Method and circuit for regulating the output voltage from a charge pump circuit, and memory device using same

A method of controlling a charge pump circuit to generate a pumped voltage, the charge pump circuit including a plurality of voltage-boosting stages connected in series, the method comprising:

• coupling the final voltage-boosting stage to a pumped output node;
• controlling the voltage-boosting stages to generate a pumped voltage on the pumped output node;
• monitoring a value of the pumped voltage;
• in response to the monitored value of the pumped voltage being greater than a threshold value,
• controlling the voltage-boosting stages to stop generating the pumped voltage, and
• isolating the final voltage-boosting stage from the pumped output node.

A method of sequentially pumping charge from one node to an adjacent node in a series of connected nodes to generate a pumped voltage on an output node corresponding to a final node in the series, the method comprising:

• pumping charge from each odd node in the series to the next adjacent even node;
• pumping charge from each even node in the series to the next adjacent odd node;
• pumping charge from the even or odd node adjacent the output node to the output node to develop the pumped voltage on the output node;
• monitoring a value of the pumped voltage;
• when the monitored value of the pumped voltage has a magnitude greater than a threshold value, terminating the pumping of charge from the even or odd node adjacent the output node to the output node and terminating the pumping of charge from each odd node in the series to the next adjacent even node and the pumping of charge from each even node in the series to the next adjacent odd node;
• and
• when the monitored value of the pumped voltage has a magnitude less than or equal to the threshold value, pumping charge from the even or odd node adjacent the output node to the output node and pumping charge from each odd node in the series to the next adjacent even node, and pumping charge from each even node in the series to the next adjacent odd node.

A charge pump circuit for generating a boosted voltage, comprising:

• a plurality of voltage-boosting stages coupled in series and each voltage-boosting stage having a clock terminal adapted to receive a clock signal and generating a boosted voltage responsive to the clock signal;
• an isolation circuit coupled between a final voltage-boosting stage in the series and an output node on which the boosted voltage is generated, the isolation circuit including a control terminal adapted to receive a disable signal and being operable to apply an interim boosted voltage generated by the final voltage-boosting stage on the output node as the boosted voltage in response to the disable signal being inactive, and operable to isolate the final voltage-boosting stage from the output node responsive to the disable signal being active;
• and
• a control circuit coupled to the control terminal, the control circuit generating the active disable signal responsive to the boosted voltage on the output node being greater than a desired value.