I am using these on my SSR’s. Good for 100A, 4mOhm, 80v. PG-TDSON-8. Tiny package but big current.
BSC040N08NS5ATMA1 Infineon Technologies | Mouser
BSC040N08NS5ATMA1 Infineon Technologies | Mouser
My circuit build used DMT10H010LK3-13 SMT MOSFETs, Dpak, 100V, 6.5milliohm. I don't think I found any dual-MOSFETs with good enough ratings, but Dpak are small enough really, you need to get some heat out of the things at higher power levels - a heat-slug is needed.
IIRC the dual devices with heat-slugs were all asymmetric for power conversion use.
What about these??
How is there heat generated with such low Rdson?
SQJQ910EL-T1_GE3 Vishay / Siliconix | Mouser
How is there heat generated with such low Rdson?
SQJQ910EL-T1_GE3 Vishay / Siliconix | Mouser
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Well 100W into 4 ohms is 5A rms, which through 8.6 milliohm is 215mW, enough to get small packages distinctly warm - unless you can afford a lot of pcb area as heatsink for the drain tabs.
And I just had another search for possible MOSFETs - over 100V seems to command a non-trivial price premium it seems, this FDMS4D0N12C was a notable performer at 120V and 3.3 milliohm, though expensive: https://uk.farnell.com/on-semiconductor/fdms4d0n12c/mosfet-n-ch-120v-114a-pqfn/dp/2895643RL
For dual MOSFETs I found 100V 13mOhm: FDMS8090, and 80V 7mOhm: NVMFD6H840NL - seem to be more symmetric dual MOSFETs than when I last looked
For dual MOSFETs I found 100V 13mOhm: FDMS8090, and 80V 7mOhm: NVMFD6H840NL - seem to be more symmetric dual MOSFETs than when I last looked
Accuphase uses TK160F10N1 transistors for protection in many of its new designs, RDS(ON) = 2.0 mΩ; VDS = 100 V.
Another small device used by Accu: TPH1R306P, RDS(ON) = 1 or 0.96 mΩ !!! (dep. on version PL or P1), but limited VDS = 60V.
Greetings. Sorry for jumping on this thread so late in the game. It's because I just had a relay-based speaker protection circuit fail in one of my diy amps (in use for years) and I am thinking about switching to a SSR. So I've been looking at using the VOM1271 with TK72E12N1's mentioned by Bonsai and others.
Any suggestions about the sensing part of the solution such as turn on delay and DC detection? Tips would be appreciated.
Any suggestions about the sensing part of the solution such as turn on delay and DC detection? Tips would be appreciated.
Here is the delay relay circuit I employ:
And I've adapted Fig 1 (here: Loudspeaker Protection and Muting) for DC detection, Doug Self also published a version that is popular.
Mike
And I've adapted Fig 1 (here: Loudspeaker Protection and Muting) for DC detection, Doug Self also published a version that is popular.
Mike
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Mike, Thanks for taking time to respond.
The current circuit is Rod Elliot's P33 so I've considered using the P198 MOSFET relays as he suggests, but don't have room for 4 additional boards. And . . . something new will be more fun. BTW, the failure was my bad. I shorted something, not sure what, to 60VDC and took out a perfectly good DMM probe at the same time.
I'll check out Mr. Self's solution as well as your's.
Thanks again,
Neel
The current circuit is Rod Elliot's P33 so I've considered using the P198 MOSFET relays as he suggests, but don't have room for 4 additional boards. And . . . something new will be more fun. BTW, the failure was my bad. I shorted something, not sure what, to 60VDC and took out a perfectly good DMM probe at the same time.
I'll check out Mr. Self's solution as well as your's.
Thanks again,
Neel
@Michael Bean
do I need both circuits for DC protection + relay? if yes, how do I combine them? Thanks in advance!
it just feels schematic 1 is incomplete and it requires some sort of DC detection circuit (that is not shown)
do I need both circuits for DC protection + relay? if yes, how do I combine them? Thanks in advance!
it just feels schematic 1 is incomplete and it requires some sort of DC detection circuit (that is not shown)
You need a DC sense circuit. Something like the first block here using optoisolator followed by comparator to detect threshold for DC. Additional comparator is for turn on delay and to detect external signal for muting option. Comparator is open collector logic which drives gate driver on mosfet relay.
