An operational amplifier includes a first differential input pair, a first switch and a second switch. The first differential input pair includes a first input transistor and a second input transistor. The first input transistor has a gate terminal coupled to an output terminal of the operational amplifier. The second input transistor has a gate terminal. The first switch is coupled between the gate terminal of the first input transistor and the gate terminal of the second input transistor. The second switch is coupled between a first input terminal of the operational amplifier and the gate terminal of the second input transistor.

A level shifter, a digital-to-analog converter (DAC), and a buffer amplifier, and a source driver and an electronic device including the same are provided. The source driver includes a level shifter configured to receive digital bits and provide a level-shifted output signal; a DAC including a resistor string configured to provide a plurality of gradation voltages formed by an upper limit voltage and a lower limit voltage being received through one end and the other end, and an N-type metal oxide semiconductor (NMOS) switch and a P-type MOS (PMOS) switch configured to be controlled by the level-shifted output signal and output a gradation voltage corresponding to the level-shifted output signal; and an amplifier configured to amplify a signal provided by the digital-to-analog converter, and the lower limit voltage is provided to a body electrode of the NMOS switch.

A level shifter, a digital-to-analog converter (DAC), and a buffer amplifier, and a source driver and an electronic device including the same are provided. The source driver includes a level shifter configured to receive digital bits and provide a level-shifted output signal; a DAC including a resistor string configured to provide a plurality of gradation voltages formed by an upper limit voltage and a lower limit voltage being received through one end and the other end, and an N-type metal oxide semiconductor (NMOS) switch and a P-type MOS (PMOS) switch configured to be controlled by the level-shifted output signal and output a gradation voltage corresponding to the level-shifted output signal; and an amplifier configured to amplify a signal provided by the digital-to-analog converter, and the lower limit voltage is provided to a body electrode of the NMOS switch.

A programmable resistance circuit provides a selected resistance by configuring a reference resistor to exhibit an effective resistance, in an operational sense, by achieving an average output voltage between a source line and a return line in the programmable resistance circuit. The average output voltage corresponds to the effective resistance. The effective resistance is achieved by utilizing a modulated voltage source to bias a transistor and intermittently draw current across the reference resistor according to the duty cycle of the modulated voltage source. A programmed resistance circuit can produce a selected resistance corresponding to button selection zones of a vehicle user interface when connected to a remote circuit that acts according to a user selection.

A programmable resistance circuit provides a selected resistance by configuring a reference resistor to exhibit an effective resistance, in an operational sense, by achieving an average output voltage between a source line and a return line in the programmable resistance circuit. The average output voltage corresponds to the effective resistance. The effective resistance is achieved by utilizing a modulated voltage source to bias a transistor and intermittently draw current across the reference resistor according to the duty cycle of the modulated voltage source. A programmed resistance circuit can produce a selected resistance corresponding to button selection zones of a vehicle user interface when connected to a remote circuit that acts according to a user selection.

An analog-to-digital converter (ADC) and an operation method thereof are provided. The ADC includes: a comparator which compares a signal input through a first input terminal and a signal input through a second input terminal, and outputs an output value according to the comparison result. A successive approximation register receives the output value of the comparator, sets digital signal values from a most significant bit to a least significant bit, and outputs the digital signal values. A digital-to-analog converter receives the digital signal values, and converts it into an analog signal based on a reference voltage Vref, and outputs it to the second input terminal. A noise component is added to the input signal and to the analog signal Vdac′.

Certain aspects of the present disclosure provide a digital-to-analog converter (DAC) system. The DAC system generally includes a plurality of current steering cells, each comprising a current source coupled to at least two current steering switches, wherein control inputs of the at least two current steering switches are coupled to an input path of the DAC system. The DAC system may also include a current source toggle circuit configured to selectively disable the current source of at least one of the plurality of current steering cells, and a feedforward path coupled between the input path and at least one control input of the current source toggle circuit.

Circuitry is disclosed herein that dynamically (temperature-invariant and voltage-invariant) adjusts the Ron of switches in a resistive Nyquist-rate digital to analog converter (DAC) to thereby reduce DAC nonlinearity errors and improve INL results of greater than 16b. Consistent with the present disclosure, the DAC includes an R-2R ladder in which each bit corresponds to a switch. A control circuit is provided for generating signals applied to the gate of the switch to cause the on-resistances of the switch to be a particular value, such that the on-resistance of the switch plus the sum of two resistors, one having the resistance R, and the other having a resistance R′ is equivalent to the resistance of the 2R-size resistors or twice the resistance of the R-sized resistors in the ladder.

A voltage-divider circuit, including: a network of discrete resistors defining T tiers of resistors, where T≥2, the T tiers comprising first and subsequent tiers, the Xth tier including at least one Xth-tier resistor where X=1, and the Xth tier including at least two Xth-tier resistors for each value of X in the range 2≤X≤T, wherein, for each value of X in the range 1≤X<T: each Xth-tier resistor is connected between a pair of nodes of the voltage-divider circuit at which a relatively high and low voltage signal are provided, respectively; at least one Xth-tier resistor is implemented as a subdivision network of discrete resistors; and for each Xth-tier resistor implemented as a subdivision network, that subdivision network includes a main resistor connected in series with a corresponding auxiliary resistor, that main resistor implemented as a base resistor connected in parallel with a series connection of a plurality of X+1th-tier resistors.

A voltage-divider circuit, including: a network of discrete resistors defining T tiers of resistors, where T≥2, the T tiers comprising first and subsequent tiers, the Xth tier including at least one Xth-tier resistor where X=1, and the Xth tier including at least two Xth-tier resistors for each value of X in the range 2≤X≤T, wherein, for each value of X in the range 1≤X<T: each Xth-tier resistor is connected between a pair of nodes of the voltage-divider circuit at which a relatively high and low voltage signal are provided, respectively; at least one Xth-tier resistor is implemented as a subdivision network of discrete resistors; and for each Xth-tier resistor implemented as a subdivision network, that subdivision network includes a main resistor connected in series with a corresponding auxiliary resistor, that main resistor implemented as a base resistor connected in parallel with a series connection of a plurality of X+1th-tier resistors.