D
[email protected]
- Jan 1, 1970
- 0
I know the basics of charge pumps but they seem to be limited to
providing integer multiples of the input voltage.
I'm looking for a circuit that given a single available input voltage,
Vin, provides an output voltage, Vout, such that Vout = Vin+10.0volts.
(nice if the circuit actually was tweakable... Vout = Vin + Vadd)
Current requirements for Vout are small. 10-20ma would be
sufficient I think.
Vin should be relatively wide, 12v - 170v would be ideal, 12-48v
would be ok too.
Efficiency doesn't have to be good and output ripple can be pretty
insane. I want to use it to drive high side mosfets on indefinitely.
The gate charge is very tolerant so ripple voltages of a couple of
volts could be handled.
My basic question is: Is such a circuit feasible and simple?
Where should I look for such a beast?
My first thought is since Vin > 10v (or basically Vin > Vadd)
you could use a simple doubling charge pump with the
flying capacitor connected to a current limited
zener diode with a breakdown voltage of 10V (or Vadd).
But at higher voltages this doesn't seem to work well since
the flying capacitor could only be charged with about 10mA
without exceeding the power rating of common zeners.
And of course efficiency would be ultra terrible.
Is there a better way given a Vin to charge a capacitor to
Vadd where Vadd < Vin?
I'm not an electrical engineer so am I missing something
relatively simple?
providing integer multiples of the input voltage.
I'm looking for a circuit that given a single available input voltage,
Vin, provides an output voltage, Vout, such that Vout = Vin+10.0volts.
(nice if the circuit actually was tweakable... Vout = Vin + Vadd)
Current requirements for Vout are small. 10-20ma would be
sufficient I think.
Vin should be relatively wide, 12v - 170v would be ideal, 12-48v
would be ok too.
Efficiency doesn't have to be good and output ripple can be pretty
insane. I want to use it to drive high side mosfets on indefinitely.
The gate charge is very tolerant so ripple voltages of a couple of
volts could be handled.
My basic question is: Is such a circuit feasible and simple?
Where should I look for such a beast?
My first thought is since Vin > 10v (or basically Vin > Vadd)
you could use a simple doubling charge pump with the
flying capacitor connected to a current limited
zener diode with a breakdown voltage of 10V (or Vadd).
But at higher voltages this doesn't seem to work well since
the flying capacitor could only be charged with about 10mA
without exceeding the power rating of common zeners.
And of course efficiency would be ultra terrible.
Is there a better way given a Vin to charge a capacitor to
Vadd where Vadd < Vin?
I'm not an electrical engineer so am I missing something
relatively simple?