Increasing maximum current but keeping voltage same

Caspar Valentine

Jun 13, 2017
2
Hi, I've got a 0-5V 5MHz (high frequency for a smoother analogue signal) PWM signal that can provide a maximum of 30mA, that goes into a low pass filter so I can convert it into an analogue signal.

I want to be able to draw up to 2A (without overheating or setting it on fire of course). I could just put a transistor, but correct me if I'm wrong, but the voltage drop across a transistor varies depending on the current drawn, and I need to know the exact voltage vs the PWM cycle.

Is there any circuits or chips that'll let me do this? Thank you

davenn

Moderator
Sep 5, 2009
14,178
I want to be able to draw up to 2A (without overheating or setting it on fire of course). I could just put a transistor, but correct me if I'm wrong, but the voltage drop across a transistor varies depending on the current drawn, and I need to know the exact voltage vs the PWM cycle.

how much current is drawn is set by the load resistance
if the voltage and the load resistance are fixed, then the current will also be fixed

Caspar Valentine

Jun 13, 2017
2
how much current is drawn is set by the load resistance
if the voltage and the load resistance are fixed, then the current will also be fixed

The load resistance varies. I want the voltage to be fixed, the same before and after the transistor, but the current to vary with the load resistance.

davenn

Moderator
Sep 5, 2009
14,178
The load resistance varies. I want the voltage to be fixed, the same before and after the transistor, but the current to vary with the load resistance.

OK it way beyond time you supplied a circuit diag to show us what you are trying to achieve

Harald Kapp

Moderator
Moderator
Nov 17, 2011
13,179
but the current to vary with the load resistance
It is still important to know the max. current as requested by dave in post #2.
Any analog amplifier with gain=1 and able to support the max. current required will be suitable for this application.

Note that this will incur a comparatively high cost in terms of power dissipation in the linear amplifier, thwarting the use of pwm as a means of saving power.

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