An auto-tuned ramp generator and a method for generating a sawtooth signal are provided. In the method and apparatus, a sawtooth signal is compared to a first reference voltage and a second reference voltage. In response to determining that the sawtooth signal does not exceed the first reference voltage, the voltage level of the sawtooth signal is increased. In response to determining that the sawtooth signal exceeds the second reference voltage, the voltage level of the sawtooth signal is decreased. The voltage level the sawtooth signal is retained if the sawtooth signal remains between the first and second reference voltages.

A triangular wave generator includes a wave generator configured to generate a triangular wave according to a clock signal and a control signal. The triangular wave generator further includes a wave controller configured to adjust a value of the control signal in a correction mode. The control signal includes a first bias control signal, a second bias control signal, and a capacitance control signal.

A triangular wave generator includes a wave generator configured to generate a triangular wave according to a clock signal and a control signal. The triangular wave generator further includes a wave controller configured to adjust a value of the control signal in a correction mode. The control signal includes a first bias control signal, a second bias control signal, and a capacitance control signal.

An oscillation circuit includes resistors with tap points for high/low reference voltages. An RC network coupled in parallel with the resistors includes a first capacitor to vary a first voltage input and a second capacitor to generate a second voltage input. A first comparator alternately compares the voltage inputs with the low reference voltage to generate oscillation outputs. A PTAT current DAC supplies an injection current to a resistor of the series of resistors that variably modulates the reference voltages. A second comparator alternately compares the voltage inputs with the high reference voltage and controls generation of an adaptive bias current to first comparator near a switching threshold voltage range thereof. A chop switch matrix alternately flips voltage reference inputs to input terminals of first comparator. A multiplexer alternately inverts a polarity of the oscillation outputs in concert with alternately flipping the voltage reference inputs by the chop switch matrix.

Provided is a relaxation oscillator having an extremely small temperature deviation in oscillation frequency. A first current (I1) generated by a reference voltage source and a first resistor having a positive first-order temperature coefficient is supplied to a first variable capacitor (C1) for oscillation, and a second current (I2) generated by a reference voltage source and a second resistor having a negative first-order temperature coefficient is supplied to a second variable capacitor (C2) for oscillation. A product of a value of a ratio of a first current to a second current and a value of a ratio of a first-order temperature coefficient of the second resistor to a first-order temperature coefficient of the first resistor, and a value of a ratio of a capacitance of the first variable capacitor to a capacitance of the second variable capacitor have the same absolute value and opposite signs.

In a described example, an apparatus includes: a capacitor coupled to receive a current at a first terminal and having a second terminal coupled to ground; a first comparator coupled to a voltage at the first terminal of the capacitor and to a first reference voltage; a second comparator coupled to the voltage at the first terminal of the capacitor and to a second reference voltage that is different from the first reference voltage, and having an enable input coupled to the output of the first comparator; a discharge circuit coupled to the capacitor and enabled by the output of the second comparator; and a toggle circuit coupled to the output of the second comparator. Methods are disclosed.

In a described example, an apparatus includes: a capacitor coupled to receive a current at a first terminal and having a second terminal coupled to ground; a first comparator coupled to a voltage at the first terminal of the capacitor and to a first reference voltage; a second comparator coupled to the voltage at the first terminal of the capacitor and to a second reference voltage that is different from the first reference voltage, and having an enable input coupled to the output of the first comparator; a discharge circuit coupled to the capacitor and enabled by the output of the second comparator; and a toggle circuit coupled to the output of the second comparator. Methods are disclosed.

In one aspect, an apparatus includes an oscillator to generate a clock signal, where the oscillator includes: at least one resistor; at least one capacitor; and a circuit coupled to the at least one resistor and the at least one capacitor, the circuit to generate the clock signal. The apparatus further includes a voltage regulator coupled to the oscillator to provide a regulated voltage to the oscillator, and a bulk voltage generator coupled to the voltage regulator. The bulk voltage generator may provide first and second bulk voltages to the voltage regulator to provide temperature compensation to the oscillator.

In one aspect, an apparatus includes an oscillator to generate a clock signal, where the oscillator includes: at least one resistor; at least one capacitor; and a circuit coupled to the at least one resistor and the at least one capacitor, the circuit to generate the clock signal. The apparatus further includes a voltage regulator coupled to the oscillator to provide a regulated voltage to the oscillator, and a bulk voltage generator coupled to the voltage regulator. The bulk voltage generator may provide first and second bulk voltages to the voltage regulator to provide temperature compensation to the oscillator.

Disclosed is a differential relaxation oscillator using a differential structure that may stably maintain a differential voltage swing of capacitors despite an influence of an offset voltage and 1/f noise of a comparator, and also generate a dynamic current only at a point in time at which switching is performed, thereby minimizing power consumption.