Announcements

Curious on how you can apply MOSFET to Smart Home Appliances? Register for the ASEAN Smart Home Appliance Webinar here to find out how.

Tip / Sign in to post questions, reply, level up, and achieve exciting badges. Know more

MOSFET (Si/SiC) Forum Discussions

yadavjay
Level 1
First solution authored 5 sign-ins First like given
Level 1

Hello

We are using the P channel MOSFET IRLM5103 two switch the 12V for the analog Application. the voltage is switched from Source to drain when the MOSFET is ON.  Also when there is 154V volt at the input (Drain) then there will be 12.5V constant at the output (Source) of the depletion mosfet. due to which the the body diode of the IRLM5103 will be the forward biased and the some of the current will flow to the +12V source. how much current will flow through the body diode when that body diode will forward biased ? what will impact on the +12 Source ?

I have attached the schematic of the application.

 

0 Likes
1 Solution
yadavjay
Level 1
First solution authored 5 sign-ins First like given
Level 1

Hello sushank,

Thanks for the reply , i can check that in simulation but i need that reverse current to be calculated in my calculation. for that how should i consider the drop across the diode its not given in the datasheet for the low leakage current.

I have checked the actual result as well there, I got 12.5V as output at source of the depletion MOSFET and the current which is flowing through the body diode of IRLML5103 is of 198uA at 85 deg. but in calculation how can i consider the drop of Body diode ?

View solution in original post

0 Likes
5 Replies
sushank
Moderator
Moderator 25 solutions authored 100 sign-ins 50 replies posted
Moderator

Hi there, 

in the simulation itself you can check the drain current, negative current will be the body diode current. 

Thanks. 

0 Likes
yadavjay
Level 1
First solution authored 5 sign-ins First like given
Level 1

Hello sushank,

Thanks for the reply , i can check that in simulation but i need that reverse current to be calculated in my calculation. for that how should i consider the drop across the diode its not given in the datasheet for the low leakage current.

I have checked the actual result as well there, I got 12.5V as output at source of the depletion MOSFET and the current which is flowing through the body diode of IRLML5103 is of 198uA at 85 deg. but in calculation how can i consider the drop of Body diode ?

0 Likes
sushank
Moderator
Moderator 25 solutions authored 100 sign-ins 50 replies posted
Moderator

hi, 

is D2 the body diode you are referring, because you dont need to place separate diode as body diode. 

0 Likes
yadavjay
Level 1
First solution authored 5 sign-ins First like given
Level 1

Hello ,

that i placed for the Understanding or the visibility because in ltspice there is no any body diode shown in the symbol so i added for the understanding its integrated body diode only.

0 Likes
sushank
Moderator
Moderator 25 solutions authored 100 sign-ins 50 replies posted
Moderator

Unfortunately,  there is no hard and fast rule to calculate and formulate the body diode current. if still you want to formulate the current than you need to prepare equivalent circuit in reverse mode when diode comes in action and apply the KCL. make sure that in formulation time dependency should be there. 

Thanks.

 

0 Likes