Provided are an LDO, an MCU, a fingerprint module and a terminal device. The LDO includes: a reference voltage generating circuit and a source follower connected to the reference voltage generating circuit. The reference voltage generating circuit is used to generate a reference voltage that changes with temperature to offset a voltage change caused by a voltage between a first terminal and a second terminal of the source follower changing with time, so that an output voltage of the second terminal of the source follower does not change with temperature. The LDO omits an operational amplifier EA and a resistor divider feedback network in the prior art, which not only has a simple circuit structure, but also can achieve ultra-low power consumption.

Disclosed are a temperature compensation apparatus and method. The apparatus includes a reference signal generator that supplies at least one of a first current which is constant regardless of temperature variation and a second current which is proportional to temperature variation, a slope amplifier that determines a first output current having a second temperature coefficient which is a multiple of a first temperature coefficient of the second current, based on the first current and the second current, and a slope controller that determines a second output current having a third temperature coefficient, using a weighted average of the first current and the second current.

A semiconductor device includes; a resistor element connected to a first power supply node providing a first power supply voltage having a first magnitude, a PMOS transistor having a gate terminal connected to a second power supply node providing a second power supply voltage having a second magnitude less than the first magnitude, a source terminal connected to the resistor element, and a drain terminal providing a first current, and a first NMOS transistor configured as a diode-connected transistor, and connected between the drain terminal of the PMOS transistor and the second power supply node.

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.

Circuits, systems, and methods to automatically switch modes to provide constant reference voltages are discussed herein. For example, a bandgap reference system may include a first bandgap reference circuit configured to provide a first bandgap reference voltage, a low dropout regulator coupled to the first bandgap reference circuit, a temperature circuit coupled to the low dropout regulator, and a second bandgap reference circuit coupled to the low dropout regulator and the temperature circuit. The second bandgap reference circuit may be configured to configure one or more impedance elements based at least in part on a temperature signal and provide a second bandgap reference voltage based on one or more currents that pass through the one or more impedance elements.

An apparatus is described having a reference voltage circuit. The reference voltage circuit includes a diode to receive first and second currents having first and second respective current densities, where, the first and second current densities are different and determined by circuitry that precisely controls the respective amount of time the first and second currents flow into the diode. The reference voltage circuit also comprises circuitry to form a reference voltage by combining first and second voltages generated from respective voltages of the diode that result from the first and second currents flowing through the diode.

A semiconductor device includes: a voltage generation unit that generates a first voltage having a first temperature characteristic; a constant voltage generation unit that generates a constant voltage; and an adjustment unit that generates a second voltage having a second temperature characteristic and a third voltage having a third temperature characteristic using the first voltage and the constant voltage. The constant voltage generation unit generates the constant voltage independently of the adjustment unit. One of the second and third temperature characteristics is an opposite characteristic to the first temperature characteristic. The device can also include a control unit that selects one of the second and third voltages in response to a predetermined setting value.

A voltage generation circuit may include: a first transistor coupled to an internal supply voltage terminal, and configured as a diode-connected transistor; a second transistor coupled to the first transistor and configured as a diode-connected transistor; and a third transistor coupled between the second transistor and a ground voltage terminal, and configured to operate according to a first reference voltage generated based on an external supply voltage. The voltage generation circuit may limit a variation in level of a second reference voltage which is generated through a drain terminal of the second transistor as a threshold voltage of the second transistor rises according to a rise in level of the internal supply voltage.

The object of the present invention is to provide a current source which is capable of suppressing an increase in circuit size and by which a highly accurate constant current extremely stable to manufacturing variations or temperature fluctuations can be obtained. A current source circuit is provided with a nonvolatile storage element having a control gate region and a source region and operating as a field-effect transistor, and is configured to output a current in a state where a bias is applied between the control gate region and the source region.

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.