Abstract: Techniques to use reservoir capacitors in ADC to supply most of the charge to bit-trial capacitors as bit-trials are performed. An accurate reference voltage source, e.g., a reference buffer circuit, only needs to supply the difference, e.g., an inaccuracy, in the charge supplied by the reservoir capacitors. Instead of having to resettle for each bit-trial, the accurate reference voltage source has only to deliver the initial charge to the reservoir capacitors during acquisition and once more when the ADC is ready to sample onto the residue amplifier. These techniques can ease the demands on the reference buffer circuit and requirement of external decoupling capacitors, for example.

Abstract: The present disclosure relates to a voltage reference circuit and a method of providing a voltage reference. The voltage reference circuit uses a switched capacitor arrangement to move charge between capacitors during different phases of operation of the circuit to which the voltage reference is being provided. The circuit being provided with a voltage reference may be an analog-to-digital converter (ADC). A reservoir capacitor is used to supply the reference voltage. During a phase in which no voltage reference is required, charge is shared between the capacitors of the switched capacitor arrangement, in order to boost the charge on the reservoir capacitor. After charge sharing, the reservoir capacitor is topped up with an output from a reference buffer. The reservoir capacitor may then be used again in the next conversion phase.

Abstract: In an example embodiment, an amplifier having high gain and high slew rate is provided and includes a pair of input transistors to which input voltage is applied, a pair of diode-connected loads coupled to the input transistors, at least one pair of current sources coupled to the diode-connected loads, and a bias control configured to turn off the at least one pair of current sources to enable high slew rate for the amplifier and to turn on the at least one pair of current sources to enable high gain for the amplifier. In specific embodiments, the current sources include transistors, the bias control controls a bias voltage to the current sources, and the bias voltage is driven to the supply voltage (VDD) to turn off the current sources.

Abstract: In an example embodiment, an amplifier having high gain and high slew rate is provided and includes a pair of input transistors to which input voltage is applied, a pair of diode-connected loads coupled to the input transistors, at least one pair of current sources coupled to the diode-connected loads, and a bias control configured to turn off the at least one pair of current sources to enable high slew rate for the amplifier and to turn on the at least one pair of current sources to enable high gain for the amplifier. In specific embodiments, the current sources include transistors, the bias control controls a bias voltage to the current sources, and the bias voltage is driven to the supply voltage (VDD) to turn off the current sources.