A flicker-free LED driving apparatus and voltage regulating method thereof are disclosed. The apparatus includes a power conversion circuit receiving an AC electricity and then generating an output voltage with a ripple component for an LED string; a feedback circuit electrically connected to the power conversion circuit and generating a feedback signal with varying duty cycle according to operation states of the LED string; a power conversion circuit including, a controller receiving the feedback signal turns on or off a switching device thereof according to the feedback signal; and a linear voltage-regulating circuit electrically connected to the power conversion circuit, the feedback circuit, and the LED string. and configured to regulate the output voltage in accordance with a voltage difference between the output voltage and a voltage across the LED string.

A voltage regulator apparatus with a rejection capability for high frequency power noise includes a low dropout linear regulator and a noise rejection circuit. The low dropout linear regulator has at least one operational amplifier which is powered by a power source, and the low dropout linear regulator is configured for receiving and regulating an input voltage signal to provide an output voltage signal for a load. The noise rejection circuit is coupled between the power source and the low dropout linear regulator, and is configured for providing a power noise rejection capability upon a high frequency part of a power signal of the power source to generate the power signal with less high frequency noise to the at least one operational amplifier.

A voltage regulator apparatus with a rejection capability for high frequency power noise includes a low dropout linear regulator and a noise rejection circuit. The low dropout linear regulator has at least one operational amplifier which is powered by a power source, and the low dropout linear regulator is configured for receiving and regulating an input voltage signal to provide an output voltage signal for a load. The noise rejection circuit is coupled between the power source and the low dropout linear regulator, and is configured for providing a power noise rejection capability upon a high frequency part of a power signal of the power source to generate the power signal with less high frequency noise to the at least one operational amplifier.

A voltage regulator is equipped with the first and the second source-grounded amplifier circuits connected to an output terminal of a differential amplifier circuit; a phase compensation circuit having a resistor part and a capacitor part, and connected between an output terminal of the first source-grounded amplifier circuit and an output terminal of the second source-grounded amplifier circuit; and an output transistor connected to the output terminal of the second source-grounded amplifier circuit. At least one of the resistor part and the capacitor part of the phase compensation circuit has a filter.

A low-dropout (LDO) voltage regulator includes an adaptive bias source for generating a bulk-bias signal to a pass device in the LDO voltage regulator, wherein the adaptive bias source generates the bulk-bias signal based on a signal obtained at an output of the LDO voltage regulator. The signal includes a current signal, which is proportional to a current at the output of the LDO voltage regulator, and/or a feedback signal from a feedback path connected between the adaptive bias source and the output of the LDO voltage regulator for sensing negative and/or positive spikes.

A voltage regulator that provides feedforward cancellation of power supply noise is disclosed. The voltage regulator includes a process tracking circuit that receives a supply voltage and generates a proportional voltage. A tracking capacitor is coupled to the process tracking circuit and generates an injection voltage based on the proportional voltage. An Ahuja compensated regulator generates a regulated voltage. The injection voltage is provided on a feedback path of the Ahuja compensated regulator.

In accordance with a first aspect of the present disclosure, a voltage regulator is provided, comprising: a core and an output stage configured to be coupled to the core, wherein said output stage comprises a set of output stage units; a switch unit comprising a plurality of controllable switches, wherein said controllable switches are configured to couple subsets of the set of output stage units to the core. In accordance with a second aspect of the present disclosure, a corresponding method of configuring a voltage regulator is conceived.

Disclosed is a voltage regulator. The voltage regulator includes a reference voltage circuit, a noise cancellation circuit, an error amplifier, a pass transistor and a voltage divider. The voltage regulator can cancel the noise generated by the reference voltage circuit and the error amplifier, and also can improve its Power Supply Rejection Ratio (PSRR).

A voltage regulating circuit provides a feedback voltage and an output voltage based on a power voltage. The voltage regulating circuit includes a reference voltage generator and a compensating circuit. The reference voltage generator receives the power voltage, produces the feedback voltage, and includes an impedance having first and second terminals. The second terminal is coupled to a ground voltage and a first current flows through the impedance at the first terminal to produce the feedback voltage. The compensating circuit includes a negative threshold voltage (NVT) transistor having a source terminal, a drain terminal and a gate terminal. The source terminal receives a power voltage, the drain terminal is connected to the gate terminal and coupled to the first terminal of the impedance through a path to add a second current to the first current when the NVT transistor is turned on under an operational condition at the FF corner.

A voltage regulating circuit provides a feedback voltage and an output voltage based on a power voltage. The voltage regulating circuit includes a reference voltage generator and a compensating circuit. The reference voltage generator receives the power voltage, produces the feedback voltage, and includes an impedance having first and second terminals. The second terminal is coupled to a ground voltage and a first current flows through the impedance at the first terminal to produce the feedback voltage. The compensating circuit includes a negative threshold voltage (NVT) transistor having a source terminal, a drain terminal and a gate terminal. The source terminal receives a power voltage, the drain terminal is connected to the gate terminal and coupled to the first terminal of the impedance through a path to add a second current to the first current when the NVT transistor is turned on under an operational condition at the FF corner.