Patent classifications
H03F2203/45616
OFFSET VOLTAGE CANCELATION FOR A CHARGE AMPLIFICATION CIRCUIT
A circuit includes an amplifier, a bias voltage node, and a first set of switches configured, based on a first reset signal being asserted, to couple amplifier input nodes to the bias voltage node and to short-circuit amplifier output nodes. First and second feedback branches each include a respective circuit network including parallel capacitors, with first ones of the capacitors directly connected to the amplifier input nodes. The first and second feedback branches further include a second set of switches intermediate the amplifier input nodes and second ones of the capacitors, and a third set of switches intermediate amplifier output nodes and the capacitors. These switches selectively couple the capacitors to the amplifier input and output nodes, based on a second reset signal being asserted. The second reset signal is asserted for a time interval exceeding a time interval in which the first reset signal is asserted.
Play mute circuit and method
In an embodiment, an amplifier circuit includes a second stage that includes a first switch circuit including first and second terminals, a plurality of resistive elements coupled between the first and second terminals of the first switch circuit, and a plurality of switches configured to control an equivalent resistance between the first and second terminals of the first switch circuit. During play mode, the second stage has a gain between the input of the second stage and the output of the second stage of a first value. During a transition from mute mode to play mode, the amplifier circuit is configured to progressively increase the gain of the second stage from a second value to the first value. During a transition from play mode to mute mode, the amplifier circuit is configured to progressively decrease the gain of the second stage from the first value to the second value.
Offset voltage cancelation for a charge amplification circuit
A circuit includes an amplifier, a bias voltage node, and a first set of switches configured, based on a first reset signal being asserted, to couple amplifier input nodes to the bias voltage node and to short-circuit amplifier output nodes. First and second feedback branches each include a respective circuit network including parallel capacitors, with first ones of the capacitors directly connected to the amplifier input nodes. The first and second feedback branches further include a second set of switches intermediate the amplifier input nodes and second ones of the capacitors, and a third set of switches intermediate amplifier output nodes and the capacitors. These switches selectively couple the capacitors to the amplifier input and output nodes, based on a second reset signal being asserted. The second reset signal is asserted for a time interval exceeding a time interval in which the first reset signal is asserted.