causalitist
New Member
I built this circuit that someone else made, i particularily like the ramp speed adjustment! this is for a "bicycle" and a huge 148v motor running on 148v lithium polymers.
im using a tc4422 driver,
i have 4148 diodes on each output of the chip,
timing cap(pin 7 to gnd) is .002 and timing resistor is 1.8k + a 100k pot. i get 8khz-hundreds of khz.
main cap 4" from mosfets is 500c103t250dd2b 10,000uf 250v
then there will be (2) unl4w30k-f metalized film caps + 2 860uf electrolytics directly on the fets inside the controller.
freewheel diode is (2) rurg5060
**broken link removed**
i was going to use (4) irfp4668 200v 8milliohm 130amp mosfets, but
i want transient voltage suppressors from source to drain and there arent any that are usable at 148v but clamp under 200v... so i'm going with the best 250v mosfet i could find(much worse) FDA2712 34MILLI OHM 64amp.
then i can use 1.5ke180ca tvs
im working on the current limiting(0-50amps). i want to use current sense pins for average current limiting(adjustable).. i want to use the allegro AC5755-200 200amp hall effect current sensor(REALLY NICE COMPONENT!), NOT SURE IF IT WILL WORK, but i will try.
shutdown i want to use for a ultra fast short/overcurrent/upper limit backup current limitor.
i will use a 0.001 ohm shunt... which will put off 50mv max.. so i need an opamp to turn 50mv into 1v (or whatever threshold there is at shutdown, sg3525 have 1v)
i plan to use LT1677 or LT1218 op amp for a current sense amplifier.
below is a schematic for a old 36v 4QD controller. its beyond my level, but notice they have a 100k pot from pin 9(compensation) to ground, and the wiper going to pin1(inverted input)..
**broken link removed**
they have the drive mosfet, the regen mosfet... but then they have that bottom mosfet with a 400OHM SHUNT to ground(330ohm+100ohm) between the two is tapped to pin 4:current sense!
whats up with a 430ohm shunt?
looks like a few milliamp flow through the shunt, it is probabily a 1/2watt resistor.. very good idea to not add resistence to the power path. but the output of this would be alot of volts to the cs pin!
i have a feeling that the 100k pot on the comp pin is related somehow.
this is what im trying to figure out... the 100kpot, and the high resistence shunt.
i like the low battery cut off, i think i'll do that too.
i still have no idea what the 100k pot does.. pin 9 (compensation) apparently adjusts the gain of the op amp with inverted/non inverted (pin 1,2) inputs... and a negative signal will shut down the chip.
i'm very curious.
i will post pics of my controller soon
the big motor below is what im using, once i find a 90 degree gearbox.. and this is going on a 18speed mountain bike!!! wooo hoo!
**broken link removed**
im using a tc4422 driver,
i have 4148 diodes on each output of the chip,
timing cap(pin 7 to gnd) is .002 and timing resistor is 1.8k + a 100k pot. i get 8khz-hundreds of khz.
main cap 4" from mosfets is 500c103t250dd2b 10,000uf 250v
then there will be (2) unl4w30k-f metalized film caps + 2 860uf electrolytics directly on the fets inside the controller.
freewheel diode is (2) rurg5060
**broken link removed**
i was going to use (4) irfp4668 200v 8milliohm 130amp mosfets, but
i want transient voltage suppressors from source to drain and there arent any that are usable at 148v but clamp under 200v... so i'm going with the best 250v mosfet i could find(much worse) FDA2712 34MILLI OHM 64amp.
then i can use 1.5ke180ca tvs
im working on the current limiting(0-50amps). i want to use current sense pins for average current limiting(adjustable).. i want to use the allegro AC5755-200 200amp hall effect current sensor(REALLY NICE COMPONENT!), NOT SURE IF IT WILL WORK, but i will try.
shutdown i want to use for a ultra fast short/overcurrent/upper limit backup current limitor.
i will use a 0.001 ohm shunt... which will put off 50mv max.. so i need an opamp to turn 50mv into 1v (or whatever threshold there is at shutdown, sg3525 have 1v)
i plan to use LT1677 or LT1218 op amp for a current sense amplifier.
below is a schematic for a old 36v 4QD controller. its beyond my level, but notice they have a 100k pot from pin 9(compensation) to ground, and the wiper going to pin1(inverted input)..
**broken link removed**
they have the drive mosfet, the regen mosfet... but then they have that bottom mosfet with a 400OHM SHUNT to ground(330ohm+100ohm) between the two is tapped to pin 4:current sense!
whats up with a 430ohm shunt?
looks like a few milliamp flow through the shunt, it is probabily a 1/2watt resistor.. very good idea to not add resistence to the power path. but the output of this would be alot of volts to the cs pin!
i have a feeling that the 100k pot on the comp pin is related somehow.
this is what im trying to figure out... the 100kpot, and the high resistence shunt.
i like the low battery cut off, i think i'll do that too.
i still have no idea what the 100k pot does.. pin 9 (compensation) apparently adjusts the gain of the op amp with inverted/non inverted (pin 1,2) inputs... and a negative signal will shut down the chip.
i'm very curious.
i will post pics of my controller soon
the big motor below is what im using, once i find a 90 degree gearbox.. and this is going on a 18speed mountain bike!!! wooo hoo!
**broken link removed**
