Device description

PM8908

18/28

DocID027688 Rev 3

The maximum available load current, with the valley current limit technique, is equal to

Equation 2:

Equation 2

It is the sum of the valley current limit plus the half of the inductor current ripple.

During the overcurrent event the Vout drops until the UVP threshold, de-asserts the PGOOD

pin and then enters into the latch state.



Negative OCL

The negative OCL circuit operates when the converter is sinking the current from the output

During the overcurrent event the Vout goes up until the OVP threshold, de-asserts the

PGOOD pin and then enters into the latch state.

5.4.5

Overtemperature protection

It is recommended that the device never exceeds the maximum allowable junction

temperature. This temperature increase is mainly caused by the total power dissipated from

the integrated power MOSFETs.

To avoid any damage to the device when reaching high temperature, the PM8908

implements a thermal shutdown feature: when the junction temperature reaches 145 °C the

device turns off both MOSFETs. When the junction temperature drops to 135 °C, the device

restarts with a new soft-start sequence.

I

LOADmax

I

OCL

1

2

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I



+

=