Integrated switcher

Integrated Switcher 1C Solutions Versus Controller 1C Solutions... 

But unfortunately, once again, when dealing with fixed current limit (integrated) switchers, we will find that this nice-to-have transient headroom may be a luxury we just can t afford... 

We should also keep in mind that the above mentioned devices are bipolar-based integrated switchers. We can expect the situation to be better if we use integrated devices which use FET switches. On the other hand, if we are using controllers, then even with FET switches we should be cautious, because the switching speeds and corresponding delays are likely to be worse than with integrated switchers. It all boils down to our ability to set the current limit accurately and to enforce it fast enough. It is not a trivial proposition. 

But hold on a minute longer. Look at the published V-I curve (the black part of Figure A-3). This represents a typical integrated switcher device, rated for 1.5A. The device is therefore supposed to function up to 100°C at 1.5 A. But does the curve extend all the way Not at all The 100°C is mysteriously truncated No other information is available in the datasheet. The only way out for us as designers is to try to extrapolate the V-I curve. See gray part. 

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