Questions tagged [power-dissipation]

Anything related to power dissipation in electrical and electronic circuits and components, i.e. the process in which electrical energy is converted to heat when current flows through them.

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97 views

How to be sure that a ceramic capacitor can manage a RMS current?

I'm in the middle of a design and I need a capacitor of: 10µF Rated at 10V Has to handle a ripple current of 250mA RMS, at 400kHz Most electrolytic capacitor data sheets give a maximum RMS value for ...
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1answer
20 views

How can I determine PD for given impulse, based on transient thermal impedance for BJT?

I have (selected) a BJT to work with rectified mains application. Transistor is PBHV9560Z (600 V, 0.5 A PNP) https://assets.nexperia.com/documents/data-sheet/PBHV9560Z.pdf Under normal operation ...
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0answers
10 views

Can Quartus help the user find out power saving if one uses clock control block to disable clock?

The clock control block can be used to disable clock to a section of the design thereby achieving clock gating. Can Quartus help the user find out how much saving such a measure will help achieve in ...
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1answer
59 views

Power dissipation calculation for FPGA-ADC interface

An FPGA can be interfaced with an ADC using CMOS or LVDS. Is there a way to use simulation to predict the power dissipation of the I/O blocks for a given operating frequency for this interface? If so, ...
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35 views

Maximal power dissipation of the resistances in this circuit

Assuming I have this circuit below with : Ic = 200mA , β = 100 , UCE = 15 V So with some calculations : Ib = 2mA , R1 = 4k7 Ohm , R2 = 75 Ohm If I want to calculate the power dissipation of both URV1 ...
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39 views

How can FPGA differential signal use lower power when it has two lines instead of one?

I am a bit confused about differential signaling on FPGAs. I am trying to figure out how does power dissipation in FPGA differential signaling compare with power dissipation in FPGA single ended ...
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1answer
66 views

Can I choose a heatsink based on its thermal design power (TDP) for cooling LED chips?

I am confused about TDP ratings and what they refer to actually. The reason I am confused is because most modern CPUs and GPUs, although not ideal, are able to sustain very high temperatures (80 C or ...
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44 views

Power input connector for power distribution board

I have been looking at several different power distribution module designs and the all seems to use a large bolt for the main power input. I am curious what these connectors are called and how they ...
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1answer
60 views

Power dissipated between two points

In the follwing, if the power dissipated between a and b is 210 watts, what is the value of Vb?
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1answer
50 views

How does complex loading affect an op amp's power dissipation

I'm trying to calculate power dissipation in a complex load. I know that the power loss due to the resistive component is dissipated, and that the power loss due to the reactive component is canceled ...
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1answer
39 views

TTL Gates Power Dissipation Values

I am not finding any datasheets that provide clear information about the power dissipation of some gates of the 74LS series: 08, 02, 04, 00, 32 and 86. Can someone help?
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1answer
60 views

Reduce DC power supply for battery charging

I have a DC power supply from either a WIFI router or printer (not sure) rated for 13.5V @ 1.2A output. This is a replacement charger for an electric ride on car as it was originally 6V and I've ...
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1answer
69 views

Comparing power consumption of different FPGAs

I want to compare power dissipation of FPGAs from different vendors, the I/O count and the logic resource shall be matched as close as possible when choosing the FPGAs. I want to create a trivial ...
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2answers
61 views

Lower duty cycle less efficient?

Assume you have a DC voltage V, ideal switch (no switching losses) operating at some frequency f and duty cycle ...
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1answer
86 views

Over voltage protection IC keeps burning

I am currently working on a project where over voltage protection is necessary. I made a test circuit using an LP5300 (SOT23-6 type.) https://datasheet.lcsc.com/szlcsc/1912111437_LOWPOWER-...
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1answer
70 views

Mosfet Thermal Resistance calculation

I went through the application notes of infineon and TI. In the datasheet on the MOSFET, there is a junction to case Thermal Resistance given. Can we use these values to calculate the power ...
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0answers
35 views

P-MOSFET power dissipation spike when turning off (10 - 100khz)

I designing battery charging circuit, I found the following step down converter for charging. The target is to charge a battery with 3-4 A, but the P-FET (NTF2955) becomes very hot at 0.5 amps: I ...
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2answers
49 views

Finding the power dissipation in a wye-connection given resistors

The problem that I'm attempting to solve is the following: Three 1000 Ω resistors are connected in Y to a 200-Vac line. The power dissipation of the Y combination would be _____W. a. 42 b. 41 c. 40 d....
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59 views

Why do I get such high values when calculating the power dissipation of MOSFET in boost-converter circuit?

