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US 2003/0197535 A1Published application
Method and apparatus for change pump circuit
AssigneeWinbond Electronics Corp.
InventorYung-Chow Peng
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AssigneeWinbond Electronics Corp.
InventorYung-Chow Peng
Estimating the term…
Charge-pumps consistent with this invention comprise a first transistor for sinking a current from an output node; a second transistor coupled between the first transistor and a ground node, wherein the second transistor interrupts the sinking current when the second transistor is turned off; and a current source to provide a turn-off current to a common node between the first transistor and the second transistor when the second transistor interrupts the sinking current. Charge-pump circuits consistent with this invention comprise a first transistor for sinking a current from an output node; a second transistor coupled between the first transistor and a ground node, wherein the second transistor interrupts the sinking current when the second transistor is turned off; and a clamping circuit to clamp a common node between the first transistor and the second transistor below a clamping voltage.
A charge-pump circuit comprising:
A charge-pump circuit comprising:
A method for operating a charge-pump circuit, wherein the charge-pump circuit comprises a first transistor for sinking a current from an output node and a second transistor coupled between the first transistor and a ground node, wherein the second transistor interrupts the sinking current when the second transistor is turned off, wherein the method comprises:
A method for operating a charge-pump circuit having a first transistor for sinking a current from an output node and a second transistor coupled between the first transistor and a ground node, wherein the second transistor interrupts the sinking current when the second transistor is turned off, wherein the method comprises:
A charge-pump circuit comprising:
A charge-pump circuit comprising:
A method for operating a charge-pump circuit, wherein the charge-pump circuit comprises a first transistor for driving a current from an output node and a second transistor coupled between the first transistor and a ground node, wherein the second transistor interrupts the driving current when the second transistor is turned off, wherein the method comprises:
A method for operating a charge-pump circuit having a first transistor for driving a current from an output node and a second transistor coupled between the first transistor and a ground node, wherein the second transistor interrupts the driving current when the second transistor is turned off, wherein the method comprises:
An apparatus for operating a charge-pump circuit, wherein the charge-pump circuit comprises a first transistor for sinking a current from an output node and a second transistor coupled between the first transistor and a ground node, wherein the second transistor interrupts the sinking current when the second transistor is turned off, wherein the apparatus comprises:
An apparatus for operating a charge-pump circuit having a first transistor for sinking a current from an output node and a second transistor coupled between the first transistor and a ground node, wherein the second transistor interrupts the sinking current when the second transistor is turned off, wherein the apparatus comprises:
A phase-locked loop having a phase detector, a low pass filter, a voltage controlled oscillator, and a charge-pump circuit, wherein the charge pump circuit comprises:
A phase-locked loop having a phase detector, a low pass filter, a voltage controlled oscillator, and a charge-pump circuit, wherein the charge pump circuit comprises:
Dependencies are inferred from the claim text.
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From the US filing history. Foreign family members aren’t listed.
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The up-down pulses controlling source and sink current generators, e.g. a charge pump: details of the current generators
Indirect frequency synthesis, i.e. generating a desired one of a number of predetermined frequencies using a frequency- or phase-locked loop:…
Automatic control, starting, synchronisation or stabilisation of generators of electronic oscillations or
Term end not estimated
1. Field of the Invention
This invention relates to charge pump circuits, such as charge pump circuits that may be used, for example, in phase-locked loops (PLLs).
2. Background of the Invention
FIG. 1 is a block diagram of a conventional PLL;
FIG. 2 is a circuit diagram of a sinking path circuit of a conventional charge pump that may be used in the PLL of FIG. 1;
FIG. 3 is a circuit diagram of a sinking path of a charge pump circuit consistent with this invention;
Reference is made below in detail to the present exemplary embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference characters or numbers are used throughout the drawings to refer to the same or like parts.
FIG. 3 is a circuit diagram of a sinking path 300 of a charge pump circuit consistent with this invention. The embodiment shown in FIG. 3 comprises four MOS transistors mn7, mn8, mn9, and mnr. Transistor mn7 acts as a current sinking device and comprises a gate connected to a voltage bias signal vb1; a drain that sinks a current I(mn7) from an output node 304; and a source connected to the drain of transistor mn8 at a common node 302. Voltage vb1 is a bias voltage that controls the magnitude of sinking current I(mn7) to output node 304. A current mirror circuit similar to that discussed with respect to charge-pump circuit 200 of FIG. 2 may supply bias voltage vb1.
Transistor mn8 acts as a current control device and comprises a source connected to ground; a drain connected to the source of transistor mn7 at common node 302; and a gate connected to an input signal a2˜. When the voltage of signal a2˜ is sufficiently high, transistor mn8 turns on and couples the source of transistor mn7 to ground and current I(mn7) passes through transistors mn7 and mn8. Alternatively, when the voltage of signal a2˜ is sufficiently low, transistor mn8 turns off and the source of transistor mn7 does not have a substantially conductive path to ground. Thus, when mn8 turns off, transistor mn7 subsequently turns off as well. When transistor mn8 is off, substantially no current passes through transistor mn7 or transistor mn8, i.e., I(mn7) is substantially zero. Current I(mn7) may form part of output current IO.