Management of the EN pin to control the power consumption

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Management of the EN pin to control the power

consumption

The STCC2540 (and also the STCC50x1) device offers two states where all functionalities

are turned off:



EN = 0, CTLx ignored (for the STCC50x1 also ATTACH_EN = 0 condition applies)



EN = 1, CTLx = 000

Although from functional point of view these states are almost equivalent, they differ in

consumption. In the first case (EN = 0) the consumption of the STCCxxxx is the lowest

possible (up to 1

A) but there is one GPIO needed to control the EN pin, in the second

case (CTLx = 000) the consumption is 65

A but no more GPIO is necessary in most cases.

3.1

This is the simplest case. No more GPIO is necessary. To turn off the device, it is enough to

set the CTLx = 000. The drawback is the consumption in the OFF state which is 65

A.

The EN can also be connected to the POWER GOOD signal of the 5 V SMPS powering the

SMPS provides valid output voltage).

3.2

EN driven by GPIO

This case provides more flexibility (the device can be disabled in any case, e.g. if it reports

a fault condition) and lowest power consumption in the OFF state. However it needs one

more GPIO which complicates the implementation in many platforms.