# Questions tagged [ripple]

Small unwanted residual periodic variation of a direct current (dc) output.

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### Inductor selection for a buck converter with uncertain output current [closed]

I'm struggling to choose the correct value inductor for my design with a TPS54331. Based on my estimations, I calculated a DC current consumption of 1.3 A for my circuit, but sometimes the circuit ...
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### OBD2 Pwr+Gnd causes poor GPS reception in device plugged into it, looking for causes & solutions

Myself and a few others have built a custom device (PCB & components) which is designed to run while plugged into an OBD2 connector in a vehicle and capture GPS location data and transmit it via ...
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### Persistent ripple at the buck converter output

I developed a half-bridge buck converter, I did all the steps, from the converter calculations, such as accommodating the copper in the appropriate ferrite core, wire gauge diameter, etc., my project ...
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### Proof of ripple voltage of capacitor filter?

From Electronic Devices and Circuit Theory by Robert L. Boylestad: To get an equation for ripple voltage, the book wrote, $$\frac{V_{r(p-p)}}{T_1}=\frac{V_m}{\frac{T}{4}}$$ How did they come up with ...
21 views

### TPS61088RHL high ripple noise on normal operation

I have been working with one project which require 12 V power supply with at least 1.5 A current. I used TI Webench power designer tool to create simple 5-10 V input and 12 V 2 A output design. Since ...
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### NCP11187 - SMPS Design Issues

I have been working on a SMPS design using the NCP11187. It should output 24V DC nominal with a maximum ripple of no more than 100mV Pk-PK and be able to output up to 50 Watts. I have generally ...
60 views

### Preventing spikes in inductor current (probably) caused by lab power supply

As part of a university project I'm trying to produce a current through an inductor (610uH), that'll eventually be used as a solenoid. I'm producing this using a PWM voltage produced by a TI GaN ...
1 vote
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### Input capacitance estimation for a buck converter

To estimate minimum input capacitance required for a buck converter to help with power stability & noise suppression, I came across below equation by TI. https://www.ti.com/lit/an/slyt670/slyt670....
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1 vote
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### Voltage transients in stepper driver

I am having considerable amplitude of voltage transients in my ~60V stepper driver design. I referenced High-Voltage Stepper Reference Design Using DRV8711 document for building the circuit albeit ...
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### Inductor magnetic field collapses during switching?

SEE EDITS BELOW I'm running into some problems with my Buck converter design. During the switching period the inductors magnetic field seems to collapse, which generates some large voltage peaks. That'...
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### Switching power supply has high ripple voltage no matter how many capacitors are added

I'm designing a board that uses a Texas Instruments TLV62569DBVR (datasheet here) to convert 5V input from a USB power supply to 3.3 volts to be used to power an ESP32-WROOM-32D-N4. I am having lots ...
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### LC Filter Creates Ripple Voltage in Buck Converter

I'm currently designing a synchronous buck converter and trying to simulate it in LTSpice. I know the purpose of L1 and C4 is to act as a filter to smooth out the output, since it would be rapidly ...
1 vote
190 views

### Buck converter has low frequency ripple with high amplitude

I "designed" a simple buck converter, which is basically a clone of the 5V reference design in the TPS6293x datasheet. The converter is outputting the correct voltage on average, but has ...
1 vote
147 views

### Can you power 2 voltage rails simultaneously using a buck-boost converter?

I am designing a custom PCB and want to power 2 rails: a 3.3V and 5V rail, with a single 250mAh LiPo battery (3.7V) and need the 5V rail to have as stable a voltage as possible. I understand that a ...
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### Choosing filter capacitor and inductor for AC to DC rectifier

I am designing a three phase AC to DC rectifier. This DC output will be connected to a 6 IGBT bridge. That IGBT will be controlled using SVPWM technique to control a PMSM motor. What factors do I need ...
740 views