I'm a hobbist interested in electronics so I don't have any "professional" training on that. Currently I'm trying to design a boost converter and now I'm stuck at some calculations. I wonder ...
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2answers
195 views

Calculate voltage drop across Linear MOSFET in saturation region

Considering the below schematic, how is the voltage drop across the MOSFET calculated when it is operated in the saturation region? I am trying to calculate the power dissipated by the MOSFET so that ...
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2answers
40 views

Can I exceed the 120mA per channel on the TLC5940 if I use external resistors in series with LEDs?

Datasheet The TLC5940 drives 16 channels of LEDs at constant current using PWM. I assume the 120mA limitation per channel as described in the datasheet has to do with how much power the HTSSOP ...
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1answer
34 views

Am I calculating my shunt FET power dissipation correctly?

simulate this circuit – Schematic created using CircuitLab I'm designing an LED driver circuit that requires very fast PWM switching at a high resolution (10bit at 30khz requiring a minimum ...
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2answers
66 views

High thermal load PCB for short duration

I got 30 buck converters on 4 layer pcb (70x130mm). Each will dissipate ~2W for typically 30 seconds followed by a very long break >10min, and I'm worried about overheating. Although it is not a ...
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2answers
27 views

overloading rated current capability of a connector

If each connetion of a screw terminal (the one in question in the picture) is rated for 3A at 380V, is it probably safe to use each one for 12A at 12V? Is there a way to work this out? Thanks
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62 views

LM337 regulator not warm

I built this circuit and am getting correct voltages except the negative regulator (lm337) is cool to the touch whereas the positive regulator (lm317) is very warm. Why?
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1answer
42 views

Reconciling power dissipation and output characteristic of BJT

From the datasheet of 2SC1384 I got the following characteristics. I plan to use this transistor in an RF amplifier. The power dissipation characteristic sets a limit on the dissipated power of the ...
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1answer
74 views

How to provide a 5 volt rail from 24 volt source

Edit: Added practical observations at bottom. I need to provide power to an ESP8266 12E NodeMCU board, and my "raw" power is a 24 volt "wall-wart" PSU. My first thought was just to use a 7805 with a ...
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1answer
69 views

Power dissipation of TLC6C5712-Q1 LED Driver IC

I am using this TI LED Driver IC to drive 9 LEDs I want to calculate the Power Dissipation of the Resistor (20k 1% 0402) which I have connected to the IREF pin. To calculate the power dissipation of ...
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189 views

Verifying maximum switching frequency calculation of a hard switching IGBT

I have recently been working on a power H-Bridge meant to drive an inductive load in hard switching mode. I calculated the maximum operating frequency limitation due to maximum power dissipation of ...
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1answer
105 views

Power dissipated in resistor

I have the following problem: Consider the graph below What is the power dissipation in a 75 \$\Omega\$, when the voltage across it is the plotted voltage above? Okay, so my idea was to split the ...
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2answers
55 views

Given the surface area, volume, and temperature of an IC, can you calculate how much power is dissipated?

Assume the temperature of the IC is uniform and constant and the surface area and volume are known. Can you calculate from these values the power dissipated by the IC through heat? If not, what ...
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53 views

Power dissipation BJT transistor as voltage follower

Following the discussion from this thread I am finalizing my calculations. I am not sure that I am calculating the power dissipation correctly. Given the following circuit I need to operate the opamp ...
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2answers
461 views

Diode selection for step-down Converter

I have built quite some buck converters for ~3A@3-5V (~1MHz, 24V Input) and I always used schottky diodes due to their low forward voltage drop (and therefore low power dissipation during free ...
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1answer
47 views

