Existing proportional to absolute temperature (PTAT)/complementary-to-absolute-temperature (CTAT) reference voltage circuit requires a large components count and foot print, precise device matching for accuracy and unsatisfactory sensitivity error or variation to temperature and humidity. The present invention relates to a novel approach for such reference voltage circuit based on a self-biased complementary pair of n-type and p-type current field-effect transistors, which provides rail PTAT, rail CTAT and analog reference voltages.

A reference voltage generator circuit (100) is disclosed, comprising a first transistor (101) having a first channel type and a second transistor (102) having a second channel type. A current source (104) is connected to a source terminal of the first transistor (101). A drain terminal of the second transistor (102) is connected to a drain terminal of the first transistor (101). The reference voltage generator circuit (100) further comprises a third transistor (103) having the second channel type, wherein a drain terminal of the third transistor (103) is connected to a source terminal of the second transistor (102). A node between the source terminal of the second transistor (102) and the drain terminal of the third transistor (103) is connected to a gate terminal of the first transistor (101). A connection for a reference voltage (Vrc) is provided between the current source (104) and the source terminal of the first transistor (101).

A temperature sensor is disclosed. In one aspect, the temperature sensor provides a digital output having a precise degree/code step. For example, each step in the digital output code may correspond to one degree Celsius. In one aspect, a temperature sensor comprises a precision band-gap circuit and a sigma delta modulator (SDM) analog-to-digital convertor (ADC). A bandgap voltage and a PTAT voltage may be provided from the band-gap circuit as an input to the SDM ADC. The SDM ADC may produce an output based on the difference between the PTAT voltage and the bandgap voltage. The temperature sensor may also have logic that outputs a temperature code based on the output of the SDM ADC.

A voltage generation circuit having a temperature compensation function includes a first voltage generation circuit, a second voltage generation circuit, an output voltage control circuit, and a voltage selection circuit. The first voltage generation circuit is configured to generate a first voltage having a zero temperature coefficient, determined in response to a first control signal. The second voltage generation circuit is configured to generate a second voltage having a positive temperature coefficient, determined in response to a second control signal. The output voltage control circuit is configured to control an output of one of the first voltage and the second voltage in response to an operating mode. The voltage selection circuit is configured to select the first voltage or the second voltage in response to the output voltage control circuit.

A voltage generation circuit may include: a current providing block configured to provide, to an output node, a current corresponding to a voltage level of a set voltage, and a voltage level control block configured to adjust the resistance value thereof in response to a voltage control signal, wherein the voltage level control block is coupled between the output node and a ground terminal, and wherein the voltage level control block comprises a first current path unit and a second current path unit having different temperature characteristics.

A current reference circuit and a semiconductor IC including the current reference circuit, the current reference circuit including a proportional to absolute temperature (PTAT) current generator configured to generate, in an output branch, a first current proportional to a temperature; and a current subtractor configured to generate a reference current by subtracting a second current generated based on a current flowing in an internal branch of the PTAT current generator, from the first current flowing in the output branch. The second current is set to have a same temperature-based change characteristic as the first current and a level different from a level of the first current.

An apparatus for temperature sensing may include: a bias generator suitable for generating a complementary-to-absolute-temperature (CTAT) bias voltage; a regulator suitable for regulating a bias voltage by using CTAT bias voltage and outputting a regulated bias voltage; and a ring oscillator suitable for receiving the regulated bias voltage and generating an oscillation signal based on the regulated bias voltage.

A temperature dependent correction circuit includes a first supply source, a second supply source, a rectifying circuit, and a reference. The first supply source is configured to supply a first signal that varies with temperature along a first constant or continuously variable slope. The second supply source is configured to supply a second signal that varies with temperature along a second constant or continuously variable slope. The rectifying circuit is configured to receive the first and second signal, rectify the first signal to produce a first rectified signal, and add the first rectified signal to the second signal to produce a correction signal. The reference is configured to receive the correction signal.

A voltage reference circuit can operate in a large supply voltage range, including a low supply voltage, and can operate with high PSRR. The voltage reference circuit supplies a voltage reference with a near zero temperature coefficient (TC) across a wide-temperature range. The voltage reference circuit develops a first current with a positive temperature coefficient from a first transistor and a second current with a negative temperature coefficient from a second transistor. The control terminals of the two transistors are supplied by respective outputs of two error amplifiers. The two currents are combined to develop a voltage reference across a resistor. The voltage reference has a near zero temperature coefficient.

Apparatus for producing an electrical signal that is indicative of a temperature is disclosed, the apparatus comprising: a first thin-film transistor TFT comprising a first source, a first gate and a first drain, the first drain being configured to receive a reference current; and a second TFT comprising a second source, a second gate and a second drain, the first and second gates both being configured to receive the same gate voltage, wherein the first and second TFTs are configured such that a temperature dependence of the first TFT differs from a temperature dependence of the second TFT, such that an output current at the second TFT and the second drain is dependent on temperature. The temperature dependence of the output current can be controlled by selecting suitable design parameters for the first and second TFTs. A method of designing the apparatus to produce an output current with a target temperature dependence is also disclosed.