Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [mc34063]

38 questions
7
votes
1 answer

Step-down with external mosfet - why heavy current surges?

I built this circuit, which is supposed to deliver currents up to 20 amps (when everything else works...). The purpose is (eventually) to build a constant current source (as opposed to a constant voltage source) which will be used for anodizing…
jjstcool
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5
votes
1 answer

MC34063 Switching Regulator IC: When was it introduced?

I'm a bit curious when the classic MC34063 IC was introduced, today available as the -A version (MC34063A). I'm trying to get an idea when some of the classic switching controller ICs were introduced because it marks the point when switchers started…
zebonaut
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3
votes
3 answers

MC34063 step-up unstable operation

I am building a 3.3V -> 15V/100mA boost converter using MC34063. I have used formulas in the datasheet to calculate values of components. Then I spotted some oscillations in Vout and instability of inductor current. Is this normal behaviour of…
Vasiliy
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3
votes
1 answer

Confusion with MC34063 Vsat

I'm currently designing an e-ink panel driver. My choice is MC34063 for generating required voltages and I want to use two of these for step-up and inverting converters. However I'm somewhat confused with the saturation voltage needed for…
Lisu
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3
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1 answer

MC34063 issue. Switches off every cycle

I am using MC34063 in step down configuration but the converter switches off every cycle. Following are the calculations and specifications: Vin - 9 to 12V Vout - 5V Imax - 0.3A Rsc - 0.36 ohms L - 47uH 1.6A Ct - 270pf I have tried reducing the…
karanbanthia
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2
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1 answer

3.7- 5v boost converter issue

I am trying to do boost converter with using mc34063 ic for my project. When I simulate the circuit on LTSpice with 3.7V input. I can get 5V output without any problem. However, when I change the input voltage to 4.2V (which is fully charged 3.7v…
ratatosk
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2
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2 answers

Buck Converter Capacitor and Inductor Characteristics

I'm trying to make a buck converter with this mickey-mouse MC34063A chip that will step-down +5V to +3V3 up to 500 milliamps. I've gone through the calculations by hand and validated them with an online calculator as well. My PCB works great with…
jm567
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2
votes
5 answers

MC34063 based converter accoustic noise

I am trying to make nixie clock and I use MC34063 for buck/boost converters. The nixie tubes require 180 V to operate and the microcontroller and LEDs need 5 V. I use external 20 V power supply as a source. Here are the circuits: 5V 180V When the…
George
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2
votes
1 answer

MC34063A step up voltage converter

i need change 5v to 12v that it use to supply a device; for this use MC34063A step up voltage converter; this site can calculate the parameter. i have problem all thinks is OK but i have same voltage at output! how to find my mistake ?
Mahdi KhosroAnjom
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2
votes
2 answers

Power Supply : How to keep SMPS always above the post-regulator that follows it

I'm trying to find a way of building a new power supply for my workshop, in order to keep it small and not so hot I will be using a spare xformer to step down mains to 24v and then a variable buck converter to adjust it (and CC mode, displays and…
k_orolev
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2
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2 answers

Double polarity pulse with one single power source and virtual spdt switch

I have a problem in the design or my circuit. I need send data at a maxixum bitrate of 12000 bits /second. The high value should be +12v and the low value should be -12v providing at least 35mA of current. I initialy thought that I could easily get…
smitchel
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2
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1 answer

MC34063 P-MOSFET driver?

I've got a successful buck converter design using an LM3485. It's got a MOSFET gate driver output pin that swings between Vin and Vin-5V - perfect. My MOSFET is a SQ1431EH-T1-GE3. It has a maximum Vgs of 20 volts and Vds of 30 volts. The input…
nsayer
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1
vote
1 answer

Annoying noise when there is no load on MC34063 in boost configuration

I'm using MC34063 in step-up configuration to charge 4S lithium-ion battery pack. Input is 12 V output is set to 16.9 V. Module consists of a 0.33 Ω current sensing resistor, a shielded 2 A 100 uH inductor, SS34 Schottky diode and 100 uF 1206 SMD…
AKTanara
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1
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1 answer

MC34063 output voltage rises with current draw

In my current project I implemented two MC34063 switching converters to provide a 3.3V and a 4V rail. Testing the converter circuitry I found some odd behaviour. Unloaded I get a solid 4.0V, but when applying a 40Ω load the output voltage rises to…
Julian F. Weinert
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1
vote
1 answer

MC34063 boost circuit drops voltage when adding load resistor in LTspice

I am using LTspice to simulate a MC34063 boost circuit to bring a 3.7 V Lipo battery up to 5 V in order to power a Raspberry Pi Zero. When I simulate the circuit it works just fine (shown in the first picture): However, when I add a load resistor…
Ritz123
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