Configurable switched capacitor block
AssigneeCypress Semiconductor Corporation
InventorsEashwar Thiagarajan, Harold Kutz
Life of this patent
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Abstract
A configurable switched capacitor block includes a switched-capacitor (SC) sampling circuit, a fully differential amplifier, an SC feedback circuit, and a comparator. The SC sampling circuit is coupled to receive an input signal and to selectively generate a sampled signal to a differential input of the amplifier. The SC feedback circuit is coupled between the differential inputs and the differential outputs of the amplifier to selectively control a feedback of the amplifier. The comparator is coupled to the differential outputs of the amplifier to generate an output signal. The configurable switched capacitor block has multiple modes of operation which are selectable by programming the SC sampling circuit and the SC feedback circuit.
Claims14
An apparatus comprising:
- a switched-capacitor (SC) sampling circuit configured to receive an input signal and to selectively generate a sampled signal;
- an amplifier having differential input and differential outputs, wherein the differential inputs comprise a non-inverting and an inverting input configured to receive the sampled signal, and wherein the SC sampling circuit includes:
- a first and a second input port;
- a first input capacitor coupled between the input port and the non-inverting input of the amplifier;
- a second input capacitor coupled between the second input port and the inverting input of the amplifier;
- and
- a first cross-connect switch to selectively couple the first and second input capacitors together;
- an SC feedback circuit coupled between the differential inputs and the differential outputs to selectively control a feedback of the amplifier, wherein the SC feedback circuit comprises a feedback switch and a feedback variable capacitor coupled in series between the differential inputs and the differential outputs of the amplifier;
- and
- a comparator coupled to the differential outputs of the amplifier, wherein the SC sampling circuit and the SC feedback circuit are programmable to select between multiple analog functions of the apparatus;
- wherein the multiple analog functions comprises at least two analog functions selected from the group consisting of:
- an amplifier function, an integrator function, a comparator function, a modulator function, a variable gain amplifier function, a variable gain integrator function, a variable gain comparator function, and a variable gain modulator function.
A method comprising:
- setting a control register coupled to a switched-capacitor (SC) block;
- configuring an SC feedback circuit of the SC block to selectively control the feedback of an amplifier of the SC block in response to setting the control register;
- configuring an SC sampling circuit coupled to receive an input signal and to selectively output a sampled signal to the amplifier in response to setting the control register, wherein configuring the SC feedback circuit and SC sampling circuit includes selecting between multiple analog functions of the SC block, wherein the SC sampling circuit comprises a first and a second input port;
- and
- configuring an input multiplexer to selectively couple any of a plurality of input lines to the first and second input ports.
A switched capacitor block comprising:
- means for receiving an input signal and selectively generating a sampled signal;
- means for amplifying the sampled signal, said means for amplifying having differential inputs and differential outputs, wherein the differential inputs are coupled to receive the sampled signal;
- means for selectively controlling a feedback of the means for amplifying;
- means for comparing the differential output of the means for amplifying;
- means for selecting between multiple analog functions of the switched capacitor block;
- means for alternately enabling and disabling a plurality of switched variable capacitors;
- and
- means for setting a capacitance value for at least one of the plurality of switched variable capacitors.
Dependencies are inferred from the claim text.