In sci.electronics.design said:
Does anyone know of a way to increase DC voltage WITHOUT using any
kind of oscillator? Can't use any DC-DC converters that rely on
oscillators of any kind.... transformers, buck boosts, etc....
because it goes on a high density PCB wtih lotts of Audio and RF.
I thought of the LED-and-photocell thing too. There's something
that might have a little more efficiency, that "technically" meets
your specs (it's "not an oscillator"), but is even less practical: A
dynamo (motor-generator). So, now that you've totally dismissed me...
Presuming you're concerned about audio and RF interference
generated by the voltage converter, some sort of sinusoidal (so almost
all of its current pull variation and radiation is at the fundamental
frequency) RF oscillator (in the 20kHz to 200kHz range, low enough
that it radiates very little) is your best bet. There's a model of
studio condenser microphone (I forget what model, it was discussed on
rec.audio.pro) that uses an RF oscillator and transformer to generate
its 50-odd volts bias voltage (if you haven't guessed, that's a
demanding, low-noise application). A well-designed (probably Class A,
or for better efficiency, push-pull Class AB) converter circuit should
not generate significant signal interference to nearby circuitry.
I'm trying to convert a DC input that unreliably varies from 10.6V -
16V @ 150mA up to any voltage greater than or equal to 16V and can't
drop under 100mA . FYI, I'm using a 15Vzener to limit anything
greater than that.
Currently we're using a simple op amp with gain to provide the higher
voltage but it causes the necessity for several dynamic circuits to
develop bias voltages throughout the circuit that change with the
input. What I'm trying to do is eliminate all the extra circuitry
that accounts for varying biases. If I can accomplish this, it will
reduce component count by 20% and PCB real estate by 30%.
This ones a poser....several engineers at a Fortune 50 company and I,
have been scratching our heads over it. If I haven't been absolutely
clear on what I need, please let me know which parts need explaining.
Thanks in advance, this NG has always rocked.
Great, send us our consulting fee.