A switched-capacitor integrator is an electronic circuit used to perform the mathematical operation of integration on an input signal. It is widely used in analog signal processing, especially in analog-to-digital converters (ADCs), filters, and other applications where analog signals need to be manipulated.
The basic principle behind a switched-capacitor integrator involves periodically charging and discharging capacitors using switches controlled by clock signals. The input signal is applied to the capacitor during the charging phase, and the integration is achieved by accumulating charge over time. The key advantage of this approach is that it allows the use of capacitors to implement the integration function, instead of more complex and space-consuming resistor-capacitor (RC) networks.
The operation of a switched-capacitor integrator can be divided into two main phases:
Sampling Phase: During this phase, the switches are closed, connecting the input signal to the capacitor. The capacitor charges up to the voltage level of the input signal. This phase is typically short and governed by a clock signal.
Reset Phase: In this phase, the switches are opened, disconnecting the capacitor from the input signal, and connecting it to a reset voltage (usually ground). As a result, the capacitor's voltage is reset to its initial value.
The integration occurs over multiple cycles of sampling and resetting. The accumulated charge on the capacitor represents the integral of the input signal over time, which is equivalent to the area under the input signal curve.
By adjusting the frequency of the clock signal and the capacitor values, the integration time (the duration over which the input signal is integrated) can be controlled. Additionally, switched-capacitor integrators can be designed to offer high linearity, accuracy, and low drift compared to traditional continuous-time integrators.
Overall, switched-capacitor integrators are essential components in many analog signal processing systems, providing an efficient and flexible way to perform integration in integrated circuits.