SPICE IC model in-circuit power dissipation

I'm looking into a way to calculate the power dissipation of any arbitrary IC in circuit on SPICE. I eventually hope to create simple scripts that can list power dissipation of the device and ...
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4answers
686 views

Heat Dissipation Calculation for MOSFET

My challenge at the moment is dissipating 60A of load current through an array of MOSFETs. Here are my specs: No cooling fans Heatsinks allowed, if needed FET and/or heatsink cannot attach to the ...
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2answers
85 views

Possibility of dissipating 20 W via Nichrome wire safely

I am looking to use 1 foot (0.3 meters) of 32 AWG nichrome wire to dissipate roughly 20 watts of power. Assuming the wire was submersed in still transformer oil, would I be able to do this without ...
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1answer
44 views

Advice on a voltage measuring circuit

I've been working on a voltage divider circuit that will hopefully allow me to measure voltages between 0-60 kV DC (80 W) as 0-889 volts DC. The voltage divider section that is used to measure the ...
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1answer
213 views

Calculation of Power Dissipation of Memory ICs and Microcontrollers

Can someone tell me how to calculate the power dissipation of digital ICs like Nand Flash, QSPI NOR Flash and Microcontrollers? For Microcontrollers, we can get the power dissipation for GPIO like, ...
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1answer
349 views

Should thermal pads be connected to GND or not?

I'm creating a footprint for the TPS2141 (LDO and current limiter) and I wonder if the thermal pad should be connected to the GND plane or if thats a bad idea? Should it just have its own copper zone ...
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1answer
101 views

Calculating Power Dissipation in a Filter

Apologies in advance if my question seems too basic. I don't really know where to go from here. I understand that power can be calculated as P = IV or P = V^2/R or P = I^2 x R. I think I'm not ...
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1answer
452 views

Quiescent current vs GND pin current for Linear Regulator IC power dissipation

I want to confirm that, for a linear regulator IC, quiescent current multiplied by the input voltage accounts for the IC power dissipation(including drop-out voltage loss). I ask because the ...
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3answers
3k views

Heatsink on underside of PCB

I have prototyped some DC-DC converter modules, and they work well. However due to size, I don't have a huge amount of copper pour for them to dissipate their heat. I have used 2oz copper but the ...
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5answers
1k views

Transistor power dissipation rating

I'm trying to build the following circuit Except mine is a 24V ~20A (500W) motor, so I need to swap the components. I'm currently looking into transistors and I've stopped on the 2N6284 (NPN) ...
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1answer
325 views

Triac power dissipation

I'm driving a high power load with the BTA440Z (datasheet): line voltage is Vac = 230 AC, load power is P = 1.33 kW, thus load current is ~ I = 5.8 A. If i swap the load with another ...
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1answer
175 views

Thermal resistance Junction - Maximum Power dissipation

I want to understand the real meaning of the parameter 'Thermal Resistance Junction to Air (°C/W) to calculate the power dissipation. So for example if the value of this parameter is 250°C/W, should I ...
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2answers
132 views

POWER MOSFET - Thermal Design

i have some doubts about with this thermal design? first, the calculations and infos: My load (a motor) uses an average current of 7A, I could not measure the current peak at the beginning of the ...
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0answers
131 views

ESD Diode - clamping voltage

I'm trying to replace an existing ESD diode(PESD1CAN) in my application CAN circuitry due to some reasons, I've found an alternative ESD diode(RSB27C2), but compared to the diode that I already have ...
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2answers
3k views

LM317 - Calculate dissipation due to voltage drop

If I use a linear voltage regulator as LM317: Input voltage = 24 V Output voltage = 5 V (so a voltage drop of 19 V) Mean load = 480 mA (peak load = 700 mA) From the datasheet, I read that maximum ...
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1answer
2k views

How much power does LM7805 dissipate?

I'm using an LM7805 in voltage regulator mode. Vin is 15V Vout is 5V (regulated) The attached load draws 200mA How to calculate how much power the LM7805 would dissipate in this setup (and whether ...
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1answer
61 views

How do I treat this “lamp” to find power dissipated?

This is my circuit. I need to find the power dissipated by Vlamp. So the lamp turns on if the Vlamp is more than 2V. When the ...