On Sat, 3 Oct 2015 11:09:40 -0700 (PDT), dagmargoodboat@yahoo.com wrote:>12v automotive SSR, to replace a failed $35 unit in my car. > > Q3 > | |-------+---O > | |<-. | > D2 .---+-------+---' |--+ .---' > .-----. | |C1 | | / \ TVS > .--------------------|~ +|--' |10nF .-. R4 | --- > | T1b 500uH | | --- | | 22K | | > '-----. . . . .------|~ -|--. --- '-' | | > '-'-'-'-' '-----' | | | | | > --------- '---+-------+--------+----+---O > --------- > .-.-.-.-. > .------' ' | ' '-------. > | T1a| 1mH | > | | | > O--------+----+----. | > | | | | > | .-. .-. | > | R1 | | R2 | | | > |10K | | 10K | | | > | '-' '-' | > | | ===== | | > \| | .-.-. | |/ > |---+--' ' '--+----| > .<| T1c |>. > | Q1 10uH Q2 | > | | > '----------+-----------' > | > .-. > | | R3 > | | 470 > '-' > | > | > LED1 V ~~> > --- > | > | > V D1 > --- > | > O------------' > >Cheers, >James Arthur[snip] How much current in the load? Might have some SOA problems with the soft turn-on/turn-off?? Might make a Schmitt arrangement, charge up cap _then_ connect to gate and vice versa for turn-off. ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: skypeanalog | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.
A very silly circuit
Started by ●October 3, 2015
Reply by ●October 3, 20152015-10-03
Reply by ●October 3, 20152015-10-03
On Saturday, October 3, 2015 at 7:33:32 PM UTC-4, John Larkin wrote:> On Sat, 3 Oct 2015 16:10:17 -0700 (PDT), dagmargoo...@yahoo.com > wrote:> >They're slow, and expensive, but neat. I'm not sure if they come sufficiently > >hefty to run a radiator fan, and small enough to fit in a 2 x 1 x .5" metal case > >though. > > I mean the little ones, like this: > > http://www.digikey.com/product-detail/en/TLP191B%28TPR,U,C,F%29/TLP191BFTR-ND/871239 > > Really cool. They make about 8 volts, plenty to drive a mosfet gate. > Yes, they will be slow when driving a lot of capacitance. We pay about > $1.60 each. > > This is essentially what's inside small SSRs. Which can cost half that > price!Oh, that's pretty sweet. 24uA is enough to turn on a pretty big FET in 1mS or so, not bad at all. I have some Panasonic PhotoMOS SSRs by the partial-reel but they're unsuitable here--several ohms, with no way to access the PV array.> Vishay makes a dual, 13 volts typ output. In series, that's 26! Four > make 100 volts! Must be good for something.Yup, gotta be good for something. Driving varactors without fuss or EMI, for one. Cheers, James
Reply by ●October 3, 20152015-10-03
On 10/3/2015 7:10 PM, dagmargoodboat@yahoo.com wrote:> On Saturday, October 3, 2015 at 6:09:24 PM UTC-4, rickman wrote: >> On 10/3/2015 5:57 PM, Tom Miller wrote: >>> >>> "rickman" <gnuarm@gmail.com> wrote in message >>> news:muph5o$88r$2@dont-email.me... >>>> On 10/3/2015 4:58 PM, John Larkin wrote: >>>>> On Sat, 3 Oct 2015 11:09:40 -0700 (PDT), dagmargoodboat@yahoo.com >>>>> wrote: >>>>> >>>>> >>>>> PV optocouplers are cool for driving isolated gates, but maybe not >>>>> available in your junk box. >>>>> >>>>> I'm designing a kilovolt-range linear voltage regulator, and a PV is a >>>>> really easy way to drive the pass transistor gate. >>>>> >>>>> Hey, a packaged SIP dc/dc converter would make a nice SSR gate driver. >>>>> $4 or