An implementation of an operational amplifier circuit includes a first stage amplifier circuit, a second stage amplifier circuit and a first feedforward circuit. The first stage amplifier circuit is coupled to a first input node for receiving a first input signal and amplifying the first input signal to generate a first amplified signal. The second stage amplifier circuit is coupled to the first stage amplifier circuit for receiving the first amplified signal and amplifying the first amplified signal to generate a first output signal at a first output node. The first feedforward circuit is coupled between the first input node and the second stage amplifier circuit for feeding the first input signal forward to the second stage amplifier circuit.

An output buffer with an offset cancellation structure for an LCD source driver includes an operational amplifier, for driving an output signal of the output buffer according to a data signal from a data input terminal of the output buffer; a reference voltage generator, for generating a reference voltage and inputting the reference voltage to the operational amplifier; and a sampling capacitor, coupled between a second input terminal of the operational amplifier and the data input terminal of the output buffer in a first phase, and coupled between the second input terminal of the operational amplifier and an output terminal of the operational amplifier in a second phase, wherein the second input terminal of the operational amplifier is further coupled to the output terminal of the operational amplifier in the first phase. The output signal outputs the data signal where the offset voltage is cancelled in the second phase.

This application relates to methods and apparatus for switched mode drivers. A BTL driver has a switch network operable in different switch states, wherein, in each switch state, each of first and second output nodes is connected to a respective one of a first switching voltage, a second switching voltage or an intermediate switching voltage between the first and second switching voltages which is provided by a driver capacitance. A controller is configured to control the switch network to operate in a sequence of switch states to generate a differential drive signal based on an input signal. The controller is configured such that operation of driver switch network in said sequence of switch states to generate said differential drive signal provides voltage regulation of the intermediate voltage provided by said driver capacitance.