How to design a capacitance multiplier for power supply?

How to design a capacitance multiplier for power supply?

In terms of design and layout, you can easily design a capacitance multiplier from discrete components or an operational amplifier IC. This circuit causes a capacitor to behave like a much larger capacitor, which provide much better smoothing in power supply circuits.

How is a capacitance multiplier used in a low pass filter?

In this article for audioXpress, Bill Reeve helps us to make sense of a misunderstood circuit. A capacitance multiplier is useful as a power supply low-pass filter. It is commonly said that, like Miller capacitance, the capacitor’s value in this circuit is “multiplied” by the transistor gain (β) to lower the filter’s pole frequency.

How is a capacitance multiplier circuit not a voltage regulator?

The effect of placing the transistor in the circuit is that it effectively multiplies the capacitance on the base by the current gain of the transistor, i.e. by β. The capacitance multiplier circuit is not a voltage regulator. The output voltage varies directly with the input Vin as there is no voltage reference.

Why do I omit R2 in a capacitance multiplier?

Simple capacitance multiplier circuits sometimes omit R2 to provide higher output voltage, but this reduces the level of noise suppression provided by this circuit.

Which is the best transistor for a capacitance multiplier?

The first way to build a capacitance multiplier circuit is to use an FET (or MOSFET ). A transistor with higher DC gain (beta value) provides a larger capacitance multiplication factor in a capacitance multiplier circuit, thus BJTs are not normally used in capacitance multipliers as their gain is ~1.

How is the capacitance multiplier used in a peak detector?

This is basically a peak-detector circuit that we use as the supply for the capacitance multiplier. When the voltage over C1 is high enough, D1 will conduct and C4 will be charged. When the voltage over C1 drops, D1 is not conducting, and C4 is used as the charge reservoir supplying power to the capacitance multiplier.