something from Mouser. >>>> >>>> That is the point of this circuit. A PV photocoupler needs a power >>>> source. This circuit *is* the power source. >>>> >>>> >>> >>> No, a PV optocoupler makes it own voltage. Just add it to the 12 volts >>> to drive the gate. >> >> Since when? They use a phototransistor, not a PV solar cell. > > The PV couplers John and Tom are talking about actually do exactly that--they > couple an LED to a solar cell array, which drives a FET. > > They're slow, and expensive, but neat. I'm not sure if they come sufficiently > hefty to run a radiator fan, and small enough to fit in a 2 x 1 x .5" metal case > though.Yes, I see now that he used *exactly* the term PV. Sorry for that. I've never seen one before. -- Rick
Reply by ●October 3, 20152015-10-03
On Saturday, October 3, 2015 at 7:45:02 PM UTC-4, Jim Thompson wrote:> On Sat, 3 Oct 2015 11:09:40 -0700 (PDT), dagmargoodboat@yahoo.com > wrote: > > >12v automotive SSR, to replace a failed $35 unit in my car. > > > > Q3 > > | |-------+---O > > | |<-. | > > D2 .---+-------+---' |--+ .---' > > .-----. | |C1 | | / \ TVS > > .--------------------|~ +|--' |10nF .-. R4 | --- > > | T1b 500uH | | --- | | 22K | | > > '-----. . . . .------|~ -|--. --- '-' | | > > '-'-'-'-' '-----' | | | | | > > --------- '---+-------+--------+----+---O > > --------- > > .-.-.-.-. > > .------' ' | ' '-------. > > | T1a| 1mH | > > | | | > > O--------+----+----. | > > | | | | > > | .-. .-. | > > | R1 | | R2 | | | > > |10K | | 10K | | | > > | '-' '-' | > > | | ===== | | > > \| | .-.-. | |/ > > |---+--' ' '--+----| > > .<| T1c |>. > > | Q1 10uH Q2 | > > | | > > '----------+-----------' > > | > > .-. > > | | R3 > > | | 470 > > '-' > > | > > | > > LED1 V ~~> > > --- > > | > > | > > V D1 > > --- > > | > > O------------' > > > > [snip] > > How much current in the load?I don't actually know. The hypothetical load was an Acura radiator cooling fan motor, whatever that draws.> Might have some SOA problems with the > soft turn-on/turn-off??I don't think so, but I didn't check. The switching times are well under 1mS, purposely, with the gate capacitor there to intentionally slow things down. Lowering C1's value speeds the switching, if needed. Okay, I just checked the SOA on a 1.2 milliohm FET, and it looks like 100uS switching is just enough to avoid SOA up to 10A (for this random monster FET). It might need a tougher FET or slightly faster switching to be solid. Unknown, since the load is a mystery. Right now it switches Q3 'on' in 30uS (fan-start, the worst case load) and 'off' in 120uS. Not bad, but might need beefing.> Might make a Schmitt arrangement, charge up cap _then_ connect to gate > and vice versa for turn-off.Yup. Hate to use extra parts though, if avoidable. In your world parts are free. In mine they have to be bought, inventoried, and soldered. Cheers, James Arthur
Reply by ●October 3, 20152015-10-03
