Embodiments of the disclosure are drawn to voltage reference circuits and methods of designing same. The voltage reference circuit may include a main stage and one or more auxiliary stages. The output of the main stage may be a reference voltage. The auxiliary stages may provide a feedback voltage that reduces a temperature dependence of the reference voltage. Each stage may include two or more transistors. The transistors may operate in a sub-threshold mode to provide the reference voltage.

A controllable temperature coefficient bias (CTCB) circuit is disclosed. The CTCB circuit can provide a bias to an amplifier. The CTCB circuit includes a variable with temperature (VWT) circuit having a reference circuit and a control circuit. The control circuit has a control output, a first current control element and a second current control element. Each current control element has a controllable resistance. One of the two current control elements may have a relatively high temperature coefficient and another a relatively low temperature coefficient. A controllable resistance of one of the current control elements increases when the controllable resistance of the other current control element decreases. However, the total resistance of the current control circuit remains constant with a constant temperature. The VWT circuit has an output with a temperature coefficient that is determined by the relative amount of current that flows through each current control element of the control circuit. A Current Digital to Analog Converter (IDAC) scales the output of the VWT and provides the scaled output to an amplifier bias input.

A tracking voltage generator, the latter including: a first transistor having a first leakage current and which is coupled with the flipped gate transistor so that a difference between a gate-source voltage (Vgs) of a flipped gate transistor and the first transistor is approximately equal to a bandgap voltage of a semiconductor material from which the tracking voltage generator is formed; an output node providing a tracking voltage which has a positive or negative temperature dependency based on the flipped gate transistor and the first transistor; and a second transistor connected to the output node and which has a second leakage current. A current reference includes: the tracking voltage generator; an amplifier to receive the tracking voltage and output an amplified signal; a control transistor to receive the amplified signal and conduct a reference current therethrough; and a control resistor connected in series with the control transistor.

A reference voltage generating circuit includes a bandgap reference (BGR) circuit configured to output an active reference voltage at a first node according to a sample signal; a first charging circuit configured to charge a first capacitor using the active reference voltage according to the sample signal; a second charging circuit configured to charge a second capacitor using the active reference voltage according to the sample signal; and a comparing circuit configured to compare a voltage difference between a charge voltage of the first capacitor and a charge voltage of the second capacitor with a threshold value, wherein the sample signal is a pulse signal generated using an output of the comparing circuit and the charge voltage of the first capacitor is provided as a low power reference voltage in a low power operation mode.

A bandgap reference circuit includes a circuit for high-order temperature curvature compensation; and a circuit for low output impedance and current drive capability, wherein an output voltage of the bandgap reference circuit can be independently adjusted to be either above or below a silicon bandgap voltage without impacting temperature curvature.

A circuit includes a first transistor that conducts a first current responsive to a DC bias voltage and an RF signal. A second transistor conducts a second current responsive to the DC bias voltage. The first current and the second current are mirrored through a pair of current mirrors coupled together through a low-pass filter to filter the envelope of the RF signal.

This invention aims at providing a temperature characteristic adjustment circuit capable of adjusting the temperature characteristic to various positive and negative temperature characteristics with an excessively small characteristic variation and capable of suppressing an increase in the chip area and the current consumption with a simple circuit configuration. A temperature characteristic adjustment circuit has a current source having a nonvolatile storage element having a control gate region and a source region and driven by the application of a bias between the control gate region and the source region and an output circuit not having a nonvolatile storage element, in which the temperature dependency of an output signal originating from the temperature dependency of the current amount of a current output from the current source is adjusted by the nonvolatile storage element.

A current reference comprising: a control resistor; a tracking voltage generator including: a first, flipped gate transistor having a first size; and a second transistor having a second size; wherein the tracking voltage generator is configured to output a tracking voltage having a first temperature dependency based on a ratio of the second size to the first size, the temperature dependency thereby being substantially equal to a second temperature dependency of the control resistor; and an amplifier circuit configured to receive the tracking voltage and maintain a voltage at a first terminal of the control resistor, the voltage being substantially equal to the tracking voltage; wherein the current reference thereby is configured to maintain a reference current through the control resistor at a constant value.

A reference voltage circuit includes a first output terminal from which a first reference voltage is supplied; a first MOS transistor of a depletion type, the first MOS transistor containing a drain connected to a power supply terminal, a gate connected to a ground terminal, and a source; a first voltage drop circuit including a first end connected to the source of the first MOS transistor and a second end connected to the first output terminal; and a second MOS transistor of a depletion type, the second MOS transistor containing a drain connected to the first output terminal, a gate connected to the ground terminal, and a source connected to the ground terminal.

A bandgap reference circuit includes a circuit for high-order temperature curvature compensation; and a circuit for low output impedance and current drive capability, wherein an output voltage of the bandgap reference circuit can be independently adjusted to be either above or below a silicon bandgap voltage without impacting temperature curvature.