Abstract: Systems and methods are disclosed to provide for low power operation of a back-up power supply. In one aspect, a back-up power supply system may include a switch system, such as a voltage regulator, that is coupled to provide an output voltage for charging a back-up power device up to about a predetermined voltage based on an input voltage. A charge pump is coupled to provide a pump voltage to the output voltage for charging the back-up power device up to about the predetermined voltage based on the output voltage exceeding the input voltage.

Abstract: A differential input comparator circuit comprises an input stage comprising dual polarity input voltages and an output stage adapted to output a differential voltage based on the input voltages, wherein the differential voltage is adapted to be transmitted to a comparator and wherein the circuit has high input impedance and works with high input voltage swings.

Abstract: An amplifier providing a drive signal indicative of a data input signal to a capacitive and/or resistive type load, the amplifier having a first transistor circuit adapted for converting the data input signal to a corresponding current signal in which the transistors of the first transistor circuit operate at a first voltage and having a second transistor circuit amplifying the current signal in which the transistors of the second transistor circuit operate at a second voltage. The first transistor circuit and the second transistor circuit are integrated for providing a class AB operable current output to the load.