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Miscellaneous dev boards to test the components of the PROVES Kit on a smaller scale.
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Camera Board Power Circuitry Testing #5

Open NicoleMaggard opened 4 months ago

NicoleMaggard commented 4 months ago

Introduction

Only you can test the Camera Daughter Board Power Circuitry! The Intention behind the power circuitry on the camera daughter board was to allow the toggling of power to the board to allow the camera to cool down. This will be an essential function to operating the camera in space.

The Theory

The circuitry implements two MOSFETs to control power to the board. The control input is connected to the gate of the NMOS Transistor seen below. When the control input goes to a logic "high," the NMOS transistor is intended to pass ground to the gate of the PMOS transistor which should turn the transistor on, connecting the input power to the daughter board 3.3V line. When the control input goes to a logic "low," the NMOS transistor is intended to be off and the input power line is then fed to the gate of the PMOS transistor which should keep the input power line separated from the daughter board 3.3V line. image Is there an issue with this conception of the operations of this circuitry? Are different transistors suggested?

The Possible Testing

Voltage levels should be taken to verify operations of the circuitry. For instance, when 3.3V is applied to the control input on the gate of the NMOS transistor, does ground pass through to the drain of the NMOS transistor/ the gate of the PMOS transistor? Additionally, what is the voltage on the source of the PMOS transistor in this case? Replicate these same measurements but for also when the control input is set to ground. image Please let me know if there are any issues or concerns that arise from this basic functional tests!

JmGeringer commented 4 months ago

Pwr control Low:

PMOS: G: 3.3 D: 3.3 S: 2.56

NMOS: G: 0 D: 3.3 S: 0

Pwr contorl High:

PMOS: G: 0 D: 3.3 S: 3.2

NMOS: G: 3.3 D: 0 S: 0

Here are the values i got when doing the testing. The values match what the operation is supposed to be. what i noticed though is that when i jumped the NMOS with 3.3V to put it in the "high" state. It stayed in that state even when i disconnected it from the 3.3V. like it toggled on. when i tried to toggle it back down to ground "low" it wouldn't change. It stayed at 3.3V.