Aspects of various embodiments of the present disclosure are directed to applications utilizing oscillator circuits. In certain embodiments, an apparatus includes an oscillator circuit having one or more capacitors. The oscillator circuit is configured to generate an oscillating signal by repeated charging and discharging of the capacitors. The apparatus also includes a control circuit connected to the oscillator. The control circuit is configured to set the oscillation frequency of the oscillator circuit as a non-linear function of an input control signal. For instance, in a more specific embodiment, the control circuit may be configured to set oscillation frequency of the oscillator circuit to a frequency scaled by a value raised to an exponent specified by the input control signal.

Aspects of various embodiments of the present disclosure are directed to applications utilizing oscillator circuits. In certain embodiments, an apparatus includes an oscillator circuit having one or more capacitors. The oscillator circuit is configured to generate an oscillating signal by repeated charging and discharging of the capacitors. The apparatus also includes a control circuit connected to the oscillator. The control circuit is configured to set the oscillation frequency of the oscillator circuit as a non-linear function of an input control signal. For instance, in a more specific embodiment, the control circuit may be configured to set oscillation frequency of the oscillator circuit to a frequency scaled by a value raised to an exponent specified by the input control signal.

A ramp generator includes an operational amplifier having an output to generate a ramp signal. An integration current source is coupled to a first input and a reference voltage is coupled to a second input of the operational amplifier. A feedback capacitor and a reset switch are coupled between the first input and the output of the operational amplifier. The reset switch is turned on to reset the ramp generator. A ramp event is configured to be generated in the ramp signal at the output of the operational amplifier in response to the reset switch being turned off. An assist current source is coupled between the output of the operational amplifier and ground. The assist current source is configured to conduct an assist current from the output of the operational amplifier to ground in response to the reset switch being turned off.

A ramp generator includes an operational amplifier having an output to generate a ramp signal. An integration current source is coupled to a first input and a reference voltage is coupled to a second input of the operational amplifier. A feedback capacitor and a reset switch are coupled between the first input and the output of the operational amplifier. The reset switch is turned on to reset the ramp generator. A ramp event is configured to be generated in the ramp signal at the output of the operational amplifier in response to the reset switch being turned off. An assist current source is coupled between the output of the operational amplifier and ground. The assist current source is configured to conduct an assist current from the output of the operational amplifier to ground in response to the reset switch being turned off.

Disclosed is an RC oscillator comprising: a bias circuit, generating first and second bias currents, and outputting a charging current proportional to a total bias current that is the sum of the first and second bias currents, wherein the ratio of the first bias current to the second bias current has a positive temperature coefficient; and an oscillation circuit, for periodically charging a capacitor using the charging current output by the bias circuit, and using a voltage across a resistor through which the second bias current or a current proportional thereto flows as a reference voltage to compare with a charging voltage on the capacitor, so as to obtain a periodically oscillating clock signal. Thus, the present disclosure can compensate the positive temperature coefficient of the subsequent delay and realize the RC oscillator with low temperature drift by making the charging time of the capacitor have a negative temperature coefficient.

Disclosed is an RC oscillator comprising: a bias circuit, generating first and second bias currents, and outputting a charging current proportional to a total bias current that is the sum of the first and second bias currents, wherein the ratio of the first bias current to the second bias current has a positive temperature coefficient; and an oscillation circuit, for periodically charging a capacitor using the charging current output by the bias circuit, and using a voltage across a resistor through which the second bias current or a current proportional thereto flows as a reference voltage to compare with a charging voltage on the capacitor, so as to obtain a periodically oscillating clock signal. Thus, the present disclosure can compensate the positive temperature coefficient of the subsequent delay and realize the RC oscillator with low temperature drift by making the charging time of the capacitor have a negative temperature coefficient.