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efox29
efox29
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I am unsure what the following statement on page 4 of this application note (Over Voltage Protection Circuit for Automotive Load Dump) means.

Resistor R4 provides a small amount of bias to Q2 in order to satisfy Q2 ’s drain leakage in the off state.

I assume R4 is to satisify Idss in the datasheet of 50uA but I am unsure how the value of R4 was even selected.

Does this mean that all mosfets must have their leakage currents requirements satisfied in order to work ? Why wasn't R5 + R6 not sufficient for this path ?

enter image description here

I am unsure what the following statement on page 4 of this application note (Over Voltage Protection Circuit for Automotive Load Dump) means.

Resistor R4 provides a small amount of bias to Q2 in order to satisfy Q2 ’s drain leakage in the off state.

I assume R4 is to satisify Idss in the datasheet of 50uA but I am unsure how the value was even selected.

Does this mean that all mosfets must have their leakage currents requirements satisfied in order to work ? Why wasn't R5 + R6 not sufficient for this path ?

enter image description here

I am unsure what the following statement on page 4 of this application note (Over Voltage Protection Circuit for Automotive Load Dump) means.

Resistor R4 provides a small amount of bias to Q2 in order to satisfy Q2 ’s drain leakage in the off state.

I assume R4 is to satisify Idss in the datasheet of 50uA but I am unsure how the value of R4 was even selected.

Does this mean that all mosfets must have their leakage currents requirements satisfied in order to work ? Why wasn't R5 + R6 not sufficient for this path ?

enter image description here

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efox29
efox29
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  • 106

What is the purpose of this bias resistor?

I am unsure what the following statement on page 4 of this application note (Over Voltage Protection Circuit for Automotive Load Dump) means.

Resistor R4 provides a small amount of bias to Q2 in order to satisfy Q2 ’s drain leakage in the off state.

I assume R4 is to satisify Idss in the datasheet of 50uA but I am unsure how the value was even selected.

Does this mean that all mosfets must have their leakage currents requirements satisfied in order to work ? Why wasn't R5 + R6 not sufficient for this path ?

enter image description here