### How much charging ripple voltage is allowed while charging a LiFePO4 battery?

We are designing a buck controller to charge a LiFePO4 battery (4 series 9 parallel cells, each of 3.2 V). Hence, we would like to charge the battery pack with 13.90 V but the buck output has got a ...
52 views

### Ripple Noise Using Capture CIS and PSpice

I am trying to measure the ripple output noise of a regulator using simulation on Orcad CIS and PSpice. The output voltage and current are correct however the transient time response is not showing ...
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1 vote
321 views

### How to use measured values to obtain an experimental ripple factor for a full wave bridge rectifier with no filter

Hello this is my first post. This is my thought process: I can use the following equations to calculate the theoretical ripple factor for a full wave rectifier: Through simplifying, it can be ...
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1 vote
58 views

### What result does digital multimeter show when measuring filtered AC V? Is it Vavg or Vrms of the ripple voltage? What's the formula to calculate? [closed]

Can somebody tell me what result does multimeter show when measuring filtered AC V? Is it V avg or V rms of the voltage ripple? And what's the formulas to calculate this?
73 views

### low frequency ripple current RMS amps and temperature rise in MLCC

Manufacturers only specify this metric of 0.1, 0.5 and 1MHz. Is there any way to calculate / estimate the temperature rise in these capacitors for much lower frequencies, in the Hz range, based on ...
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1 vote
730 views

### Flyback converter design using UC3843

I am designing a offline power supply which will 24 V as output with 2.5 A. I found UC3843 as better option. I used TI we bench tool to design my power supply. This is the schematic I got from it. The ...
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361 views

### Understanding ripple in oscilloscope

I have a linear (non-switched) power supply that states in the specs a ripple of 10 mV p-p Measuring it with the oscilloscope, as you can see in the image it measures Vpp = 30mV. The oscilloscope is ...
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1 vote
221 views

### Removing peaks (noise) in the output of Switch Mode Power Supply

simulate this circuit – Schematic created using CircuitLab I have a 220/24V SMPS, which I use to power 2 buck convertors in chain. First one 24-12V, and the second one 12-5V. With this setup I ...
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1 vote
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### DC bus capacitance design for SPWM inverter

I am working on a 5kW grid-connected inverter where I need to find the DC bus capacitance value. I understand that the capacitor serves 2 purposes: 1) to provide a low impedance path for the high ...
1 vote
35 views

### Large Ripple on Synchronous Boost Converter

I was working on the synchronous boost converter simulation with the following schematic, with SUP70101EL (P-channel MOSFET) and IRFB4310Z (N-channel MOSFET). I don't understand why the output voltage ...
276 views

### ZVS circuit to generate high DC voltage

I'm trying to design a high DC voltage generator to create a voltage differential between the upper and the lower part of a cloud chamber I'm building. I'm trying to use a ZVS circuit to amplify an ...
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### Bridge rectifier circuit with a step-up transformer

I have been experimenting with a full-wave bridge rectifier in LTspice. I am trying to step up 120 V AC/60 Hz to 1 kV DC for a load of around 2 kΩ. The step-up transformer has a ratio of 25:9. The ...
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### Does the position of capacitors create ripple voltage?

I'm designing a multi-sensor board controlled by an ESP32-Pico-D4. I did tests with version 3 being able to programm it, but I decided to make it smaller by removing the USB chip (just leave pins for ...
407 views

### How to remove 200 mV ripple from my power supply? [closed]

I am using a step-down-converter to get a variable supply output in the range of 2-4 V from a 5 V input voltage from an adapter. The problem I am facing is that I get a 200 mV ripple which looks like ...
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### Selecting a capacitor / ripple current / ESR

I have a small control with a linear power supply, bridge rectifier, and smoothing capacitor. It turns on a motor for just 10 seconds or less and in the worst case only every 3 minutes, but maybe much ...
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### Ripple rejection of capacitance multiplier when compared to linear regulators

There are some posts and discussions how a circuit popularly called a “capacitance multiplier” could reduce low frequency ripple noise (at 50/60 Hz or 100/120 Hz) and could perform better than common (...
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1 vote
170 views

