P-FET Power Switch

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Yuseungho
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Last seen: 2 years 3 months ago
Joined: 2020-04-29 03:49
P-FET Power Switch

Dear,

I'm using the device SLG46517M which has two P-FET power switches. Now, I'm testing the device in emulation mode

with the advanced board connected to the computer. Here I attatched the schematic and how I configured socket connection.

 

First, is the connection of P-FET that I understood right?

(VI1: Power switch 0 input, VO1: Power switch 0 output / VI2: Power switch 1 input, VO2: Power switch 1 output)

If it's right, according to the schematic,

I think when the voltage A is higher than 1000mV, after a short delay, 'ON' signal goes low, then P-FET will be turned on.

After that, voltage B will be shown at PIN 7.

 

But the problem is that there's always a signal shown at PIN 7 no matter how the ON signal is.

The more strange thing is if I applied the sinusoidal signal with 3Vpp, PIN 7 shows half-wave signal which is above the 0.

I think I misunderstood the socket connection. 

Would you please tell me how should I connect the PIN to use the P-FET switch?

One more question, is it possible to use the P-FET switch in GPAK as a switch connecting to the ground?

Thank you.

Regards,

Seungho Yu

 

Attachment: 
Device: 
Device Number: 
SLG46517M
olehs
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Last seen: 1 year 7 months ago
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Joined: 2018-02-07 11:40
Hi Yuseungho, 

Hi Yuseungho, 

Thanks for your activity! 

Yes, the schematic is correct and your understanding is correct as well. 

The Power Switches in the SLG46517 have active-LOW logic. When ON is HIGH, the power switch will be open. When ON is LOW, the switch will be closed. Did you use some load (let's say Pull Down resistor) on the output, you may not see anything if you just have a Scope connected to the PIN. 

Yes, you can use a P-FET as a switch connecting to the ground, but pay attention that the P-MOS power switch designed to switch 1.71 to 5.5 V power rails up to 2A in each channel. 

Best regards, 

Oleh Sapiha