Stage based frequency optimization for area reduction of charge pumps
AssigneeSanDisk Technologies LLC
InventorsV. S. N. K. Chaitanya G, Ankit Rehani, Pradeep Kumar Anantula
Life of this patent
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Abstract
A stage-based frequency optimization for a charge pump achieves a higher area efficiency by operating different stages of the charge pump at their optimized frequency simultaneously, instead of single common frequency, to obtain greater output strength. A first set of stages uses triple well devices as transfer switches and operates at a first, higher frequency. The first stages supply a second set of stages using high voltage devices as transfer switches and operates at a second, lower frequency. The two set of stages are connected through a frequency transition circuit.
Claims20
A non-volatile memory device, comprising:
- a control circuit configured to connect to an array of non-volatile memory cells, the control circuit comprising a charge pump circuit including:
- a first plurality of charge pump stages configured to receive a supply voltage level and to generate an intermediate voltage level from the supply voltage level;
- a second plurality of charge pump stages configured to receive the intermediate voltage level and to generate an output voltage level from the intermediate voltage level;
- and
- a frequency transition circuit connected to receive the intermediate voltage from the first plurality of charge pump stages and supply the intermediate voltage to the second plurality of charge pump stages and configured to receive charge from the first plurality of charge pump stages and to supply the received charge to the second plurality of charge pump stages,
- the control circuit configured to:
- operate the first plurality of charge pump stages at a first frequency to generate the intermediate voltage level;
- operate the second plurality of charge pump stages at a second frequency to generate the output voltage level;
- operate the frequency transition circuit to receive charge from the first plurality of charge pump stages at the first frequency and supply the received charge to the second plurality of charge pump stages at the second frequency;
- and
- apply the generated output voltage level to one or more of the memory cells of the array.
A method, comprising:
- receiving, at a first plurality of charge pump stages, an input voltage level;
- operating the first plurality of charge pump stages at a first frequency to generate an intermediate voltage level from the input voltage level;
- receiving the intermediate voltage at a frequency transition circuit, including receiving charge from the first plurality of charge pump stages at the first frequency;
- supplying the intermediate voltage from the frequency transition circuit to a second plurality of charge pump stages, including supplying the received charge to the second plurality of charge pump stages at a second frequency;
- and
- operating the second plurality of charge pump stages at the second frequency to generate an output voltage level from the intermediate voltage level as received from the frequency transition circuit.
A charge pump system, comprising:
- a first plurality of charge pump stages configured to operate at a first frequency to generate an intermediate voltage level from an input voltage level;
- a second plurality of charge pump stages configured to operate at a second frequency to generate an output voltage level from the intermediate voltage level;
- and
- a frequency transition circuit connected to receive the intermediate voltage from the first plurality of charge pump stages and supply the intermediate voltage to the second plurality of charge pump stages and configured to receive charge from the first plurality of charge pump stages at the first frequency and supply the received charge to the second plurality of charge pump stages at the second frequency.
Dependencies are inferred from the claim text.