摘要:
A signal processing integrated circuit has having a chopper stabilized, multistage, feedforward amplifier and a delta sigma analog to digital converter. Filtering of the output of the output from the analog to digital converter comprises a sinc5 filter and a sinc3 filter. The sinc3 filter may be bypassed. A rough buffer permits quick charging of a sample and hold capacitor during part of the charge cycle and slower but more accurate charging during the remainder of the charge cycle.
摘要:
A buffer arrangement uses separate amplifiers for handling for positive going signal transitions and for negative going signal transitions respectively. A comparator detects the direction of transition and a switching element connects signal input lines in the appropriate sense to the respective amplifiers based on the output of the comparator. This permits amplifiers optimized for positive or negative going transitions to be used. The output of the amplifiers can be connected across a sampling capacitor
摘要:
A digital to analog converter utilizes two discrete time processing stages, such as switched capacitor integrator circuits, operating at different sampling rates when converting the digital input signal to an analog signal. Use of two different sampling rates relaxes the requirements on antialias filters used in the continuous time processing.
摘要:
A integrated circuit digital to analog converter converts an M-bit digital signal to an analog output signal. The analog output signal can be used to drive external devices such as an off-chip driver. The output of the external device is sampled and fed back across the discrete time/continuous time interface on the chip to the input of the analog to digital converter. Taking the feedback point after the external device ensures relatively high performance for noise and linearity using relatively low performance components, both on and off the chip.
摘要:
A digital to analog converter converts an N-bit digital signal into an M-bit digital signal and provides the M-bit digital signal to a conversion circuit which converts the M-bit signal to an analog output signal. The analog output signal is sampled and fed back across the discrete time/continuous time interface to the input of the conversion circuit. An interpolation filter is used to increase the apparent sampling rate of the incoming N-bit signal.
摘要:
A 1-bit digital to analog converter uses both discrete time and continuous time processing to produce an analog output signal. The analog output signal is sampled and fed back across the discrete time/continuous time interface to the input of the conversion circuit. In one implementation, the discrete time processing uses an integrator chain of switched capacitor integrators and a switched capacitor low pass filter. The continuous time processor is a 2 pole low pass filter. A finite impulse response filter can precede the discrete time processing. A plurality of analog output sampling arrangements can be selectively applied accommodate a variety of operational conditions.
摘要:
An amplifier is disclosed including at least three integrator stages connected to provide a low-frequency path from a signal input to a signal output, and a relatively high-frequency bypass path around the first integrator stage. The first integrator stage uses dynamic offset reduction such as chopper stabilization, and an analog low-pass filter reduces artifacts of the dynamic offset reduction. The paths converge at a current summing node. To prevent instability when the integrators are saturated by large signals, the paths have respective saturation current limits selected so that the relatively high-frequency path is not saturated when the low-frequency path saturates. To ensure that the conditional stability is substantially unaffected by adjustment of closed-loop gain, a current feedback input adjusts the open-loop gain in a fashion inversely proportional to resistance presented to the current feedback input by a feedback circuit.
摘要:
In an embodiment, a method includes: during a first portion of a cycle of a clock signal generated by an oscillator, pre-charging a first capacitor of a first switched capacitor stage until a first comparator determines that a first node voltage of the first switched capacitor stage is greater than a first reference voltage at a first reference voltage node; applying a second reference voltage to the first reference voltage node; and responsive to a first edge of the clock signal, charging the first capacitor until the first comparator determines that the first node voltage is greater than the second reference voltage at the first reference voltage node.
摘要:
A circuit includes a comparator including a first input, a second input, and an output. The circuit further includes a plurality of capacitive sampling circuits configured to be selectively coupled to the first and second inputs. Each of the plurality of capacitive sampling circuits includes first and second capacitors, and includes first and second conversion switches configured to selectively couple the first and second capacitors to the first and second inputs, respectively. The first and second conversion switches of a selected one of the plurality of capacitive sampling circuits are closed to couple the selected one to the first and second inputs of the comparator during a conversion phase.
摘要:
A circuit includes a comparator including a first input, a second input, and an output. The circuit further includes a plurality of capacitive sampling circuits configured to be selectively coupled to the first and second inputs. Each of the plurality of capacitive sampling circuits includes first and second capacitors, and includes first and second conversion switches configured to selectively couple the first and second capacitors to the first and second inputs, respectively. The first and second conversion switches of a selected one of the plurality of capacitive sampling circuits are closed to couple the selected one to the first and second inputs of the comparator during a conversion phase.