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27 Threads found on edaboard.com: Switching Power Supply With 7805
Is there anyone experienced with 7805, which input is supplied by switching power supply ? I use +12 V from regular PC power supply. Just now, it went broken. Is it wrong to use switching PS for 7805 input ?
hello i have 2.4GHz Video PAL & audio RF modules 16 dB. RX and TX. need 5V. how can i supply it? is it necessary to feed them with a linear supply ? 7805 heats so much. can we supply it with a switching power supply? (and which is (...)
o....LM2596. I just been known that such high switching power supply IC, also with adjustable voltage. It seems very good!! Remark: for LDO ic, one could LM1117, or try something like that on Torex.
Everything's fine with the schematic. Obviously, this circuit is used for a synchronization purpose. Pin5 should be connected to +5V (or the positive rail) by a pull-up resistor. The "60Hz" labeled rail, in this case should be considered as an output rail. On that same rail, if observed with scope, the signal should be rectangular with (...)
Yes obviously if your motors are drawing 500mA at 5V, then total they will be drawing 2A.If you are not selecting a proper current rating linear regulator then output voltage will drop i.e less than 5V. You can't use an 1A transformer.You have to use 3A transformer or higher for LM350. Also you can use LM2576 switching regulator IC to make your
When Vout=4.3V measure the Vin (so you can understand if the 7805 is working correctly), and measure also the current consumption of the board. Remember that a 7805 really sourcing 1.5A could be very hot !! :twisted: with few components (e.c. 1 controller lm259x from NatSemi, 1diode, 1 inductor and some capacitors) you can realize a (...)
I managed to reduce such noises with switching regulators like LM2574 . The LM2574 contains all of the active circuitry necessary to construct a stepdown (buck) switching regulator and requires a minimum of external components.
Hi ! You did not inform what are the currents required. The 7805 will become hot only if the current is high, for low currents a heatsink attached to it could be the solution (and cheapest). I suggest you to use a LM2976-5.0 switching regulator, with the 18Vdc input and regulating to 5Vdc on the output. You need only as additional (...)
I am not allowed to use a prebuit regulator and must therefore construct one myself. I don't think the answer use a "regulator IC" like LM317, L8205, or LM2576 makes sense as a response to this post. timy, what Ianp suggests is a good answer for a realitively wide range (limited by the series transistor) of load currents.
Well to tell you the truth I dont have any circuit diagrams. I just opened the box and figured it out. Well yeah SMPS is THE thing for a DC power supply. PS: If you find any circuit diagrams then do share it with me. SMPS use the DC-DC converter concept. For example TPS51020 Buck Controller IC can be used to make a
Use a big enough heatsink, 7805 has a thermal protection and is shut down when the temperature is to high. For bigger current you may use an external transistor. The best solution to minimize power dissipation is a switching regulator like this: www.national
i saw in the switching power supply . they always put big L and c to supply the current during curve down.. and make it constance. bigger L with bigger current.. during peak output..
A switching regulator would probably be suited in your case to have better efficiency and low heat on the regulator. A solution like would work fine. Alex ---------- Post added at 00:44 ---------- Previous post was at 00:38 ---------- You can also use 78T05 whic
for level translator yo can use the mosfet solution shown 5V-3.3V bidirectional level converter ? rocketnumbernine d.holmes > hardware > simple bus level-shift For the 4v power supply you will probably n
I don't think there is any fault, depending on the voltage drop across the regulator and the current it provides you will have a power los as heat, the higher the input and the higher the current the more heat you are going to get. Maybe you can try a switching regulator.
if its only for testing, use the power supply from an old PC (+ and -12, + and -5) regards magnus PC power supplies are switching devices, won't even start with a 30 mA load.
I changed IRF9540 by L298 and this circuit worked correctly.But L298 is warmed and need a heat sink. I think that a simple mosfet driver with isolated ground could be used for this work. warming means your mosfets are not switching properly or new mosfet's ON resistance is higher than for IRF9540 - which means also lower
I have a basic ciruit in which a PIC is supposed to flash a few LEDs. It flashes on and off PORTA and PORTB (at twice the speed of PORTA). The micro is a PIC16F628A which is setup for using its internal osc. power supply is stable (or at least it should be, 7805 with caps on either side). It works BUT about a quater of the (...)
i build electronic switch with LS7473 jk flip flop togle circuit for switching solenoid and ac motor,but when ac motor on,all digital switch off by him self each time ac relay for motor energized,please help me to solve the problem.thanks before
Yeah i did go thru this site but this site recommends the use of linkswitchII IC (LNK616PG) and a 10pin transformer EE16 for an o/p of 5V n 1A. Recently i hav stripped a nokia charger(duplicate) with specs 5.5V n 0.5A n found that it uses a power transistor (E13003) for the switching purpose and a 6pin transformer. In the (...)
I would suggest you use two 1N5819 diodes as shown in attached schematic near 7805 to prevent 4700uF caps from discharging through it when power fails. Change bax capacitor to electrolytic 10uF. And as Kender suggested, use Voltage supervisor for reset. Is brown-out detect enabled in PIC fuse settings? Try to capture waveforms of 5V (...)
Your realy does not have a supression diode conected between the collector and the supply of the switching opto isolator. It dumps the energy of the coil back into the power supply as the coil de-energises.
It maybe an SMPS based UPS. switching power supplies do not function properly without a minimum load, eg, problems in feedback loop, inductor, etc without minimum load. So, the UPS may turn itself off to protect itself. Nalin74, Some photos would help. Then, it can be better understood.
Also, consider the overall circuit. power loss = (50-5)*5 = 225W for an output power of 25W. Efficiency = (25/250)*100% = 10% So, for a more efficient circuit, a switching regulator should be employed. There are switching regulators available for 5A current or more. One such is L4977 (7A output). Hope this helps. Tahmid.
i had read similar threads but need to confirm that i want to charge my mobile which uses 5v 1.5amp charger and the problem is current rating. can i use 7805 voltage regulator and get 5v 1.5amp current output without burning my mobile? Is their any other IC for regulating 6v 4.5ah battery to 5v 1.5amp? thanks in advance :-)[/
use LM2595 regulator with 100khz switching supply. or use 7805 with any 10A bipolar transister as driver.
Hi, i got i circuit that is powered by USB and it got a PIC on it. There is a 12V battery to supply the circuit if the USB get disconected. The battery is regulated using a simple LM7805 (for now but it can be changed if necessary). My question is, what kind of circuit can i use to perform this switching, from the USB (...)