On 10/3/2015 8:26 PM, dagmargoodboat@yahoo.com wrote:> On Saturday, October 3, 2015 at 7:45:02 PM UTC-4, Jim Thompson wrote: >> On Sat, 3 Oct 2015 11:09:40 -0700 (PDT), dagmargoodboat@yahoo.com >> wrote: >> >>> 12v automotive SSR, to replace a failed $35 unit in my car. >>> >>> Q3 >>> | |-------+---O >>> | |<-. | >>> D2 .---+-------+---' |--+ .---' >>> .-----. | |C1 | | / \ TVS >>> .--------------------|~ +|--' |10nF .-. R4 | --- >>> | T1b 500uH | | --- | | 22K | | >>> '-----. . . . .------|~ -|--. --- '-' | | >>> '-'-'-'-' '-----' | | | | | >>> --------- '---+-------+--------+----+---O >>> --------- >>> .-.-.-.-. >>> .------' ' | ' '-------. >>> | T1a| 1mH | >>> | | | >>> O--------+----+----. | >>> | | | | >>> | .-. .-. | >>> | R1 | | R2 | | | >>> |10K | | 10K | | | >>> | '-' '-' | >>> | | ===== | | >>> \| | .-.-. | |/ >>> |---+--' ' '--+----| >>> .<| T1c |>. >>> | Q1 10uH Q2 | >>> | | >>> '----------+-----------' >>> | >>> .-. >>> | | R3 >>> | | 470 >>> '-' >>> | >>> | >>> LED1 V ~~> >>> --- >>> | >>> | >>> V D1 >>> --- >>> | >>> O------------' >>> >> >> [snip] >> >> How much current in the load? > > I don't actually know. The hypothetical load was an Acura radiator cooling > fan motor, whatever that draws. > >> Might have some SOA problems with the >> soft turn-on/turn-off?? > > I don't think so, but I didn't check. The switching times are well under 1mS, > purposely, with the gate capacitor there to intentionally slow things > down. Lowering C1's value speeds the switching, if needed. > > Okay, I just checked the SOA on a 1.2 milliohm FET, and it looks like 100uS > switching is just enough to avoid SOA up to 10A (for this random monster FET). > It might need a tougher FET or slightly faster switching to be solid. Unknown, > since the load is a mystery. > > Right now it switches Q3 'on' in 30uS (fan-start, the worst case load) and 'off' > in 120uS. Not bad, but might need beefing. > >> Might make a Schmitt arrangement, charge up cap _then_ connect to gate >> and vice versa for turn-off. > > Yup. Hate to use extra parts though, if avoidable. In your world parts are > free. In mine they have to be bought, inventoried, and soldered.If you are actually going to build this, why not use any of the many SSR devices in a package? What will this circuit do that a commercial unit won't? This looks like a much larger circuit than you could do with an SSR. The one that failed was made by who? -- Rick
Reply by ●October 3, 20152015-10-03
"rickman" <gnuarm@gmail.com> wrote in message news:mupjij$k5a$1@dont-email.me...> On 10/3/2015 5:57 PM, Tom Miller wrote: >> >> "rickman" <gnuarm@gmail.com> wrote in message >> news:muph5o$88r$2@dont-email.me... >>> On 10/3/2015 4:58 PM, John Larkin wrote: >>>> On Sat, 3 Oct 2015 11:09:40 -0700 (PDT), dagmargoodboat@yahoo.com >>>> wrote: >>>> >>>> >>>> PV optocouplers are cool for driving isolated gates, but maybe not >>>> available in your junk box. >>>> >>>> I'm designing a kilovolt-range linear voltage regulator, and a PV is a >>>> really easy way to drive the pass transistor gate. >>>> >>>> Hey, a packaged SIP dc/dc converter would make a nice SSR gate driver. >>>> $4 or something from Mouser. >>> >>> That is the point of this circuit. A PV photocoupler needs a power >>> source. This circuit *is* the power source. >>> >>> >> >> No, a PV optocoupler makes it own voltage. Just add it to the 12 volts >> to drive the gate. > > Since when? They use a phototransistor, not a PV solar cell. > > -- > > RickI guess that's why they call them PV optocouplers.
