What causes AC ripple?
Ripple (specifically ripple voltage) in electronics is the residual periodic variation of the DC voltage within a power supply which has been derived from an alternating current (AC) source. This ripple is due to incomplete suppression of the alternating waveform after rectification.
What is ripple voltage of voltage regulator?
Ripple voltage means the amount of AC voltage that appears on a DC voltage. The main reason for the ripple voltage is that the converter converts the AC voltage into a DC voltage, but the AC voltage cannot completely eliminate. The ripple voltage shown in Figure 1 is low frequency ripple voltage.
How does a low dropout linear regulator work?
In portable communications, low-dropout linear regulators (LDOs) generate supply voltages for the RF circuitry that must be especially clean when powering the synthesizer and voltage-controlled oscillator (VCO). The supply that powers the regulator often includes wideband AC ripple superimposed on the DC.
What is the power supply ripple rejection ratio?
Power supply ripple rejection ratio (PSRR) is a measure of how well a circuit rejects ripple coming from the input power supply at various frequencies and is very critical in many RF and wireless applications. In the case of an LDO, it is a measure of the output ripple compared to the input ripple over a wide frequency range (10 Hz to 10 MHz is
What does line regulation mean in power supply?
In practice, line regulation refers to the regulator output voltage in terms of %/V OUT. This is particularly useful when the same regulator is available with numerous output-voltage trim options.
What is the penalty for using two linear regulators?
Using two linear regulators in series doubles the PSRR at any given frequency (assuming identical regulators). The “penalty” for this approach is the doubling of the dropout voltage and the need for an additional capacitor. A good design choice is to share the voltage drop across each regulator.