Re: P-channel MOSFET model

On 9/05/2024 6:13 am, piglet wrote:

Bill Sloman <bill.sloman@ieee.org> wrote:

On 8/05/2024 10:03 pm, piglet wrote:

On 06/05/2024 06:58, Edward Rawde wrote:

"John Larkin" <jjSNIPlarkin@highNONOlandtechnology.com> wrote in message
news:aesf3j1po3glh1c23se3lofoni6j7ol75m@4ax.com...

On Sun, 5 May 2024 14:42:30 -0400, "Edward Rawde" <invalid@invalid.invalid> wrote:

"Edward Rawde" <invalid@invalid.invalid> wrote in message
news:v16s2i$2uv4$1@nnrp.usenet.blueworldhosting.com...

Does anyone know of a P-channel MOSFET, roughly equivalent to

>
<snip>
>
Cutting and pasting piglet's .asc file into my version of LTSpice gave a
circuit that didn't do anything useful. M1 turns off after 2.67usec.,
and that's it.
>

 Damn! You are right, some thing strange happened with L1 value. The mu
symbol comes out wrong on a second system. Either retype as 220u or as
0.22m and see if that works better?

Switching to 220u did solve the problem. I should have noticed.
Radiating 150kHz from a remote lamp isn't great idea.
This variation on the circuit slows the switching to 16kHz, but doesn't do anything for the amplitude. Some gain along the feedback path would cut the reduce the current excursions through D2 and the radiated noise.
Replacing Q2 with an LM358 might do it.
Version 4
SHEET 1 1340 680
WIRE 64 -112 -144 -112
WIRE 256 -112 64 -112
WIRE 496 -112 256 -112
WIRE 1008 -112 496 -112
WIRE 1008 -96 1008 -112
WIRE 64 -32 64 -112
WIRE 1008 16 1008 -16
WIRE 1008 16 128 16
WIRE 256 64 256 -112
WIRE 64 96 64 64
WIRE 496 96 496 -112
WIRE 1008 96 1008 16
WIRE -144 144 -144 -112
WIRE 64 192 64 176
WIRE 128 192 64 192
WIRE 496 192 496 160
WIRE 496 192 208 192
WIRE 496 224 496 192
WIRE 544 224 496 224
WIRE 656 224 624 224
WIRE 736 224 720 224
WIRE 752 224 736 224
WIRE 864 224 816 224
WIRE 880 224 864 224
WIRE 1008 224 1008 160
WIRE 1008 224 944 224
WIRE 496 240 496 224
WIRE 256 320 256 144
WIRE 448 320 256 320
WIRE 736 320 736 224
WIRE 864 320 864 224
WIRE 1008 320 1008 224
WIRE 256 336 256 320
WIRE 64 384 64 192
WIRE 192 384 64 384
WIRE 64 400 64 384
WIRE -144 496 -144 224
WIRE 64 496 64 480
WIRE 64 496 -144 496
WIRE 256 496 256 432
WIRE 256 496 64 496
WIRE 496 496 496 336
WIRE 496 496 256 496
WIRE 736 496 736 384
WIRE 736 496 496 496
WIRE 864 496 864 384
WIRE 864 496 736 496
WIRE 1008 496 1008 384
WIRE 1008 496 864 496
WIRE -144 560 -144 496
FLAG -144 560 0
SYMBOL voltage -144 128 R0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V1
SYMATTR Value 12
SYMBOL nmos 448 240 R0
SYMATTR InstName M1
SYMATTR Value FDS6612A
SYMBOL schottky 512 160 R180
WINDOW 0 24 64 Left 2
WINDOW 3 24 0 Left 2
SYMATTR InstName D1
SYMATTR Value 1N5817
SYMATTR Description Diode
SYMATTR Type diode
SYMBOL ind 640 208 R90
WINDOW 0 5 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName L1
SYMATTR Value 220µ
SYMATTR SpiceLine Cpar=1p
SYMBOL LED 992 96 R0
SYMATTR InstName D2
SYMATTR Value LXK2-PW14
SYMATTR Description Diode
SYMATTR Type diode
SYMBOL res 1008 -64 R0
SYMATTR InstName R5
SYMATTR Value 1.2
SYMBOL res 256 96 R0
SYMATTR InstName R4
SYMATTR Value 3k
SYMBOL pnp 128 64 R180
SYMATTR InstName Q1
SYMATTR Value 2N3906
SYMBOL res 64 432 R0
SYMATTR InstName R2
SYMATTR Value 3k
SYMBOL res 176 192 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R3
SYMATTR Value 62k
SYMBOL npn 192 336 R0
SYMATTR InstName Q2
SYMATTR Value 2N3904
SYMBOL res 64 128 R0
SYMATTR InstName R1
SYMATTR Value 3k
SYMBOL FerriteBead 688 224 R90
WINDOW 0 -16 0 VBottom 2
SYMATTR InstName L2
SYMATTR Value 14µ
SYMATTR SpiceLine Ipk=3 Rser=0.0122 Rpar=870 Cpar=1000f
SYMBOL polcap 992 320 R0
WINDOW 3 24 56 Left 2
SYMATTR InstName C1
SYMATTR Value 22µ
SYMATTR Description Capacitor
SYMATTR Type cap
SYMATTR SpiceLine V=16 Irms=0 Rser=1.6 Lser=0 mfg="AVX" pn="TAJC226K016" type="Tantalum"
SYMBOL FerriteBead 784 224 R90
WINDOW 0 -16 0 VBottom 2
SYMATTR InstName L3
SYMATTR Value 14µ
SYMATTR SpiceLine Ipk=3 Rser=0.0122 Rpar=870 Cpar=1000f
SYMBOL polcap 720 320 R0
WINDOW 3 24 56 Left 2
SYMATTR InstName C2
SYMATTR Value 22µ
SYMATTR Description Capacitor
SYMATTR Type cap
SYMATTR SpiceLine V=16 Irms=0 Rser=1.6 Lser=0 mfg="AVX" pn="TAJC226K016" type="Tantalum"
SYMBOL FerriteBead 912 224 R90
WINDOW 0 -16 0 VBottom 2
SYMATTR InstName L4
SYMATTR Value 14µ
SYMATTR SpiceLine Ipk=3 Rser=0.0122 Rpar=870 Cpar=1000f
SYMBOL polcap 848 320 R0
WINDOW 3 24 56 Left 2
SYMATTR InstName C3
SYMATTR Value 22µ
SYMATTR Description Capacitor
SYMATTR Type cap
SYMATTR SpiceLine V=16 Irms=0 Rser=1.6 Lser=0 mfg="AVX" pn="TAJC226K016" type="Tantalum"
TEXT 736 560 Left 2 !.tran 10m
TEXT 1112 232 Left 2 ;EPW SED May 2024
TEXT 1072 280 Left 2 ;Simple LED buck smps
--
Bill Sloman, Sydney