Reply by ●October 3, 20152015-10-03
On Saturday, October 3, 2015 at 2:09:48 PM UTC-4, dagmarg...@yahoo.com wrote:> 12v automotive SSR, to replace a failed $35 unit in my car. > > Q3 > | |-------+---O > | |<-. | > D2 .---+-------+---' |--+ .---' > .-----. | |C1 | | / \ TVS > .--------------------|~ +|--' |10nF .-. R4 | --- > | T1b 500uH | | --- | | 22K | | > '-----. . . . .------|~ -|--. --- '-' | | > '-'-'-'-' '-----' | | | | | > --------- '---+-------+--------+----+---O > --------- > .-.-.-.-. > .------' ' | ' '-------. > | T1a| 1mH | > | | | > O--------+----+----. | > | | | | > | .-. .-. | > | R1 | | R2 | | | > |10K | | 10K | | | > | '-' '-' | > | | ===== | | > \| | .-.-. | |/ > |---+--' ' '--+----| > .<| T1c |>. > | Q1 10uH Q2 | > | | > '----------+-----------' > | > .-. > | | R3 > | | 470 > '-' > | > | > LED1 V ~~> > --- > | > | > V D1 > --- > | > O------------' > > Cheers, > James Arthur > ---- > > Version 4 > SHEET 1 984 680 > WIRE 880 -144 816 -144 > WIRE 352 -64 208 -64 > WIRE 368 -64 352 -64 > WIRE 464 -64 432 -64 > WIRE 656 -64 464 -64 > WIRE 704 -64 656 -64 > WIRE 768 -64 704 -64 > WIRE 352 -48 352 -64 > WIRE 464 -48 464 -64 > WIRE 656 -48 656 -64 > WIRE 704 -48 704 -64 > WIRE 880 -48 880 -144 > WIRE 880 -48 816 -48 > WIRE 208 32 208 -64 > WIRE 352 32 352 16 > WIRE 352 32 288 32 > WIRE 368 32 352 32 > WIRE 464 32 464 16 > WIRE 464 32 432 32 > WIRE 816 48 816 -48 > WIRE 464 64 464 32 > WIRE 656 64 656 16 > WIRE 704 64 704 32 > WIRE 160 128 80 128 > WIRE 256 128 240 128 > WIRE 272 128 256 128 > WIRE 416 128 352 128 > WIRE -176 176 -224 176 > WIRE -48 176 -112 176 > WIRE 176 176 16 176 > WIRE 256 176 256 128 > WIRE 256 176 176 176 > WIRE 320 176 256 176 > WIRE 176 208 176 176 > WIRE 320 208 320 176 > WIRE -224 224 -224 176 > WIRE 80 256 80 128 > WIRE 416 256 416 128 > WIRE 176 304 176 288 > WIRE 176 304 144 304 > WIRE 208 304 176 304 > WIRE 320 304 320 288 > WIRE 320 304 288 304 > WIRE 352 304 320 304 > WIRE -224 336 -224 304 > WIRE 80 384 80 352 > WIRE 256 384 80 384 > WIRE 416 384 416 352 > WIRE 416 384 256 384 > WIRE 256 400 256 384 > WIRE 256 496 256 480 > FLAG 256 496 0 > FLAG -224 336 0 > FLAG 464 64 0 > FLAG 656 64 0 > FLAG 704 64 0 > FLAG 816 48 0 > SYMBOL ind2 144 144 R270 > WINDOW 0 32 56 VTop 2 > WINDOW 3 5 56 VBottom 2 > SYMATTR InstName L1 > SYMATTR Value 500�H > SYMATTR Type ind > SYMBOL ind2 256 144 R270 > WINDOW 0 32 56 VTop 2 > WINDOW 3 5 56 VBottom 2 > SYMATTR InstName L2 > SYMATTR Value 500�H > SYMATTR Type ind > SYMBOL ind2 304 16 R90 > WINDOW 0 5 56 VBottom 2 > WINDOW 3 32 56 VTop 2 > SYMATTR InstName L3 > SYMATTR Value 500�H > SYMATTR Type ind > SYMBOL npn 352 256 R0 > SYMATTR InstName Q1 > SYMATTR Value 2N3904 > SYMBOL npn 144 256 M0 > SYMATTR InstName Q2 > SYMATTR Value 2N3904 > SYMBOL res 160 192 R0 > SYMATTR InstName R1 > SYMATTR Value 10K > SYMBOL res 240 384 R0 > SYMATTR InstName R2 > SYMATTR Value 470 > SYMBOL ind2 304 288 R90 > WINDOW 0 5 56 VBottom 2 > WINDOW 3 32 56 VTop 2 > SYMATTR InstName L4 > SYMATTR Value 10�H > SYMATTR Type ind > SYMBOL res 304 192 R0 > SYMATTR InstName R3 > SYMATTR Value 10K > SYMBOL voltage -224 208 R0 > WINDOW 123 0 0 Left 2 > WINDOW 39 0 0 Left 2 > SYMATTR InstName V1 > SYMATTR