Thursday, July 21, 2016

Verifying the MOSFETs´ RDS(ON)

. . . being used to BJT-s i always thought the RDSON being some illustrative variable that has nothing to do with reality - amazingly enough the tests i performed verified it being NOT a theoretical figure !

used the MOSFETs (IRFZ44N and BUK455-60A) unmounted from cordless drills´ speed adjustment circuits

the IRFZ44N existed in Spice DB but for the BUK455-60A i used a model compilation method described in the [LT Spice Tutorial 6] website (which actually resulted in better match with reality this time ??)

 as for RDS(ON)
as and for directly measured ID, UD, UG

ah! - also modified in ↑that↑ spice tutorial the files RDSon test jig and Switching Time Test Jig coz they were totally impractical to use for given purpose (fine tuning your MOS-Fet models) respectively to Cust MosFETs - 01.asc and Cust MosFETs - 02.asc (note that you have partially pre-calculate and modify accordingly the component parameter values to get your response right)


PS! Since the power supply (Mod.: SMP-100KB, Rev.: A3, Date Code: 8945, +12Vdc/3.75A - output) was not very stable (or depended on it´s ~AC input ???) the source data can be trusted from 1 to 3 digits (depending on conduction state of the FET and stability of the PSU) and contains extra to that the unknown systematic +other errors of the multi-meters -- this was not intended to be a precision measurement anyway - but for setting the apx. (static) device margins (near +25°C).

also there were used voluntary statistical alterations to guess better the values required to form a "believable" (?accepatable) output for RDS .


Saturday, July 9, 2016

rev. +1.2V Linear Voltage Regulator with Current Limit

not built in real yet /!\ e.g. possibly no reverse pol. prot. + unknown amount of spec. not handled states ...