in the datasheet. Assuming thermal protection does not shut down the IC, the IC will continue to switch but the duty cycle will be determined by the peak inductor current, i.e., the switch will turn on until its current reaches ILIM and then it turns off.
Thanks Jeff, that clears up things for me.