Value PULSE(0 12 0 0 0 5mS) > SYMBOL diode 368 -48 R270 > WINDOW 0 32 32 VTop 2 > WINDOW 3 0 32 VBottom 2 > SYMATTR InstName D1 > SYMATTR Value 1N4148 > SYMBOL nmos 768 -144 R0 > SYMATTR InstName M1 > SYMATTR Value AP9465GEM > SYMBOL cap 640 -48 R0 > WINDOW 0 -38 41 Left 2 > WINDOW 3 -33 66 Left 2 > SYMATTR InstName C1 > SYMATTR Value 10nF > SYMBOL res 688 -64 R0 > SYMATTR InstName R4 > SYMATTR Value 22k > SYMBOL diode 432 16 R90 > WINDOW 0 0 32 VBottom 2 > WINDOW 3 32 32 VTop 2 > SYMATTR InstName D2 > SYMATTR Value 1N4148 > SYMBOL diode 368 16 R180 > WINDOW 0 24 64 Left 2 > WINDOW 3 24 0 Left 2 > SYMATTR InstName D3 > SYMATTR Value 1N4148 > SYMBOL diode 480 16 R180 > WINDOW 0 24 64 Left 2 > WINDOW 3 24 0 Left 2 > SYMATTR InstName D4 > SYMATTR Value 1N4148 > SYMBOL LED -176 192 R270 > WINDOW 0 32 32 VTop 2 > WINDOW 3 0 32 VBottom 2 > SYMATTR InstName D5 > SYMATTR Value QTLP690C > SYMATTR Description Diode > SYMATTR Type diode > SYMBOL diode -48 192 R270 > WINDOW 0 32 32 VTop 2 > WINDOW 3 0 32 VBottom 2 > SYMATTR InstName D6 > SYMATTR Value 1N4148 > TEXT 512 240 Left 2 !K1 L1 L2 L3 L4 1. > TEXT 536 296 Left 2 !.tran 10mS > TEXT 520 168 Left 2 ;29-Sep-2015 by jdaThere's an oscillator (I think) in the diff pair transformer part but I'm not seeing it. (At home, I don't have ltspice here.. well other machine.) George H.
Reply by ●October 3, 20152015-10-03
On Saturday, October 3, 2015 at 8:37:48 PM UTC-4, rickman wrote:> On 10/3/2015 8:26 PM, dagmargoodboat@yahoo.com wrote: > > On Saturday, October 3, 2015 at 7:45:02 PM UTC-4, Jim Thompson wrote: > >> On Sat, 3 Oct 2015 11:09:40 -0700 (PDT), dagmargoodboat@yahoo.com > >> wrote: > >> > >>> 12v automotive SSR, to replace a failed $35 unit in my car. > >>> > >>> Q3 > >>> | |-------+---O > >>> | |<-. | > >>> D2 .---+-------+---' |--+ .---' > >>> .-----. | |C1 | | / \ TVS > >>> .--------------------|~ +|--' |10nF .-. R4 | --- > >>> | T1b 500uH | | --- | | 22K | | > >>> '-----. . . . .------|~ -|--. --- '-' | | > >>> '-'-'-'-' '-----' | | | | | > >>> --------- '---+-------+--------+----+---O > >>> --------- > >>> .-.-.-.-. > >>> .------' ' | ' '-------. > >>> | T1a| 1mH | > >>> | | | > >>> O--------+----+----. | > >>> | | | | > >>> | .-. .-. | > >>> | R1 | | R2 | | | > >>> |10K | | 10K | | | > >>> | '-' '-' | > >>> | | ===== | | > >>> \| | .-.-. | |/ > >>> |---+--' ' '--+----| > >>> .<| T1c |>. > >>> | Q1 10uH Q2 | > >>> | | > >>> '----------+-----------' > >>> | > >>> .-. > >>> | | R3 > >>> | | 470 > >>> '-' > >>> | > >>> | > >>> LED1 V ~~> > >>> --- > >>> | > >>> | > >>> V D1 > >>> --- > >>> | > >>> O------------' > >>> > >> > >> [snip] > >> > >> How much current in the load? > > > > I don't actually know. The hypothetical load was an Acura radiator cooling > > fan motor, whatever that draws. > > > >> Might have some SOA problems with the > >> soft turn-on/turn-off?? > > > > I don't think so, but I didn't check. The switching times are well under 1mS, > > purposely, with the gate capacitor there to intentionally slow things > > down. Lowering C1's value speeds the switching, if needed. > > > > Okay, I just checked the SOA on a 1.2 milliohm FET, and it looks like 100uS > > switching is just enough to avoid