Switching power supply is a high-efficiency power supply, widely used in electronic equipment, its big advantage is that the input voltage can be converted into a stable DC output voltage.
But the output voltage of the switching power supply will also appear some ripples, these ripples will affect the normal operation of the electronic equipment and reduce the life of the equipment, so the need to eliminate the ripple of the switching power supply.
Causes of ripple in switching power supply
The ripple in the output voltage of the switching power supply is mainly caused by the switching of the switching device.
When the switching device is turned off, the energy in the input capacitor is released into the load capacitor, resulting in a ripple in the output voltage. Moreover, there are useful signals and noise signals in the output voltage of the switching power supply, so measures need to be taken to eliminate these ripples.
What are the common methods to eliminate ripple in switching power supplies?
At present, there are three commonly used methods to eliminate the ripple of switching power supply:
One is achieved by the filter, the second is achieved by the calculator component, and the third is achieved by the reverse voltage circuit.
1. Achieved by the filter
The first way to achieve this through filters is to filter the output voltage to eliminate noise in the output voltage. The type of filter varies according to the frequency range that needs to be filtered.
What type of filter is used in power supply?
There are three common filters: low-pass filter, band-pass filter and band-stop filter.
Among them, the low-pass filter is the most commonly used one, which can weaken the high-frequency component of the voltage.
In switching power supply, inductors and capacitors are generally used to form LC low-pass filters. The LC filter composed of inductor and capacitor in parallel can effectively absorb the high frequency component of voltage and filter out the ripple.
In addition, in order to improve the performance of LC filters, some power supplies also use a multistage filtering method, which can more effectively reduce the ripple in the voltage.
2. Achieved by the calculator component
The second way to achieve this through a calculator component is to use a calculator component to reduce the ripple in the output voltage.
A gate level calculator can add two signals that vary in frequency and then output a smooth signal. Therefore, after adding an entry-level computer to the output voltage of the switching power supply, some fluctuations can be eliminated through its capacitance effect.
3. Achieved by the reverse voltage circuit
The third way to achieve through the back voltage circuit is to use the back voltage circuit composed of the reverse series capacitor and resistor to eliminate the ripple of the output voltage of the switching power supply.
The backvoltage circuit capacitor can make the analog signal disappear when the AC signal cycle is half up and half down, thus eliminating the power ripple.
While resistors can avoid fast discharge of the back voltage circuit capacitor filled, and improve the performance of the back voltage circuit.
To sum up
The methods to eliminate the ripple of switching power supply mainly include filters, computer components and back voltage circuits.
In practical applications, it is necessary to choose the appropriate method to eliminate the ripple in the switching power supply according to the specific situation, so as to ensure the normal operation of the electronic equipment and extend the service life of the equipment.