OFF. With the inverting configuration, some level shifting is
required, because the ground pin of the regulator is no
longer at ground, but is now setting at the negative output
voltage level. Two different shutdown methods for inverting
regulators are shown in Figure 27 and 28.
Application Information (Continued)
INVERTING REGULATOR SHUTDOWN METHODS
To use the ON /OFF pin in a standard buck configuration is
@
simple, pull it below 1.3V ( 25˚C, referenced to ground) to
turn regulator ON, pull it above 1.3V to shut the regulator
01258342
FIGURE 27. Inverting Regulator Ground Referenced Shutdown
01258343
FIGURE 28. Inverting Regulator Ground Referenced Shutdown using Opto Device
27
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