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From a battery source, I have connected multiple voltage converters (100V, -1500V etc...).

I wish to turn all of this on with a single switch. First of all, will a simple RC filter with large C be sufficient for debouncing?

It is quite important that the converters actually get the full 5 volt from the battery source. How can this be maintained?

I have no experience with connecting Li-ion batteries to my circuit and so I'm mainly asking for input on what I need to consider when doing so. E.g. the effect of battery source resistance and internal resistance of the converters.

EDIT: Here is my current switch and debouncing cap:enter image description here

Max load is ~300 mA. I've understood that I should probably place an efficient voltage converter between the battery and the switch in order to provide a constant 5V.

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  • \$\begingroup\$ simple debounce cct's exist in logic easily found in google images and "Logic Level power FET " switches that can be driven from this logic level. There are many solutions, but you must try harder to define all the requirements for all inputs and outputs with values \$\endgroup\$ – Tony Stewart Sunnyskyguy EE75 May 25 '17 at 5:19
  • \$\begingroup\$ No li-ion battery puts out 5V. What is your power source really, a USB power bank? If so then it will have a built-in voltage converter. \$\endgroup\$ – Bruce Abbott May 25 '17 at 6:46
  • \$\begingroup\$ You seems to be implying a push button switch. Could you use a simple toggle switch? \$\endgroup\$ – Glenn W9IQ May 25 '17 at 10:01
  • \$\begingroup\$ I realize I will have to provide an efficient voltage converter for the battery in order to provide a constant 5V from Li-ion cells. The switch will be a common PCB mountable SPDT switch, i.e. yes I can use any switch deemed optimal. \$\endgroup\$ – toxUP May 26 '17 at 2:12
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Switches can have surprisingly low current rating. Check the switch datasheet. Furthermore, the current in-rush to charge capacitors when the switch makes contact can age the switch prematurely. (I don't know if this is a risk at 5 V.) Using just a capacitor to debounce the signal relies on the resistance of the power source, wires and capacitor to limit the turn-on current and signal rise time.

A safer approach to all this is to use the switch to control a transistor or IC switch (such as TPS22919) which in turn powers the regulators, or to control the regulator(s) enable pin if such exist. Then add a resistor to the switch output to form a RC network with your capacitor (which can now be much smaller). There are many online tools to calculate the values for resistor and capacitor to fit your debouncing time, for example https://www.digikey.com/en/resources/conversion-calculators/conversion-calculator-time-constant

EDIT: To get 5 V from a single-cell Li-ion cell (3.3 - 4.2 V), you can use for example this: https://www.pololu.com/product/2123 It has an enable pin, which you can drive with your switch (and RC network).

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To answer your debouncing question, you could just put a decently sized capacitor after the switch (Probably not necessary as your voltage converters probably have input capacitors). As for input on converting your circuit to using lithium-ion cells, you should firstly check that your circuit works without any problems or shorts. Shorts will probably cause something to explode. Your circuit should work with a lithium-ion battery if it works on any normal supply, just make sure you don't over-discharge the battery or be sure to get one with a protection circuit.

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  • \$\begingroup\$ Thank you. I will definitely confirm that the circuit works with a lab supply before introducing a battery. Can I purchase built-in battery packs with protection circuit and regulated voltage output? Looking quickly on Digikey, I can't seem to find any. \$\endgroup\$ – toxUP May 26 '17 at 2:17
  • \$\begingroup\$ @toxUP Battery packs with built in protection circuits can be found with a simple google search. I don't think Digikey has any rechargeable lithium ion batteries. Based on your needs of 5 volts, you could also get a rechargeable battery bank with usb outputs at your current needs. They should all have protection circuits, voltage regulation, and a capacity gauge. You could easily hack a usb cable to give your desired voltage outputs. \$\endgroup\$ – Alex May 26 '17 at 3:47

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