### How to minimize the ripple on a buck regulator powering a CM4?

While designing a Raspberry Pi CM4 application board, I found an issue with the power supply. I selected the same IC as the official CM4 I/O board: the AP64501SP-13. I used even the same values for a ...
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### Limits to number of parallel smoothing capacitors in a power supply

Would there be any disadvantage (other than a high component count) to using seven 470 μF, 16 V electrolytic capacitors instead of one 3300 μF, 16 V capacitor to smooth power supply ripple?
84 views

### Why do I have to connect ground to earth for my board to work?

I built a 3d printer myself, Im using an off the shelf controller board with a 24v 400w led power supply that I found for cheap on AliExpress. The quality of the power supply is far from perfect,It ...
62 views

### Why do I get a different value for DC output?

I am given the circuit shown below, a full wave rectifier with a filter. To find the DC output on a full wave rectifier with a filter, I was given the formula: V_{dc}(out) = \frac{V_{M}}{1+\frac{1}{...
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The converter works in the inverter mode and gives an output of -5V. I present a diagram based on the documentation. I want to eliminate the output voltage ripple with a ferrite bead. Unfortunately, I ...
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### Ripple problem when using a type III Compensator for buck boost converter

I need your help, and from my last question here, I understand I need a closed-loop for my design, which helps to reduce the output overshooting. Below is the plot. From the plot you can see my ...
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### Does voltage ripple matter to a relay driven by a transformer?

If you have a relay that accepts actuation voltages of between 9-25V does it matter if you have a relatively large amount of ripple on that line? I ask because my design steps down 230V-15V with a ...
167 views

### Very high ripple at the output of my converter

I need help on how to reduce this ripple at the output of my converter. I already have a 1uF x8 capacitor at the output, butI am still getting loads of noise. Can you help with the best method to have ...
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### Strange simulation result: Can a rectifier diode conduct when the output terminal is open?

How does the output voltage build up for the below circuit when the terminal is open? Does LTSPICE assume any default node capacitance which gets charged- Not sure what causes the discharge/ripple in ...
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### Ripple voltage filtering capacitor

I'm an self-taught high schooler who's trying to understand how filtering capacitors work. I've searched and read multiple websites trying to understand how filtering works. At the point where I am, I'...
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### Is there a relationship between capacitor ripple current and the transformer secondary current output rating?

As an example: I was looking at a 10000 μF, 50 V capacitor with a ripple current rating of around 5 A at 20-120 Hz. My transformer secondary is rated for 24 VAC, 20 A.
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### Capacitive Signature on CAN Bus Driver SN65VHD230

I'm working on a small custom PCB that uses the TI SN65VHD230 CAN Transceiver and the square waveforms of the CAN bus aren't as clean and crisp as it seems they should be. I have a 10 μF MLCC on the ...
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### Voltage ripple driving class D amplifier

I am learning to use I2S/PCM to drive speakers with the ESP32-C3-WROOM-02-N4, and I am using an IC to accomplish the DAC and amplification. The IC is the Adafruit I2S 3W Class D Amplifier Breakout - ...
161 views

### DC-DC buck converter inrush start on voltage

I started to examine the behavior of the converters on my custom board. The input to the converter comes from an external supply with a voltage of 20 V, the required output voltage is ~12 V. When I ...
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### Transfer function of two frequency spectra

When you have two amplitude frequency spectra (fourier spectrum), in this case of a torque ripple, how do you define the transfer function (or the ratio) between both? How do you "divide" ...
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### Why is an inductor rather than a capacitor used to smooth switch mode regulators

I understand (at least at a high level) how to use both capacitors and inductors to reduce noise but I don't understand the advantages/disadvantages of each approach or why one is chosen over the ...
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### Small-Ripple Approximation In Buck Converter Analysis

In almost all DC-DC converter books, they introduce the small-ripple approximation to make the derivation of the the Vout-Vin relationship easy. Usually, they assume that the output of the converter ...