Power supply circuit plays a crucial role in every electrical and electronic circuit to deliver the power to the owl circuit or other loads such as computers, machines, etc. Different loads have different forms of power requirements at various ranges and characteristics. Thus, the power is converted into the desired form through different power converters.
This happens so that; the different loads work with various types of power supplies like SMPS (switch mode power supply), AC to DC power supply, AC power supply, high voltage power supply, programmable power supply, and uninterruptible power supply.
In such a power source, a high voltage Direct Current power is directly acquired from a similar power source. Eventually, this high voltage DC power is converted usually in a range of 15KHz-5KHz. Then it is fed to a step-down transformer unit of 50Hz. This transformer's output is fed to a rectifier, and this fixed output power is used as a source for loads. The oscillator ON time is controlled and thus forming a closed-loop regulator. The switching-power supply output is regulated using Pulse Width Modulation, and the PWM oscillator drives the switch. This leads to indirect control of the step-down transformer when it is power fed by the transformer. This way, the output remains in control of the pulse width modulation, keeping the output voltage and PWM signal inversely proportional. If the duty cycle is 50 per cent, the max power is transferred through a transformer in such a situation. Upon the duty cycle dropping, the power in the transformer drops simultaneously by decreasing power dissipation.
Such SMPS has an Alternate current input and is converted into Direct Current through rectifier and filter. The resulted, unregulated Direct Current voltage is fed to the power factor correction circuits as it is affected. This is due to the voltage peaks around the rectifier, which draws short current pulses with high-frequency energy that significantly reduces the power factor.
This is something very much similar to the DC to DC converter, but in place of DC power supply, here for the input, Alternate Current is used. So, the mixture of the rectifier and the filter is used to convert the AC to DC, and the switching operation is done through a power MOSFET amplifier. The MOSFET consumes all the low on-resistance and resists high currents.