Active power supply ripple filter

摘要

An active power supply ripple filter with low noise and low power dissipation characteristics, which tracks the voltage of the power source with low voltage drop and high current capability. The circuit consists of a control transistor connected between one terminal of a power source and one terminal of a load, a reference circuit which tracks the supply voltage, a low pass filter which filters the reference voltage and an amplifier for driving the control transistor in response to the filtered reference voltage and a feedback voltage from the load. The circuit minimizes the voltage drop across the control transistor as well as minimizing the capacitance values required for the filter capacitors.