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For my application I have two AD633 Analog Multipliers that need a ground referenced +-15V supply. I have a 24VDC and a 8 VDC supply to use, but i would prefer to use the 24V supply. I've looked at several options, But most used too many components, So am after a solution that uses as few components as possible and will last for a long time.

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Bruno Carreira
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  • you may get a +12/-12 from the 24V then use a boost to 15V each side (positive & negative) –  Aug 30 '19 at 22:26
  • I cant. I need to maintain the same ground for everything – Bruno Carreira Aug 30 '19 at 22:29
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    What does "simple" mean to you? Please tell us what options you have discarded so we don't waste time suggesting them to you. – Elliot Alderson Aug 30 '19 at 22:42
  • Hmmm... if you make -Vs=GND and +Vs=24V, then the AD633 will "think" that +12V (half way between -Vs and +Vs) is ground (notice that the AD633 has no GND pin), so you can use it as your virtual ground. So you can shift your input signals up by 12V and shift your output down 12V (if you really need to). – joribama Aug 30 '19 at 22:50
  • But the output of AD633 will be refered to 12v, so the output will be 12v+output. I need the output refered to the real ground – Bruno Carreira Aug 30 '19 at 23:07
  • Elliot, by simple i mean few components. I ruled out charged pump and virtual ground. – Bruno Carreira Aug 30 '19 at 23:08
  • If you want your input referred to ground you can subtract 12V from the signal using a simple differential amplifier topology, like the one proposed here: https://electronics.stackexchange.com/questions/18264/subtracting-two-voltages-using-an-op-amp keep in mind that the op amp needs to be able to drive its output all the way down to ground and that any negative voltage will be clipped. – joribama Aug 30 '19 at 23:30
  • First you need specs on SNR and accuracy , or tolerance error, then you may consider a design, not before – Tony Stewart EE75 Aug 31 '19 at 01:34
  • Why rule out a charge pump? It is more simple and more quiet than a flyback. MIC1557, caps and diode, output diode is a zener to regulate. – AnalogKid Aug 31 '19 at 11:59
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    AD633 has *differential* inputs, so the input voltage is not ground-referenced. It has an *offset pin* to set the zero output voltage too. So it does not care about GND. What is important is the input/output voltage range, which is +/-10V and +/-11V resp with +/-15V supplies. So, input voltage range is [5V above neg supply to 5V below pos supply]. You can use any supply voltages you want as long as the input and output voltages you require are within acceptable range. So, please clarify... – bobflux Aug 31 '19 at 12:51
  • For example, if you use a +24V/0V supply for AD633, it will accept input voltages between 5V and 19V, and it will output between 4V and 20V. Also how much current do you need? Other loads like opamps? Is the signal AC or DC? (if AC, you can AC-couple it and don't need a negative supply). – bobflux Aug 31 '19 at 12:53

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You can use inverting charge pump, buck-boost voltage inverter or a virtual ground op amp based solution to split rails.

This is one example component which can provide \$-15\,\mathrm{V}\$. It is a simple dc-to-dc converter module.

Part number: P7805-Q24-S15-S
enter image description here

Do not miss to notice the pin numbering in both configuration.

Elliot Alderson
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User323693
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