LM217L/LM317L

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Figure 1 : Current Limit

Figure 2 : Minimum Operating Current

APPLICATION INFORMATION

The LM317L provides an internal reference voltage of 1.25V between the output and adjustments

terminals. This is used to set a constant current flow across an external resistor divider (see fig. 4), giving

all the regulator quiescent current is returned to the output terminal, imposing a minimum load current

condition. If the load is insufficient, the output voltage will rise.

Since the LM317L is a floating regulator and "sees" only the input-to-output differential voltage, supplies

of very high voltage with respect to ground can be regulated as long as the maximum input-to-output

differential is not exceeded. Furthermore, programmable regulator are easily obtainable and, by

connecting a fixed resistor between the adjustment and output, the device can be used as a precision

load to provide remote ground sensing.

Figure 3 : Basic Adjustable Regulator