Ripple is 50hz or 60hz?

[danny davis]

The ripples frequency is either 50hz or 60hz?

Ripple on a full wave rectified supply is 2x the mains frequency

Full wave rectified supply 60hz X 2 = ripple frequency is 120hz?

 

[IanP]

The ripples frequency is either 50hz or 60hz?

Ripple on a full wave rectified supply is 2x the mains frequency

Full wave rectified supply 60hz X 2 = ripple frequency is 120hz?

For 60Hz after full wave rectifier it is 120Hz ...
For 50Hz .....................100Hz ...
:wink:
IanP

 

[ashugtiwari]

consider line frequency to be 50Hz, when u apply full wave rectification, the o/p is half sine positive side ripples which is periodic in nature and at frequency 100Hz i.e. 50x2.
Considering the o/p of rectifier just contains one single big capacitor, the o/p will have the same 100Hz ripples.

now, if u r using SMPS or any switching regulator, the o/p ripple frequency is generally the charging discharging rate of inductor/capacitor of convertor, which is approximately equal to PWM frequency.

Hope that helps.

 

[danny davis]

So whats the ripple frequency for Switching powers supplies and PWM power supplies?

What does SMPS mean?

 

[karthickb3e]

Please refer your country supply frequency.. for example INDIA - Supply frequency is 50Hz... from that reference you conclude for frequency cakculation...


SMPS means Switched Mode Power Supply... Search in Google for More Details

 

[danny davis]

USA is 60hz

whats the ripple frequency for Switching powers supplies?

 

[danny davis]

switching power supplies ripple is 20Khz to 500khz?

 

[IanP]

switching power supplies ripple is 20Khz to 500khz?

In SMPS(s) the ripple is exactly at the switching frequency, see attached picture ..
So, depending on a particular unit, the ripple can occur at, say, 36kHz or in another application at 1.1MHz.

:wink:
IanP

 

[danny davis]

the ripple is exactly at the switching frequency

I'm not sure how Switching power supplies work

What is the switching frequency circuit do?

 

[elecbaba]

https://en.wikipedia.org/wiki/Switched-mode_power_supply

 

[danny davis]

When troubleshooting Switching power supplies, what is the very common problems that happen?

I heard it's hard to troubleshooting switching power supplies, is this true?

 

[elecbaba]

what is the very common problems that happen?

Its power swithes, rectifier diodes and pcb burns into fireworks and you don't get the original schematic. If you learn general theory, you may become a guru with experience.

 

[ashugtiwari]

in short as far as i know
1. There are 2 types of voltage regulators, linear and switching.
2. linear regulators simply regulate voltage to requires o/p levels and remaining energy it dessipates, hence the efficiency is very low and this regulator used seldom in some testing only applications.
3. switching regulator takes DC input and generates square wave o/p, so the average voltage of that wave is o/p voltage and current which is required, remaining energy is just returned back to generator, hence very high efficiency. Change in the frequency of square wave changes o/p current and change in duty cycle changes o/p voltage.
4. for this a switch and energy storing element like L or C is used.
5. 3 types of switching regulators: buck, boost, buck-boost or flyback
6. buck - o/p voltage less than i/p, boost-o/p voltage greater than i/p, flyback-o/p voltage is inverse of i/p i.e. if i/p is +5, o/p can be -5 or any other negative voltage.
7. SMPS is switch mode power supply which is buck switching regulators with very high o/p current and different voltage o/ps.

do some googling to find more info on switching regulators.
hope that helps.

 

[danny davis]

A Switching Power supply adjusts the Pulse width to do output voltage regulation? how does this work?

I'm not sure how the Pulse Width works to adjust the output voltage regulation in a switch power supply

The ripple frequency is from 10K to 25K?

Since the ripple frequency is from 10K to 25K a small filter cap is used? 1uf cap

You don't have to use big filter caps like in a linear power supply

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To get the turn ratio of a power supply

The formula is the transformers secondary voltage and divided by the primary's voltage = turn ratio

Secondary voltage is 25 volts
Primary voltage is 150 volts

25 divided by 150 = 6

Turn ratio is = 1 to 6?

 

[danny davis]

A switching power supply has a stage where is converts DC into an High frequency pulse

Is this Stage/section that does this called an inverter or switcher?

How does it Convert DC into a high frequency Pulse?

The high frequency pulse is at what frequency range mostly? and does it have a Ripple frequency also riding on top of the pulse?

 

[ashugtiwari]

any periodic wave (not sure if same applies to aperiodic) has two different values called Vavg which is nothing but average of all instantaneous voltagesin one period i.e. average voltage and Vrms, this tells the energy available in signal i.e. power of signal.
if u filter the asymmetric PWM wave with 50% duty cycle, the o/p cap will contain ripple freq of PWM freq. the mean value of this ripple is o/p voltage in switching regulator.
capacitor and inductor selection depends on ripple freq, o/p current, transient response etc.
u can do loop analysis and find all equations for buck or boost convertor and then select appropriate component values or see on online detailed text on google on switching regulators.

hope that helps.

 

[danny davis]

What are these switching power supply waveform's called please?

 

[goldsmith]

What are these switching power supply waveform's called please?

switching-power-supply-waveform-1.jpg
switching-power-supply-waveform-2.jpg
switching-power-supply-waveform-3.jpg
switching-power-supply-waveform-4.jpgswitching-power-supply-waveform-5.jpg

Hi Danny
However it would be better that you create a new thread for this question but those waveforms consist overshoots and ringings . it depends on what kind of switching circuit they are related to and where those waveforms are coming from .
Best Wishes
Goldsmith

 

[danny davis]

Here is the circuit







I'm not sure what those IC chips do, can you explain what is going on in this circuit

There is two diodes D117, D119 that are feedback to change the PWM modulation signal to the U113 chip to regulate the output so the output is regulated

I'm not sure how this work

 

[ashugtiwari]

i can't open the images, so whatever i understood from thumbnail, trying to give answer which is very vague:
1. The waveforms are transient response of switching regulator o/p i.e. circuit made up of inductor, diode, capacitor.
2. The circuit o/p is damped sine wave at freq which is resonant freq of L & C. Increasing L or C will decrease damping.
3. The ckt is SMPS with one PWM generator and o/p is taken through switching transformer.

hope that helps.

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i can't open the images, so whatever i understood from thumbnail, trying to give answer which is very vague:
1. The waveforms are transient response of switching regulator o/p i.e. circuit made up of inductor, diode, capacitor.
2. The circuit o/p is damped sine wave at freq which is resonant freq of L & C. Increasing L or C will decrease damping.
3. The ckt is SMPS with one PWM generator and o/p is taken through switching transformer.

hope that helps.