A low-power CMOS reference voltage generating with enhanced power supply rejection ratio (PSRR) and fast start-up time is disclosed. The reference voltage generating is generated by the stacked diode-connected MOS transistors (SDMT) architecture to reduce the dependence on process, voltage and temperature. The self-biased and capacitor coupled architecture can shorten the start-up time without increasing power consumption and improve the bandwidth of the power supply rejection ratio. This design is implemented using a CMOS process, which can achieve stabilization time of 0.2 ms. Under the same power consumption, this design is 274 times better than a design without a start-up time enhancement. The power supply rejection ratio measured at 100 Hz is −73.5 dB. In the temperature range of −40 to 130° C., the average temperature coefficient is 62 ppm/° C.

Voltage reference circuits are provided. A voltage reference circuit includes a first transistor, a flipped-gate transistor, a first current mirror unit, a second current mirror unit, and an output note. The first transistor is formed by a plurality of second transistors. A gate and a drain of the flipped-gate transistor are coupled to a gate and a drain of each second transistor. The first current mirror unit is configured to provide a first current to the flipped-gate transistor and a mirroring current in response to a bias current. The second current mirror unit is configured to drain a second current from the first transistor in response to the mirroring current. The output node is coupled to a source of each second transistor and the second current mirror unit, and configured to output a reference voltage. Size of the flipped-gate transistor is less than that of the first transistor.

An apparatus can include tracking circuitry coupled to a current source and configured to generate a reference voltage signal based on a reference current signal from the current source. The apparatus can include voltage regulator circuitry coupled to the tracking circuitry and configured to generate a voltage supply signal based on the reference voltage signal. The apparatus can further include amplifier circuitry configured to amplify an input signal based on the voltage supply signal. The reference voltage signal can track process and temperature variations associated with at least one field effect transistor within the tracking circuitry. The voltage regulator circuitry can be configured to operate with a closed loop gain higher than 1. The tracking circuitry includes a first transistor connected in parallel with a second transistor, the first and second transistors having a complimentary type with each other (e.g., NMOS and PMOS transistors).

Provided is a semiconductor device with a reference voltage circuit including an enhancement type transistor having P-type polycrystalline silicon as a first gate electrode, and a depletion type transistor having N-type polycrystalline silicon as a second gate electrode, in which the enhancement type transistor has an impermeable film that is locally provided to cover the first gate electrode via an interlayer insulating film disposed on the first gate electrode, and a nitride film that has an opening portion which is provided larger than the first gate electrode and smaller than the impermeable film, and is provided to cover a periphery of the impermeable film, and the depletion type transistor has a nitride film that is directly provided on an interlayer insulating film disposed on the second gate electrode and covers the depletion type transistor without a gap.

The present disclosure provides a differential reference voltage buffer, including: a buffer stage, including at least a first transistor and a second transistor; a control circuit, connected with the buffer stage and forming a negative feedback structure for generating a differential reference voltage; a current compensation circuit for compensating a resistive load current of the control circuit; and a drive stage for generating an output differential reference voltage. The differential reference voltage is generated according to an external input reference voltage and a common mode input voltage. The common mode voltage can be set separately, so that the flexibility is high. The current generated by a resistive network in the control circuit is compensated by the current compensation circuit, so that the current of a follow device in the buffer stage is not influenced by the control circuit, thereby generating a differential reference voltage with high accuracy output.

An all-MOSFET voltage reference circuit includes a first cascaded branch configured to generate a bias current and composed of a first current source and a diode-connected first N-type transistor connected at a first interconnected node; a second cascaded branch composed of a second current source, a diode-connected second N-type transistor and a third N-type transistor connected with the second N-type transistor disposed in between, wherein the second N-type transistor and the third N-type transistor are connected at a second interconnected node; a third cascaded branch composed of a third current source and a diode-connected fourth N-type transistor connected at an output node that provides a reference voltage; and an amplifier with a non-inverting node coupled to the first interconnected node and an inverting node coupled to the second interconnected node. A threshold voltage of the third N-type transistor is larger than a threshold voltage of the second N-type transistor.

A controllable temperature coefficient bias (CTCB) circuit is disclosed. The CTCB circuit can provide a bias to an amplifier. The CTCB circuit includes a variable with temperature (VWT) circuit having a reference circuit and a control circuit. The control circuit has a control output, a first current control element and a second current control element. Each current control element has a “controllable” resistance. One of the two current control elements may have a relatively high temperature coefficient and another a relatively low temperature coefficient. A controllable resistance of one of the current control elements increases when the controllable resistance of the other current control element decreases. However, the “total resistance” of the current control circuit remains constant with a constant temperature. The VWT circuit has an output with a temperature coefficient that is determined by the relative amount of current that flows through each current control element of the control circuit. A Current Digital to Analog Converter (IDAC) scales the output of the VWT and provides the scaled output to an amplifier bias input.

Apparatus and methods for compensating supply sensitive circuits for supply voltage variation are provided. In certain embodiments, an electronic system includes a power supply that outputs a supply voltage having a nominal voltage level, a supply conductor for routing the supply voltage, and a group of integrated circuits (ICs) that each receive the supply voltage from the supply conductor. Each IC includes a supply sensing circuit that generates a sense signal based on a local voltage level of the supply voltage at the IC, a bias control circuit that adjusts a bias signal based on the sense signal to account for a difference between the nominal voltage level and the local voltage level of the supply voltage, and a signal processing circuit biased by the bias signal.

A voltage reference circuit comprises: a first transistor; a second transistor, wherein the first transistor and the second transistor are arranged in a stacked connection between a terminal connected to ground and a terminal connected to a supply voltage, wherein a reference voltage is output at an output node between the first transistor and the second transistor; and a regulating transistor, wherein the regulating transistor is connected between the supply voltage and the first transistor in a stacked connection with the second transistor, wherein a bulk terminal of the regulating transistor is connected to the output node for compensating changes in the reference voltage at the output node to maintain a stable reference voltage level.

A voltage reference circuit comprises: first transistor, second transistor, first regulating transistor, and second regulating transistor arranged in a stacked connection, wherein first voltage is provided at first node between first and second transistor, second voltage is provided at second node between second transistor and first regulating transistor, third voltage is provided at third node between first and second regulating transistor; wherein first regulating transistor and second regulating transistor are connected to first node and second node, respectively, for compensating changes in first voltage and second voltage, respectively, to maintain stable voltage levels; wherein voltage reference circuit outputs at least one of the first, second or third voltage as a reference voltage.