Author Topic: [HELP] parts or circuit to control 5v rail with min loss  (Read 561 times)

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Offline allenpan

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[HELP] parts or circuit to control 5v rail with min loss
« on: March 21, 2016, 12:55:03 pm »
[HELP] parts or circuit to control 5v rail with min loss

long story short: I have MCU that use 2.1v for GPIO, and i have a separate 5v circuit, i would like to use the 2.1v logic to switch 5v on an off... (5v will be up to 200mA, typical 100mA)

feel free to suggest other parts or circuit..but simple with min part counts

i did explored

BJT (2N3904): problem, the Vce has 0.6v drop at 200mA
Enhanced n-MOSFET: problem, Vgs threshold = 1.8v-2.1v too close to my logic voltage, and Vds = 0.6 drop as well...

any other suggestion? i was thinking get another controllable voltage regulator, but i dont know if that is good idea or put too much load on the 3.3v rail..

-Allen
 

Offline ovnr

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Re: [HELP] parts or circuit to control 5v rail with min loss
« Reply #1 on: March 21, 2016, 01:17:32 pm »
Use a dedicated PDU IC, like the TPS22929D?

Alternatively, just use a BJT to control your FET. Or a cheap gate driver.
 

Offline soligen

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Re: [HELP] parts or circuit to control 5v rail with min loss
« Reply #2 on: March 23, 2016, 03:31:22 pm »
The AO3400 has a Vgsth under 1.5V.
 


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