Where is smps used

SMPS Disadvantages Noise: The transient spikes that occur from the switching action on switch mode power supplies are one of the largest problems. The spikes can migrate into all areas of the circuits that the SMPSs power if the spikes are not properly filtered. Additionally the spikes or transients can cause electromagnetic or RF interference which can affect other nearby items of electronic equipment, particularly if they receive radio signals.

External components: While it is possible to design a switch mode regulator using a single integrated circuit, external components are typically required. The most obvious is the reservoir capacitor, but filter components are also needed.

In some designs the series switch element may be incorporated within the integrated circuit, but where any current is consumed, the series switch will be an external component. These components all require space, and add to the cost. Expert design required: It is often possible to put together a switch mode power supply that works.

To ensure that it performs to the required specification can be more difficult. A switch mode PSU uses high-frequency switching 40kHz — 40 thousand or more typically operations a second to transfer power through the transformer.

The high-frequency switching means the same amount of power can be delivered from a much smaller, lighter power supply. This on-off switching and the use of high-performance ferrite transformers also makes the switch mode PSU far more efficient than a traditional linear power supply. At the heart of a traditional linear power supply is a laminated iron transformer. The low frequency of operation means more power must be transferred per mains cycle for any required output.

This means that the transformer must be quite large and heavy. This output will have many variations and the capacitance value of the capacitor should be higher to handle the input fluctuations.

This unregulated dc is given to the central switching section of SMPS. A fast switching device such as a Power transistor or a MOSFET is employed in this section, which switches ON and OFF according to the variations and this output is given to the primary of the transformer present in this section.

The transformer used here are much smaller and lighter ones unlike the ones used for 60 Hz supply. These are much efficient and hence the power conversion ratio is higher.

The output signal from the switching section is again rectified and filtered, to get the required DC voltage. This is a regulated output voltage which is then given to the control circuit, which is a feedback circuit. The final output is obtained after considering the feedback signal.

This unit is the feedback circuit which has many sections. Let us have a clear understanding about this from The following figure. The above figure explains the inner parts of a control unit. Switched-mode power supplies are classified according to the type of input and output voltages. The four major categories are:. The high-frequency voltage pulses from the inverter are fed to the transformer primary winding, and the secondary AC output is rectified and smoothed to produce the required DC voltages.

A feedback circuit monitors the output voltage and instructs the control circuit to adjust the duty cycle to maintain the output at the desired level. There are different circuit configurations known as topologies, each having unique characteristics, advantages and modes of operation, which determines how the input power is transferred to the output.

Most of the commonly used topologies such as flyback, push-pull, half bridge and full bridge, consist of a transformer to provide isolation, voltage scaling, and multiple output voltages. The non-isolated configurations do not have a transformer and the power conversion is provided by the inductive energy transfer.