Overcurrent protection function (OCP)

The overcurrent protection function prevents damage to the IC and load by suppressing power consumption in the event of an error. If the output current exceeds the limit current (ILIM) due to a load error or short circuit, the output voltage and output current also decrease, thereby limiting the power consumed by the ICs and the load.

This overcurrent protection has the advantage of being adjustable with an external resistor.

The resistor surrounded by a red frame in the circuit diagram shown at left is an external resistor RILIM.
With this external resistor, the overcurrent limit can be set to 0.5A~5A for TCKE8 Series.

This overcurrent limit and external resistor RILIM are shown in the diagram at right and the equation below it.
As shown in this graph, the overcurrent limit is determined according to the resistance value.

It has the advantage of improving design flexibility because the overcurrent limit can be set arbitrarily simply by changing one external resistor.
(Be sure to check the resistance value with the actual machine when selecting the resistance value.)

Even if you think that poly fuses and chip fuses can protect the circuits, there is a possibility that the circuits cannot actually be protected.

This diagram compares the overcurrent protection operation among between the eFuse IC and Poly fuse and chip fuse.
(For comparative purposes, eFuse IC overcurrent setting, poly fuse, and chip fuse ratings are unified around 3A.)

When the overcurrent of 5A was applied,

•  eFuse IC turned off  the current and the output voltage in only 1μs-2μs
•  the poly-fuse and chip-fuse could not turned off the current even if the overcurrent of 5A was applied , and the output voltage also remained on.

When an overcurrent of 10A was applied,

•  eFuse IC turned off at only 1μs-2μs as in the case of 5A.
•  the polyfuse turned off 2.6 seconds, the chip fuse did 3.5μs,
  however, the chip fuse was bloken, and needed to replace it.

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