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On-chip voltage controlled oscillator

  • US 5,604,466 A
  • Filed: 11/28/1994
  • Issued: 02/18/1997
  • Est. Priority Date: 12/08/1992
  • Status: Expired due to Fees
First Claim
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1. A circuit comprising:

  • a voltage regulator for rejecting low frequency noise from a regulated power supply, the voltage regulator including a voltage regulator output for providing a noise-attenuated regulated voltage; and

    an oscillator, the voltage regulator and the oscillator implemented on a common substrate, the oscillator coupled to the voltage regulator output,the voltage regulator further including attenuation means, which attenuation means includes a passive filter coupled to the regulated power supply for attenuating high frequency noise from the regulated power supply, and for supplying power from the power supply to the voltage regulator,wherein the passive filter includes a first resistor-capacitor pair for attenuating noise frequencies higher than a response ability of the voltage regulator, wherein the noise frequencies are higher than about 5 MHz, the passive filter further including a second resistor-capacitor pair for attenuating noise frequencies higher than about 800 MHz,wherein the attenuation means further includes means for maintaining an attenuation of at least about -30 dB for noise frequencies in a range from about DC to at least about 800 MHz,wherein the voltage regulator further includes a band gap circuit and regulator means for providing adequate current to maintain the regulated voltage while preventing noise from passing through the regulator means to the voltage regulator output, the regulator means including a Darlington pair coupled to the voltage regulator output, and a control terminal of the Darlington pair coupled to the band gap circuit for receiving variable current, the band gap circuit coupled to the voltage regulator output and controlling the variable current in response to changes in the regulated voltage,wherein the oscillator comprises a multivibrator which includes a control voltage input, and capacitors connected in parallel, wherein a top plate of one of the capacitors is connected to a bottom plate of another one of the capacitors for providing a symmetric capacitance, and further wherein the control voltage input comprises a first transistor for receiving a control voltage signal, the first transistor coupled to the regulated power supply and to one end of a resistor, another end of the resistor coupled to both a collector and a base of a second transistor, the second transistor coupled to a plurality of transistors to form a multiple output current mirror, the multiple output current mirror coupled to the capacitors connected in parallel.

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