SOA up to 10A (for this random monster FET). > > It might need a tougher FET or slightly faster switching to be solid. Unknown, > > since the load is a mystery. > > > > Right now it switches Q3 'on' in 30uS (fan-start, the worst case load) and 'off' > > in 120uS. Not bad, but might need beefing. > > > >> Might make a Schmitt arrangement, charge up cap _then_ connect to gate > >> and vice versa for turn-off. > > > > Yup. Hate to use extra parts though, if avoidable. In your world parts are > > free. In mine they have to be bought, inventoried, and soldered. > > If you are actually going to build this,I'm not building it, that's why it's a very silly circuit. I already swapped in a spare relay from an unused accessory. This was just for fun, to see what it might take.> why not use any of the many SSR > devices in a package? What will this circuit do that a commercial unit > won't? This looks like a much larger circuit than you could do with an > SSR.Will it fit in a ~2 x 1 x .5" package, to fit in the original space?> > The one that failed was made by who?It wasn't marked. It lasted almost thirty years bolted onto an automobile's radiator bracket, so I have absolutely no complaints. Failed with coil open. Cheers, James Arthur
Reply by ●October 3, 20152015-10-03
On Sunday, 4 October 2015 00:02:59 UTC+1, dagmarg...@yahoo.com wrote:> The radiator cooling fan is the one that failed. The swapped-relay works, but I > won't know until summer if the temp sensor driving its coil is good. :-) > > Cheers, > JamesIn many places cars are fine with a permanently dead rad fan. NT
Reply by ●October 3, 20152015-10-03
On Saturday, October 3, 2015 at 8:47:46 PM UTC-4, George Herold wrote:> On Saturday, October 3, 2015 at 2:09:48 PM UTC-4, dagmarg...@yahoo.com wrote: > > 12v automotive SSR, to replace a failed $35 unit in my car. > > > > Q3 > > | |-------+---O > > | |<-. | > > D2 .---+-------+---' |--+ .---' > > .-----. | |C1 | | / \ TVS > > .--------------------|~ +|--' |10nF .-. R4 | --- > > | T1b 500uH | | --- | | 22K | | > > '-----. . . . .------|~ -|--. --- '-' | | > > '-'-'-'-' '-----' | | | | | > > --------- '---+-------+--------+----+---O > > --------- > > .-.-.-.-. > > .------' ' | ' '-------. > > | T1a| 1mH | > > | | | > > O--------+----+----. | > > | | | | > > | .-. .-. | > > | R1 | | R2 | | | > > |10K | | 10K | | | > > | '-' '-' | > > | | ===== | | > > \| | .-.-. | |/ > > |---+--' ' '--+----| > > .<| T1c |>. > > | Q1 10uH Q2 | > > | | > > '----------+-----------' > > | > > .-. > > | | R3 > > | | 470 > > '-' > > | > > | > > LED1 V ~~> > > --- > > | > > | > > V D1 > > --- > > | > > O------------' > > > > Cheers, > > James Arthur[...]> There's an oscillator (I think) in the diff pair > transformer part but I'm not seeing it. > > (At home, I don't have ltspice here.. well other machine.)The biasing biases both transistors linear, and the base drive from T1c guarantees positive feedback. Oscillation ensues. The quasi-diff pair makes a modified blocking oscillator, but with a defined current-limited drive into the transformer, instead of relying on Q1-Q2 characteristics to set that. It's set to use 20mA, mostly to power the indicator LED. Cheers, James Arthur
