Thermal Shutdown feature in an IC

[FreshmanNewbie]

I'd like to understand more about Thermal shutdown in an IC.

I have read that, if the IC junction temperature exceeds beyond a certain limit, the IC shuts down itself which is known as thermal shutdown.

But once the IC is shutdown, how does it recover back and start to work normally?

1. Do we need to do a power cycle to make the IC work ?
2. Or once the junction temp reduces to a certain value, the IC will start working again?

How does it work back again?

I'm using this - IC. Not much information is given on this regarding the IC's thermal shutdown. Just it is mentioned that this IC has this feature.

So what conditions should happen for this IC (also in general) to go into thermal shutdown?

 

[KlausST]

Hi,

thermal shutdown is an individual feature.
Thus you need to read the individual datasheet.

In the current datasheet there is indeed not much information. The datasheet link to the LDOBk_ds.pdf does not work for me.

Klaus

 

[FvM]

So what conditions should happen for this IC (also in general) to go into thermal shutdown?

The condition is clearly stated in the datasheet:

Exceeding the maximum allowable power dissipation will result in excessive die temperature, and the regulator will go into thermal shutdown.

 

[danadakk]

The control loop senses T, and when T drops below internal set value, the
amp stages, typically bias, are turned on. Take my post with a grain of salt in
that the precise behavior of the control loop best commented on by an
actual IC designer.

Some info here in this patent application -

Thermal shutdown circuit - National Semiconductor Corporation

A circuit is arranged to provide a thermal shutdown signal in response to an overtemperature condition. The thermal shutdown circuit is typically implemented in the same die as the circuitry that is t

www.freepatentsonline.com

Regards, Dana.

 

[kamdesign]

LDOs will shutdown when Tj goes above 125 C, and restart only when Tj falls below approx. 100 C regardless of the application of power. Normally a short circuit at the LDO output will cause the device to overheat, and power down is required to allow the device to cool down. Repeated thermal shutdown events will stress the part and reduce reliability.

 

[dick_freebird]

You can have real time or you can have latched overtemp
protection (see similarly in overcurrent / short circuit
protection). Depends on what you want the fault response
recovery to be. Systems that operate away from "intervention"
will probably want a real time protection that resets when
conditions are back in range. Consumer systems that
have significant tort exposure, probably are best off with a
reset that requires power cycle, to put the responsibility
squarely on Somebody Else. Easier to pass a UL flammability
test if the "heater" quits after the first trip, than "motorboating"
until the next domino does its thing.