Analog Push-On / Hold-Off switch circuit
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Look at the .tran directive. I tried startup, and commented it out, when it made nodifference.
From: LTspice@groups.io <LTspice@groups.io> On Behalf Of
eetech00 via groups.io
Sent: Sunday, October 20, 2024 12:07 PM To: LTspice@groups.io Subject: EXTERNAL: Re: [LTspice] Analog Push-On / Hold-Off switch circuit
On Sun, Oct 20, 2024 at 10:25 AM, Bell, Dave wrote:
Circuit looks ok to me.
Just add "startup" to the .trans statement and delay the first button press so its easier to see initialization. The circuit will start in OFF state.
If you don't use startup. you'll have to manually initialize various nodes.
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Oh, hell, I give up! *After* my reply, I went back and uncommented the startup option, and now it works correctly! Some other tweak I put in seems to have fixed it.
Thanks for the push-back!
From: LTspice@groups.io <LTspice@groups.io> On Behalf Of
Bell, Dave (US)
Sent: Sunday, October 20, 2024 1:16 PM To: LTspice@groups.io Subject: EXTERNAL: Re: [LTspice] Analog Push-On / Hold-Off switch circuit
Look at the .tran directive. I tried startup, and commented it out, when it made nodifference.
From: LTspice@groups.io <LTspice@groups.io>
On Behalf Of eetech00 via groups.io
On Sun, Oct 20, 2024 at 10:25 AM, Bell, Dave wrote:
Circuit looks ok to me.
Just add "startup" to the .trans statement and delay the first button press so its easier to see initialization. The circuit will start in OFF state.
If you don't use startup. you'll have to manually initialize various nodes.
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Well, almost. The first (long) push actually turns it on, then off again, after ~800ms.
From: LTspice@groups.io <LTspice@groups.io> On Behalf Of
Bell, Dave (US)
Sent: Sunday, October 20, 2024 1:19 PM To: LTspice@groups.io Subject: EXTERNAL: Re: [LTspice] Analog Push-On / Hold-Off switch circuit
Oh, hell, I give up! *After* my reply, I went back and uncommented the startup option, and now it works correctly! Some other tweak I put in seems to have fixed it.
Thanks for the push-back!
From: LTspice@groups.io <LTspice@groups.io>
On Behalf Of Bell, Dave (US)
Look at the .tran directive. I tried startup, and commented it out, when it made nodifference.
From: LTspice@groups.io <LTspice@groups.io>
On Behalf Of eetech00 via groups.io
On Sun, Oct 20, 2024 at 10:25 AM, Bell, Dave wrote:
Circuit looks ok to me.
Just add "startup" to the .trans statement and delay the first button press so its easier to see initialization. The circuit will start in OFF state.
If you don't use startup. you'll have to manually initialize various nodes.
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If you are using the Infineon model for the IRLML6402 (Q1) and run the simulation at 20 volts, the circuit will switch on even with the startup option. The reason is the IRLML6402 model includes the drain-source diode that has a 20v breakdown:
D1 1 3 MD
.MODEL MD D IS=2.03395e-08 RS=0.0432758 N=1.5 BV=20 +IBV=0.00025 EG=1 XTI=4 TT=1e-07 +CJO=1.11974e-10 VJ=0.5 M=0.3 FC=0.5 Solution: Use a ZXMP3A16G instead. It's a 30-volt device with a Vgsmax=+/-20v and a Vgs(th) of -1v minimum.
There are other problems that I've found and hope to submit a Design Idea correcting them.
John
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Bell, Dave
John Waugaman