If the +5 and -5 rails were well regulated by ICs then a simple voltage divider string connected betwen them could give the +1 and -1 reference voltages.
If the +5 and -5 rails were well regulated by ICs then a simple voltage divider string connected betwen them could give the +1 and -1 reference voltages.
From the datasheet (LM117)
Besides replacing fixed regulators, the LM117 is useful in a wide variety of other applications. Since the regulator is "floating" and sees only the input-to-output differential voltage, supplies of several hundred volts can be regulated as long as the maximum input to output differential is not ex-ceeded, i.e., avoid short-circuiting the output.
From the datasheet (LM117)
Besides replacing fixed regulators, the LM117 is useful in a wide variety of other applications. Since the regulator is "floating" and sees only the input-to-output differential voltage, supplies of several hundred volts can be regulated as long as the maximum input to output differential is not ex-ceeded, i.e., avoid short-circuiting the output.
Well you could add a current limit circuit at the input to the regulators such as this, using transistors with sufficient voltage rating. You can use the same design for both the plus and minus sides. Just reverse the direction of the circuit (keeping the current flow direction the same).