Page 98 - CITS - Electronic Mechanic - TT - 2024

ELECTRONICS MECHANIC - CITS

To guarantee a constant output stream of the intended voltage, the control circuitry continuously monitors the
generated voltage and modifies the high-frequency switch.
AC-DC Converter SMPS Working
The input supply in this sort of SMPS is AC, and the output is DC. This AC power is converted to DC using
rectifiers and filters. This erratic DC voltage is applied to the impacted circuits for power factor correction. This is
due to a low current pulse that occurs near the voltage peak inside the rectifier.
DC-DC Converter SMPS Working
This power source’s input supply comes straight from a DC power source, which provides high-voltage DC
power. Next, the frequency of this high-voltage DC power supply is lowered to 15KHz–5KHz. A 50 Hz steps-down
transformer unit receives it after that. This transformer’s output serves as the rectifier’s input, and the rectifier’s
output provides the power that loads are drawn from. A closed-loop regulation is created when the oscillator is
regulated on time. The transformer transfers its maximum power when its duty cycle is 50%. If its duty cycle is
lowered, the transformer’s power is likewise decreased by lowering the interruption.
Fly-Back Converter Type SMPS Working
A fly-back converters SMPS is any SMPS with an output power of less than 100W. The circuit for these SMPS is
easy to understand and less complicated than that of other SMPS. Low power consumption is the purpose of this
kind of SMPS. Using a MOSFET, the unregulated voltage that is input of constant intensity switches at a frequency
of about 100 kHz to the desired output voltage. A transformer is used to achieve voltage separation. A workable
fly-back converter can be operated while the switch is controlled via PWM. Unlike a typical transformer, the fly-
back transformer exhibits unique qualities. The two windings that make up the fly-back transformer function as
magnetically coupled inductors. To improve filtering, capacitors and diodes are used to spread the transformer’s
output.
Forward Converter Type SMPS Working
This kind of SMPS shares nearly the same design as the SMS flyback converter type. In order to control such
SMPS, the switch is linked to the secondary winding that powers the transformer’s output. The circuitry for filtering
and correction is more intricate than that of a flyback converter. These SMPS, commonly referred to as DC-DC
buck converters, are employed in transformer isolation and scaling applications.
Types of SMPS
For end users, these are some of the most well-known and widely utilized Switched Mode Power Supplies.
DC-DC Conversion

High-voltage DC power that is received from the AC mains has been rectified and filtered. After that, the high DC
voltage is switched and sent to the primary side step-down transformer. The rectified & filtered output is gathered
at the step-down transformer’s secondary side before being supplied as the output into the power supply.

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CITS : E & H - Electronics Mechanic - Lesson 48 - 55