Multiple frequency ring oscillator
First Claim
1. A multiple frequency oscillator, comprising:
- a plurality of inverter stages, each inverter stage including an input and an output, the input of each inverter stage coupled to the output of at least one other inverter stage, one of said inverter stage outputs supplying an oscillator output signal;
at least one of said inverter stages having an input for receiving a control signal, said control signal selectively having a first state or a second state, said at least one inverter stage responsive to said first state to cause said oscillator output signal to have a first frequency and responsive to said second state to cause said oscillator output signal to have a second frequency different from said first frequency, said at least one inverter stage including a plurality of parallel current paths, at least one of said current paths being non-conductive in response to said first state of said control signal and conductive in response to said second state of said control signal.
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Accused Products
Abstract
A multiple frequency oscillator responds to a control signal to selectively produce an output signal having a first frequency or a second frequency. The oscillator includes a plurality of inverter stages (481 -485) with the input of each inverter stage coupled to the output of another inverter stage. At least one of the inverter stages includes first and second transistors (50,51) having current paths connected in parallel, a third transistor (52) having a current path connected in series with the current paths of the first and second transistors (50, 51) between a first voltage source (Vdd) and the inverter stage output, and a fourth transistor (53) having a current path connected between the inverter stage output and a second voltage source (Vss). The control electrodes of the first, third, and fourth transistors (50, 52, 53) are connected to the input of the inverter stage. A control signal controls the conductivity of the second transistor (51) to select the frequency of output signal of the oscillator (44).
151 Citations
34 Claims
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1. A multiple frequency oscillator, comprising:
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a plurality of inverter stages, each inverter stage including an input and an output, the input of each inverter stage coupled to the output of at least one other inverter stage, one of said inverter stage outputs supplying an oscillator output signal; at least one of said inverter stages having an input for receiving a control signal, said control signal selectively having a first state or a second state, said at least one inverter stage responsive to said first state to cause said oscillator output signal to have a first frequency and responsive to said second state to cause said oscillator output signal to have a second frequency different from said first frequency, said at least one inverter stage including a plurality of parallel current paths, at least one of said current paths being non-conductive in response to said first state of said control signal and conductive in response to said second state of said control signal. - View Dependent Claims (2, 3)
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4. A multiple frequency oscillator for use on an integrated circuit selectively operable in a standby mode or an active mode, comprising:
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a plurality of inverter stages, each inverter stage including an input and an output, the input of each inverter stage coupled to the output of at least one other inverter stage, one of said inverter stage outputs supplying an oscillator output signal; at least one of said inverter stages having an input for receiving a control signal, said control signal having a first stage in the standby mode or a second state in the active mode, said at least one inverter stage responsive to said first state to cause said oscillator output signal to have a first frequency and responsive to said second state to cause said oscillator output signal to have a second frequency different from said first frequency, said at least one inverter stage including a plurality of transistors having parallel current paths, at least one of said transistors being non-conductive in response to said first state of said control signal and conductive in response to said second state of said control signal.
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5. A multiple frequency oscillator, comprising:
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a plurality of inverter stages, each inverter stage including an input and an output, the input of each inverter stage coupled to the output of another inverter stage, one of said inverter stage outputs supplying an oscillator output signal; at least one of said inverter stages including; first and second transistors having current paths connected in parallel; a third transistor having a current path connected in series with the current paths of said first and second transistors between a first voltage source and the output of said at least one inverter stage; a fourth transistor having a current path connected between said inverter stage output and a second voltage source; the input of said at least one inverter stage coupled to control electrodes of said fourth transistor and at least one of said first and third transistors; said second transistor having a control electrode for receiving a first control signal having a first state and a second state, said second transistor being non-conductive in response to said first control signal having said first state and conductive in response to said first control signal having said second state. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A voltage generator for supplying a bias voltage to a node in an integrated circuit, comprising:
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a multiple frequency oscillator for producing an output signal having a frequency selected in response to at least one control signal; and a charge pump responsive to said output signal for supplying said bias voltage to said node; said multiple frequency oscillator including; a plurality of inverter stages, each inverter stage including an input and an output, the input of each inverter stage coupled to the output of at least one other inverter stage, one of said inverter stage outputs supplying said output signal; at least one of said inverter stages having an input for receiving said control signal, said control signal selectively having a first state or a second state, said at least one inverter stage responsive to said first state to cause said output signal to have a first frequency and responsive to said second state to cause said output signal to have a second frequency different from said first frequency, said at least one inverter stage including a plurality of parallel current paths, at least one of said current paths being non-conductive in response to said first state of said control signal and conductive in response to said second state of said control signal. - View Dependent Claims (20, 21, 22)
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23. A multiple frequency oscillator, comprising:
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a plurality of inverter stages, each inverter stage including an input and an output, the input of each inverter stage coupled to the output of at least one other inverter stage, one of said inverter stage outputs supplying an oscillator output signal; at least one of said inverter stages having a frequency control circuit connected between a first voltage source and the output of said at least one inverter stage, said frequency control circuit receiving a first control signal selectively having a first state or a second state, said frequency control circuit having a first resistance in response to said first state to cause said oscillator output signal to have a first frequency and having a second resistance less than said first resistance in response to said second state to cause said oscillator output signal to have a second frequency greater than said first frequency; said at least one inverter stage including; a first transistor having a current path connected in parallel with said frequency control circuit; a second transistor having a current path connected in series with the current path of said first transistor between said first voltage source and the output of said at least one inverter stage; a third transistor having a current path connected between the output of said at least one inverter stage and a second voltage source; the input of said at least one inverter stage coupled to control electrodes of said third transistor and at least one of said first and second transistors. - View Dependent Claims (24, 25, 26, 27, 28)
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29. A multiple frequency oscillator, comprising:
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a plurality of inverter stages, each inverter stage including an input and an output, the input of each inverter stage coupled to the output of at least one other inverter stage, one of said inverter stage outputs supplying an oscillator output signal; at least one of said inverter stages receiving a first control signal, said first control signal selectively having a first state or a second state, said at least one inverter stage responsive to said first state to cause said oscillator output signal to have a first frequency and responsive to said second state to cause said oscillator output signal to have a second frequency different from said first frequency, the input of said at least one inverter stage remaining at a substantially constant capacitance irrespective of the state of said first control signal, said at least one inverter stage including a frequency control circuit connected between a first voltage source and the output of said at least one inverter stage, said frequency control circuit receiving said first control signal, said frequency control circuit having a first resistance in response to said first state to cause said oscillator output signal to have a first frequency and having a second resistance less than said first resistance in response to said second state to cause said oscillator output signal to have a second frequency greater than said first frequency; said at least one inverter stage including; a first transistor having a current path connected in parallel with said frequency control circuit; a second transistor having a current path connected in series with the current path of said first transistor between said first voltage source and the output of said at least one inverter stage; a third transistor having a current path connected between the output of said at least one inverter stage and a second voltage source; the input of said at least one inverter stage coupled to control electrodes of said third transistor and at least one of said first and second transistors. - View Dependent Claims (30, 31, 32, 33, 34)
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Specification