in the name of allah the merciful
can any one help me with away to protect a dsp against negative wave and more than 3.3v
i used acircuit attached , the function of diodes is to clip wave more than 3.3 and less than zero
when taking in concedration the voltage drop of diodes it’s clip at -.7 not zero and at 2.6 not 3.3
can any one knowing another way to do this ???
i’m abeginner and needs help please
You’ve got the right idea with the diode, but instead of putting it in series with the power supply, try putting it antiparallel. In other words, across the voltage source – but in a direction opposite of current flow.
That way, under normal operating conditions, the diode is turned off and doesn’t conduct. But if the voltage is reversed, the diode absorbs all the current. Protecting from overvoltage is a little more difficult. Although you can try to get a zener diode/resistor to work, but you have to pay attention to current consumption a lot. An easier solution is to use a MAX6397 (or something similar) to disconnect the DSP if too much voltage is fed into it.
How’s that sound?
Building off of the Zener idea, you can put a Zener diode in ‘anti-parallel’ with the power supply, with a [PTC between the VCC and the supply pin on the diode. If voltage is applied backwards, the Zener is effectively a short, which triggers the PTC. If a voltage above the reverse voltage of the Zener is applied, once again, the Zener triggers, becomes a short, and triggers the PTC.](Resettable Fuse PTC - COM-08357 - SparkFun Electronics)