Methods and apparatus for generation of voltages
Methods of operating a voltage generation circuit, and apparatus configured to perform such methods, include applying a clock signal to an input of a voltage driver of a stage of the voltage generation circuit, connecting the voltage driver output to a first voltage node configured to receive a first voltage when the clock signal has a particular logic level and a voltage level of the voltage driver output is less than a threshold, connecting the voltage driver output to a second voltage node configured to receive a second voltage greater than the first voltage when the clock signal has the particular logic level and the voltage level of the voltage driver output is greater than the threshold, and connecting the voltage driver output to a third voltage node configured to receive a third voltage less than the first voltage when the clock signal has a different logic level.
1. A voltage generation system, comprising:
a first voltage generation circuit, the first voltage generation circuit comprising:
an input;
an output; and
a first plurality of stages between the input and the output of the first voltage generation circuit, wherein a stage of the first plurality of stages comprises:
a first voltage isolation device;
a first voltage driver having a first input connected to a first voltage node configured to receive a first voltage, a second input connected to a second voltage node configured to receive a second voltage less than the first voltage, and a third input configured to receive a first clock signal;
a first stage capacitance having a first electrode connected to an output of the first voltage driver and a second electrode connected to the first voltage isolation device;
wherein the first voltage driver is configured to connect its output to the first voltage node when the clock signal has a particular logic level; and
wherein the first voltage driver is further configured to connect its output to the second voltage node when the clock signal has a different logic level; and
a second voltage generation circuit, the second voltage generation circuit comprising:
an input connected to the output of the first voltage generation circuit;
an output; and
a second plurality of stages between the input and the output of the second voltage generation circuit, wherein a stage of the second plurality of stages comprises:
a second voltage isolation device;
a second voltage driver having a first input connected to a first voltage node configured to receive the first voltage, a second input connected to the output of the first voltage generation circuit, a third input connected to a third voltage node configured to receive the second voltage, and a fourth input configured to receive a second clock signal;
a second stage capacitance having a first electrode connected to an output of the second voltage driver and a second electrode connected to the second voltage isolation device;
wherein the second voltage driver is configured to connect its output to its first voltage node when the second clock signal has a particular logic level and a voltage level of its output is less than a threshold;
wherein the second voltage driver is further configured to connect its output to the output of the first voltage generation circuit when the second clock signal has its particular logic level and the voltage level of its output is greater than the threshold; and
wherein the second voltage driver is further configured to connect its output to its third voltage node when the second clock signal has a different logic level.
2. The voltage generation system of claim 1 , wherein the first voltage generation circuit and the second voltage generation circuit are each configured to generate an increasing voltage at their respective output.
3. The voltage generation system of claim 1 , wherein the first voltage generation circuit is configured to generate an increasing voltage at its respective output, and wherein the second voltage generation circuit is configured to generate a decreasing voltage at its output.