Trimmable oscillator

A trimmable oscillator circuit, comprising:

• a comparator circuit operable to compare an output voltage of the oscillator circuit to a reference voltage and output a control signal in response thereto;
• an output capacitor, wherein a voltage at a node of the capacitor comprises the output voltage of the oscillator circuit;
• and
• a selectively trimmable charge/discharge circuit coupled between the comparator circuit and the output capacitor, and operable to charge or discharge the output capacitor based on the control signal, and wherein a rate of charge or discharge is dictated by one or more user selectable control signals, thereby dictating a frequency of the output voltage,
• wherein the selectively trimmable charge/discharge circuit comprises a selectively trimmable charge circuit operable to exhibit a resistance having a value which is a function of the one or more user selectable control signals, and forming an RC network in which a rate of charge of the output capacitor is a function of the resistance value, thereby influencing a frequency of the output signal at the output capacitor node, and
• wherein the selectively trimmable charge circuit comprises:
• a plurality of differing value resistances which are selectively coupled between a circuit supply potential and the node of the output capacitor through a base charge resistance;
• and
• a charge control circuit enabled by a state of the control signal, and operable to couple one of the plurality differing value resistances to the base charge resistance based on the one or more user selectable control signals, thereby providing a unique charging resistance value which is a function of the one or more user selectable control signals.

A trimmable oscillator circuit, comprising:

• a comparator circuit operable to compare an output voltage of the oscillator circuit to a reference voltage and output a control signal in response thereto;
• an output capacitor, wherein a voltage at a node of the capacitor comprises the output voltage of the oscillator circuit;
• and
• a selectively trimmable charge/discharge circuit coupled between the comparator circuit and the output capacitor, and operable to charge or discharge the output capacitor based on the control signal, and wherein a rate of charge or discharge is dictated by one or more user selectable control signals, thereby dictating a frequency of the output voltage,
• wherein the selectively trimmable charge/discharge circuit comprises a selectively trimmable discharge circuit operable to exhibit a resistance having a value which is a function of the one or more user selectable control signals, and forming an RC network in which a rate of discharge of the output capacitor is a function of the resistance value, thereby influencing a frequency of the output signal at the output capacitor node.

A trimmable oscillator circuit, comprising:

• a comparator circuit operable to compare an output voltage of the oscillator circuit to a reference voltage and output a control signal in response thereto;
• an output capacitor, wherein a voltage at a node of the capacitor comprises the output voltage of the oscillator circuit;
• a selectively trimmable charge/discharge circuit coupled between the comparator circuit and the output capacitor, and operable to charge or discharge the output capacitor based on the control signal, and wherein a rate of charge or discharge is dictated by one or more user selectable control signals, thereby dictating a frequency of the output voltage, and
• a reference voltage generation circuit coupled to the comparator circuit, and operable to provide a reference voltage having a first value when the control signal comprises a first state, and a second value when the control signal comprises a second state.

A low voltage trimmable RC oscillator circuit, comprising:

• a comparator circuit operable to generate a control signal based on a comparison between an oscillator output voltage and a reference voltage;
• a charge/discharge circuit operable to selectively serially couple a charge resistance or a discharge resistance to a capacitor to form an RC network, wherein a rate of charge or discharge of the capacitor is a function of a magnitude of the charge resistance or the discharge resistance, respectively;
• and
• a control circuit operable to dictate a charge mode or a discharge mode of the charge/discharge circuit based on the control signal and further operable to adjust the magnitude of the charge resistance or the discharge resistance, respectively, based on one or more oscillation frequency control signals,
• wherein the control circuit comprises eight logic gates each having three inputs coupled to three oscillation frequency control signals, respectively, and wherein one of the eight logic gate outputs a resistance control signal based on a state of the oscillation frequency control signals, thereby enabling a coupling of a resistance value in a charge path or a discharge path, respectively.