A bandgap voltage circuit with a first circuit to generate an output voltage as a sum of a first voltage with an amplitude that is proportional to absolute temperature, and a first feedback voltage with an amplitude that is complementary to absolute temperature, a second circuit to generate a voltage having an amplitude that is complementary to absolute temperature, a scaling circuit to generate a second feedback voltage with an amplitude that is a fraction of the voltage of the control terminal, and a regulator circuit to regulate the first feedback voltage according to the second feedback voltage by controlling a first input current of the first circuit and a second input current of the second circuit.

A bandgap voltage circuit with a first circuit to generate an output voltage as a sum of a first voltage with an amplitude that is proportional to absolute temperature, and a first feedback voltage with an amplitude that is complementary to absolute temperature, a second circuit to generate a voltage having an amplitude that is complementary to absolute temperature, a scaling circuit to generate a second feedback voltage with an amplitude that is a fraction of the voltage of the control terminal, and a regulator circuit to regulate the first feedback voltage according to the second feedback voltage by controlling a first input current of the first circuit and a second input current of the second circuit.

Briefly, embodiments of claimed subject matter relate to comparison of a signal amplitude, such as a signal originating from a battery, for example, with a reference signal. A reference signal may be generated via body-biasing of one or more transistors, for example, which permit operation of the one or more transistors in a sub-threshold state, in which current through the one or more transistors comprises an exponential relationship to an applied voltage. Thus, at least in particular embodiments, detection of low battery voltage or battery overvoltage may be performed utilizing only a very small amount of electrical power.

An electronic device includes a module that delivers a positive temperature coefficient output voltage at an output terminal. A thermistor includes a first MOS transistor operating in weak inversion mode and having a negative temperature coefficient drain-source resistance and whose source is coupled to the output terminal. A current source coupled to the output terminal operates to impose the drain-source current of the first transistor.

Briefly, embodiments of claimed subject matter relate to comparison of a signal amplitude, such as a signal originating from a battery, for example, with a reference signal. A reference signal may be generated via body-biasing of one or more transistors, for example, which permit operation of the one or more transistors in a sub-threshold state, in which current through the one or more transistors comprises an exponential relationship to an applied voltage. Thus, at least in particular embodiments, detection of low battery voltage or battery overvoltage may be performed utilizing only a very small amount of electrical power

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).

In certain aspects, a bias generation circuit comprises a bias voltage generator. The bias voltage generator has a main NMOS transistor having a drain and a gate of the main NMOS transistor both coupled to a first terminal, a main resistor having a first main resistor terminal and a second main resistor terminal, wherein the first main resistor terminal couples to a source of the main NMOS transistor; and a main PMOS transistor having a source of the main PMOS transistor coupled to the second main resistor terminal and a drain and a gate of the main PMOS transistor both coupled to a second terminal, wherein the second terminal couples to a main ground. The bias generation circuit further comprises an array of sensors coupled to the first terminal and the second terminal.

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.

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 proportional-to-absolute-temperature current generating device includes a differential difference amplifier (DDA) that outputs a comparison signal based on a reference voltage, a first voltage, and a second voltage, a current source that generates a first current and a second current based on the comparison signal, a proportional-to-absolute-temperature voltage (VPTAT) generating unit that generates the first voltage based on the first current, and a complementary-to-absolute-temperature voltage (VCTAT) generating unit that generates the second voltage based on the second current. Each of the first current and the second current is a proportional-to-absolute-temperature current that increases in proportion to a temperature of the proportional-to-absolute-temperature current generating device.