Qspice flashing error for BJT Model file

QSPICE
1

Hi I’m simulating ZETEX FZT653 Spice Model v1.0 Last Revised 18/3/97 Model. getting error
Fatal error: Either both of Von and Voff or Vt and Vh must be specified for switch instance SUPPLY or model S.
The model that i have used is :

*ZETEX FZT653 Spice Model v1.0 Last Revised 18/3/97
*
.MODEL FZT653 NPN IS =3.8206E-13 NF =1.0025 BF =250 IKF=1.15 VAF=154
+ ISE=1.035E-13 NE =1.3642 NR =1.0012 BR =50 IKR=0.42 VAR=38
+ ISC=7E-13 NC =1.19 RB =0.04 RE =0.0875 RC =0.06
+ CJC=45.5E-12 MJC=0.4534 VJC=0.5774 CJE=278E-12
+ TF =0.78E-9 TR =30E-9
*
*$
*

Please let me know if i may need to change anything.

2

This error should related to how you define the Switch model. Can you upload your schematic?

3

Unfortunately I cannot upload the schematic design.
It is used in power supply conversion.

4

Depending on your circuit complexity, you can share the schematic netlist using the following steps before you can upload file in this forum:

  1. In Qspice, go to View > Netlist.
  2. In the netlist window, right-click and select all, then right-click and copy.
  3. In the forum message box, create a new line, press Ctrl-E for preformatted text, and paste your netlist in the “type or paste code here” section.

** Do not paste the text without using preformatted text, as this forum may automatically change the format of certain expressions.

5

Fatal error: Either both of Von and Voff or Vt and Vh must be specified for switch instance SUPPLY or model S.

What are these parameters Von, Voff , Vt and Vh ??

6

Here is how to define a Switch for use. The .model method is commonly known by LTspice users. Qspice also offers the Instance parameters method. I have attached a custom symbol for the Instance parameter method.

Switch-InstanceParam.qsym (1.2 KB)

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image1868×1010 227 KB

7

Yes this I understood and I used this in Ltspice. Since that was BJT and I think some of its parameter were not read by qspice. Even I tried to add Vh and Vt in the text file still it shows some error.
And yeah thank you for this switch explaination, I’ll try to use this as well.

8

I loaded your FZT653 model into Qspice and everything works fine with a DC analysis. The error you described should relate to the Switch device. In Qspice, the Switch model must include Vh (as Vh doesn’t have default value). Users transitioning from LTspice to Qspice may overlook the need for Vh in the Switch model, as Vh has a default value 0 in LTspice.

BJT-FZT653.qsch (3.1 KB)

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image1277×441 38.7 KB

9

Okay. Thank You So Much for this :slightly_smiling_face: