Latching over-current switch

[kender]

Colleagues,

Do you know an IC, which works as a latching over-current switch. Once the current reaches the threshold, it should turn it off until PIC turns it back on. I could construct something like this out of MAX890 and an S-R latch, but one IC would be a lot better, becasue space is premium in my application.

Thanks,
Nick

[SherpaDoug]

The MAX890 seems to regulate the current, not shut it off if it exceeds the limit. If you want to use the MAX890 could you place Rset between pin 5 and pin 8 instead of between pin 5 and GND? As soon as there is a fault pin 8 goes high, making the chip think there is a bigger fault and shutting down. Then the PIC could have a I/O pin connected to pin 8 that would normally be tri-state. Pulling it low would override the MAX890 pin 8 /Fault signal and get it running again.
You should be able to get a "foldback" effect if you want by adding another resistor about 10 x Rset from pin 5 to GND so it wouldn't shut completely off.
Don't try any of this without reading the datasheet from cover to cover.

Finally...A good analog question on this C compiler BBS! ;-)
_________________
The search for better is endless. Instead simply find very good and get the job done.

[Guest]

try the max4373/4/5

[Steve H]

Linear tech and others make USB port current limiters. I've used several from Linear. Some self reset some latch off untill as you say something resets them. Do a search from your fav. IC vendoe and look for USB power solutions.

Steve H.

[Mark]

Are you trying to do short circuit protection? Or are you wanting to set a specific current to trip on?

[kender]

I want to set a specific current to trip off, and then have the PIC turn the power back on and reinitialize the subsystem.

MAX4374 looks promissing. If only it had a built-in MOSFET.

Steven, I have tried searching the Linear Technology's site for USB current limiter, but couldn't find anything useful. Could you give me the URL or the part number for the IC you were using?

Thanks,
Nick

[Steve H.]

After looking for these myself a better search would have been for: hot swap, PCMCIA power controllers, circuit breakers, etc. They don't seem to have them broken out into a USB cat. anymore...

From TI -
TPS2030 Yes No No No 8PDIP,8SOIC 0.99 0.22A, 2.7-5.5V Single Hot-Swap IC Hi-Side MOSFET, Fault Report, Act-High Enable
TPS2031 Yes No No No 8PDIP,8SOIC 0.99 0.66A, 2.7-5.5V Single Hot-Swap IC Hi-Side MOSFET, Fault Report, Act-High Enable
TPS2032 Yes No No No 8PDIP,8SOIC 0.99 1.1A, 2.7-5.5V Single Hot-Swap IC High-Side MOSFET, Fault Report, Act-High Enable
TPS2033 No No No No 8PDIP,8SOIC 0.99 1.65A, 2.7-5.5V Single Hot-Swap IC Hi-Side MOSFET, Fault Report, Act-High Enable
TPS2034 No No No No 8PDIP,8SOIC 0.99 2.2A, 2.7-5.5V Single Hot-Swap IC Hi-Side MOSFET, Fault Report, Act-High Enable
TPS2020 Yes No No No 8PDIP,8SOIC 0.99 0.22A, 2.7-5.5V Single Hot-Swap IC Hi-Side MOSFET, Fault Report, Act-Low Enable
TPS2021 Yes No No No 8PDIP,8SOIC 0.99 0.66A, 2.7-5.5V Single Hot-Swap IC Hi-Side MOSFET, Fault Report, Act-Low Enable
TPS2022 Yes No No No 8PDIP,8SOIC 0.99 1.1A, 2.7-5.5V Single Hot-Swap IC Hi-Side MOSFET, Fault Report, Act-Low Enable
TPS2023 No No No No 8PDIP,8SOIC 0.99 1.65A, 2.7-5.5V Single Hot-Swap IC Hi-Side MOSFET, Fault Report, Act-Low Enable
TPS2024 No No No No 8PDIP,8SOIC 0.99 2.2A, 2.7-5.5V Single Hot-Swap IC Hi-Side MOSFET, Fault Report, Act-Low Enable
UCC3912 No No Prog Prog Yes 16PDIP,16SOIC,24TSSOP 2.15 0-3A, 3-8V Single Hot-Swap IC Hi-Side MOSFET, Commercial Temp.
UCC3915 No No Prog Prog Yes 16PDIP,16SOIC,24TSSOP 2.40 0-3A, 7-15V Single Hot-Swap IC Hi-Side MOSFET, 100µA IQ in Sleep Mode, Comm. Temp.
UCC39151 No No Prog Prog Yes 16PDIP,16SOIC,24TSSOP 5.20 0-3A, 7-15V Single Hot-Swap IC Hi-Side MOSFET, 20mA IQ in Sleep Mode, Comm. Temp.
UCC3916 No No Prog Prog Yes 8SOIC 1.60 1.65A, 4-6V Single Hot-Swap IC Hi-Side MOSFET for SCSI Terminator Hot Swap, Comm. Temp.
UCC39161 No No Prog Prog Yes 8SOIC 2.50 0.6A, 4-6V Low Current Single Hot-Swap IC Hi-Side MOSFET, Comm. Temp.
UCC3918 No No Prog Prog Yes 16PDIP,16SOIC 2.20 0-4A, 3-6V Low RDSON Single Hot-Swap IC Hi-Side MOSFET, Comm. Temp.
UCC2915 No No Prog Prog Yes 16SOIC 3.93 0 to 3A, 7 to 15V Single Hot-Swap IC Hi-Side MOSFET, 100µA IQ in Sleep Mode, Industrial Temp.
UCC2918 No No Prog Prog Yes 16SOIC 3.64 0-4A, 3-6V Low RDSON Single Hot-Swap IC Hi-Side MOSFET, Industrial Temp.
TPS2370 No No No Prog Yes 8SOIC,8TSSOP 1.25 IEEE802.3af Power Interface Switch For Power-Over-Ethernet (PoE) Powered Devices (PD's)

From Linear: LTC1153, LTC1696
http://www.linear.com/pc/viewCategory.do?navId=H0,C1,C1003,C1142
(The linear site went down when I was looking, so check them for more)

From Maxim: http://www.maxim-ic.com/HotSwap.cfm

That list will keep you going for an hour or so... :-)

Steve H.