A voltage regulation circuit includes a node, a voltage regulator, a plurality of load units and a voltage feedback circuit. The node has a node voltage. The voltage regulator is electrically connected to the node. The load units are electrically connected to the voltage regulator via the node. The load units are driven by the node voltage and have at least one load state. The voltage feedback circuit is electrically connected between the voltage regulator and the node. The voltage feedback circuit includes a switch and receives the node voltage and a control signal. The control signal includes the at least one load state. The voltage feedback circuit controls the switch according to the at least one load state of the control signal to output a feedback voltage. The voltage regulator adjusts the node voltage according to the feedback voltage.

A voltage regulation circuit includes a node, a voltage regulator, a plurality of load units and a voltage feedback circuit. The node has a node voltage. The voltage regulator is electrically connected to the node. The load units are electrically connected to the voltage regulator via the node. The load units are driven by the node voltage and have at least one load state. The voltage feedback circuit is electrically connected between the voltage regulator and the node. The voltage feedback circuit includes a switch and receives the node voltage and a control signal. The control signal includes the at least one load state. The voltage feedback circuit controls the switch according to the at least one load state of the control signal to output a feedback voltage. The voltage regulator adjusts the node voltage according to the feedback voltage.

The present disclosure relates to an apparatus for determining and/or monitoring at least one process variable of a medium in a containment, comprising a sensor unit and an electronics unit, wherein the electronics unit includes a transceiver unit and a transceiver protecting unit for limiting an input voltage of the transceiver unit to a first transceiver voltage value. According to the present disclosure, the transceiver protecting unit includes a first limiting unit and a transistor unit, the transistor unit connected in series with the transceiver unit, wherein the first limiting unit is connected in parallel with transceiver unit and to a control terminal of the transistor and is configured to control an input voltage for the control terminal of the transistor to a predeterminable control value such that the input voltage of the transceiver unit is limited to the first transceiver voltage value.

The present disclosure provides a voltage reference source circuit for generating a reference voltage, the voltage reference source circuit comprises a starting circuit, a current generating circuit, and an output voltage reference circuit electrically connected in sequence. The starting circuit provides a starting voltage for the voltage reference source circuit to prevent the voltage reference source circuit from operating in zero state area. The current generating circuit generates a working current for the output voltage reference circuit; and the output voltage reference circuit is used to realize the reference voltage output with zero temperature coefficient according to the working current output by the current generating circuit. A low power consumption power supply system is also disclosed. The voltage reference source circuit and the low power consumption power supply system with the voltage reference source circuit have simple circuit structure, strong anti-noise ability, high stability and high performance.

The present disclosure provides a voltage reference source circuit for generating a reference voltage, the voltage reference source circuit comprises a starting circuit, a current generating circuit, and an output voltage reference circuit electrically connected in sequence. The starting circuit provides a starting voltage for the voltage reference source circuit to prevent the voltage reference source circuit from operating in zero state area. The current generating circuit generates a working current for the output voltage reference circuit; and the output voltage reference circuit is used to realize the reference voltage output with zero temperature coefficient according to the working current output by the current generating circuit. A low power consumption power supply system is also disclosed. The voltage reference source circuit and the low power consumption power supply system with the voltage reference source circuit have simple circuit structure, strong anti-noise ability, high stability and high performance.

A low-temperature drift ultra-low-power linear regulator includes eight PMOS transistors, two resistors, two capacitors and three NMOS transistors. The eight PMOS transistors include PMOS transistor PM1 to PMOS transistor PM8. The two resistors include resistor R1 and resistor R2. The two capacitors include capacitor C1 and capacitor C2. The three NMOS transistors include NMOS transistor NM1, NMOS transistor NM2 and NMOS transistor NM3. From right to left, the linear regulator includes a PTAT voltage core starting circuit, a PTAT voltage core circuit, a negative temperature characteristic generating circuit and a driver stage closed-loop control circuit. PM5-PM8 form a feedback circuit. The feedback circuit clamps the current flowing through PM6 to be proportional to PM2 to obtain a temperature-stable output voltage, and can dynamically adjust the gate voltage of PM5 according to the change of load current to output different currents according to the load demand.

A low-temperature drift ultra-low-power linear regulator includes eight PMOS transistors, two resistors, two capacitors and three NMOS transistors. The eight PMOS transistors include PMOS transistor PM1 to PMOS transistor PM8. The two resistors include resistor R1 and resistor R2. The two capacitors include capacitor C1 and capacitor C2. The three NMOS transistors include NMOS transistor NM1, NMOS transistor NM2 and NMOS transistor NM3. From right to left, the linear regulator includes a PTAT voltage core starting circuit, a PTAT voltage core circuit, a negative temperature characteristic generating circuit and a driver stage closed-loop control circuit. PM5-PM8 form a feedback circuit. The feedback circuit clamps the current flowing through PM6 to be proportional to PM2 to obtain a temperature-stable output voltage, and can dynamically adjust the gate voltage of PM5 according to the change of load current to output different currents according to the load demand.

Provided is a logarithmic current-to-voltage conversion circuit having a temperature compensation function. The circuit includes a logarithmic current-to-voltage conversion buffer unit, a positive temperature coefficient compensation unit and a self-heating unit. The logarithmic current-to-voltage conversion buffer unit is provided with a reference circuit consistent with a basic logarithmic circuit. A temperature coefficient is reflected by a difference value ΔVbe between an output of the basic logarithmic circuit and an output of the reference circuit. The positive temperature coefficient compensation unit is provided with a voltage-to-current conversion circuit at a first stage and a current mirror at a second stage and outputs a voltage Vout through an resistor R2. The positive temperature coefficient compensation unit is connected to ΔVbe. The voltage-to-current conversion circuit is provided with a resistor R0 and an adjustable resistor R1 connected in series, where a temperature coefficient of (R1+R0)/R2 is corrected by adjusting a value of the adjustable resistor R1.

A reference signal generator having high order temperature compensation includes: first and second transistors generating a proportional to absolute temperature (PTAT) signal and at least one complementary to absolute temperature (CTAT) signal according to at least one bandgap related to the first and second transistors; a feedback network coupled to the first and second transistors; an amplifier circuit configured to linearly superimpose the PTAT signal and the CTAT signals via the feedback network, to generate a reference signal; a second order adjustment circuit including a third transistor controlled by a bias voltage, to generate an adjustment current for adjusting the reference signal; and a third order adjustment circuit configured to adjust the bias voltage according to a temperature under test, for adjusting the adjustment current, to adjust the reference signal, such that a variation of the reference signal is smaller than a predetermined variation range within a temperature range.

A reference signal generator having high order temperature compensation includes: first and second transistors generating a proportional to absolute temperature (PTAT) signal and at least one complementary to absolute temperature (CTAT) signal according to at least one bandgap related to the first and second transistors; a feedback network coupled to the first and second transistors; an amplifier circuit configured to linearly superimpose the PTAT signal and the CTAT signals via the feedback network, to generate a reference signal; a second order adjustment circuit including a third transistor controlled by a bias voltage, to generate an adjustment current for adjusting the reference signal; and a third order adjustment circuit configured to adjust the bias voltage according to a temperature under test, for adjusting the adjustment current, to adjust the reference signal, such that a variation of the reference signal is smaller than a predetermined variation range within a temperature range.