In a 3D memory with vertical local bit lines, each local bit line is switchably connected to a node on a global bit line having first and second ends, the local bit line voltage is maintained at a predetermined reference level in spite of being driven by a bit line driver from a first end of the global bit line that constitutes variable circuit path length and circuit serial resistance. This is accomplished by a feedback voltage regulator comprising a voltage clamp at the first end of the global bit line controlled by a bit line voltage comparator at the second end of the global bit line. The comparator compares the bit line voltage sensed from the second end with the predetermined reference level and outputs a control voltage to control the voltage clamp In this way the voltage at the local bit line is regulated at the reference voltage.