Voltage booster circuit of the charge-pump type with a bootstrapped oscillator
First Claim
1. A transistor switching control circuit comprising:
- a ring oscillator having an output that provides an oscillator signal at an oscillator frequency;
a phase splitter stage coupled to the ring oscillator, having an input that receives the oscillator signal and an output that provides a plurality of non-overlapping phase-split signals substantially at the oscillator frequency;
a non-bootstrapped output stage coupled to the phase splitter stage, having an input that receives the plurality of non-overlapping phase-split signals, and an output that provides a plurality of non-bootstrapped non-overlapping output signals that switch between a zero voltage and a supply voltage substantially at the oscillator frequency; and
a bootstrapped output stage coupled to the phase splitter stage, having an input that receives the plurality of non-overlapping phase-split signals, and an output that provides a plurality of bootstrapped non-overlapping output signals that switch between the zero voltage and a voltage of greater magnitude than the supply voltage substantially synchronously with the plurality of non-bootstrapped non-overlapping output signals.
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Accused Products
Abstract
The invention relates to charge-pump circuits used for the generation, in an integrated circuit, of an internal supply voltage Vpp which is considerably greater than the external supply voltage Vcc. In a charge pump configuration with capacitors and transistors, certain transistors must be driven by bootstrapped logic signals, i.e., having a logic level which is greater than Vcc in order to overcome the threshold voltage of the transistors. According to the invention, there is an oscillator followed by a phase splitter stage which is in turn followed by a bootstrap amplifier stage. The oscillator is a ring oscillator having a number of logic gates which is as small as possible, preferably only three. A satisfactory frequency stability of the charge pump is thus obtained and therefore its design is made easier and its adaptability to various electronic circuits is improved.
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Citations
20 Claims
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1. A transistor switching control circuit comprising:
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a ring oscillator having an output that provides an oscillator signal at an oscillator frequency; a phase splitter stage coupled to the ring oscillator, having an input that receives the oscillator signal and an output that provides a plurality of non-overlapping phase-split signals substantially at the oscillator frequency; a non-bootstrapped output stage coupled to the phase splitter stage, having an input that receives the plurality of non-overlapping phase-split signals, and an output that provides a plurality of non-bootstrapped non-overlapping output signals that switch between a zero voltage and a supply voltage substantially at the oscillator frequency; and a bootstrapped output stage coupled to the phase splitter stage, having an input that receives the plurality of non-overlapping phase-split signals, and an output that provides a plurality of bootstrapped non-overlapping output signals that switch between the zero voltage and a voltage of greater magnitude than the supply voltage substantially synchronously with the plurality of non-bootstrapped non-overlapping output signals. - View Dependent Claims (2, 3, 4, 5)
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6. A transistor switching control circuit for a charge pump, comprising:
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a ring oscillator having an output that provides an oscillator signal at an oscillator frequency; a phase splitter stage coupled to the ring oscillator, having an input that receives the oscillator signal and an output that provides a plurality of phase-split signals substantially at the oscillator frequency; a non-bootstrapped output stage coupled to the phase splitter stage, having an input that receives the plurality of phase-split signals, and an output that provides a plurality of non-bootstrapped output signals that switch between a zero voltage and a supply voltage substantially at the oscillator frequency; and a bootstrapped output stage coupled to the phase splitter stage, having an input that receives the plurality of phase-split signals, and an output that provides a plurality of bootstrapped output signals that switch between the zero voltage and a voltage of greater magnitude than the supply voltage substantially synchronously with the non-bootstrapped output signals. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13)
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14. An apparatus for controlling a charge pump circuit, the charge pump circuit creating an output voltage of greater magnitude than a supply voltage in response to signals received at an input of the charge pump circuit, the apparatus comprising:
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a control circuit, coupled to the charge pump circuit, the control circuit having an input that receives an oscillator signal at an oscillator frequency, a first output that provides a first plurality of phase-split signals, each of the first plurality of phase-split signals switching between a first voltage and a second voltage, and a second output that provides a second plurality of phase-split signals, each of the second plurality of phase-split signals switching between a first voltage and a third voltage that is different from the second voltage, the first and second plurality of phase-split signals providing control to the charge pump circuit when the first and second outputs are coupled to the input of the charge pump circuit; wherein the control includes; a phase splitter, having an input that receives the oscillator signal, a first output that provides a first plurality of intermediate signals and a second output that provides a second plurality of intermediate signals; a first output stage, having an input that receives the first plurality of intermediate signals and the second plurality of internal signals and an output that provides the first plurality of phase-split signals; and a second output stage, having an input that receives second plurality of intermediate signals and the second plurality of internal signals and an output that provides the second plurality of phase-split signals. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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Specification