tiscando
05-06-2009, 18:17
Hi,
While I was working on the virtual circuit of a frequency controlled delay, up from the version in the 'too many iterations without convergence' thread, with the latter post talking about a simulation fault with the charge pump (frequency to voltage).
I was looking up 'proper' voltage (or current) controlled resistors, and most of the results talk about the use of the Jfet, which I found to not be bidirectional. Next, I found an analog optocoupler on Rapidonline (http://www.rapidonline.com/Electronic-Components/Optoelectronics/Photocouplers/Axial-analogue-optical-isolator/80338), which suits my application well. However, there's no model of it on picaxe VSM.
I've created a sub-circuit which uses an arbitary ccvs linked to a voltage controlled resistor to mimics this analog opto-isolator / opto-coupler.
I was creating a formula in the excel spreadsheet with a logarithmic graph to help me match it with the VTL5C6 current vs resistance graph in this datasheet on rapidonline (http://www.rapidonline.com/netalogue/specs/58-0146.pdf). Then, I copied this formula into the arbitary model's formula field, and validated it so it is ((100/(((I(A,B)*1000)^1.4)+0.001))+2.2)/10000. The extra /10000mV is added so the voltages are more in range with the simulator. After this, I thoroughly tested it with the test circuit.
The settings for the voltage controlled resistor in the sub (does the Min and Max parts):
- On voltage: 10
- On resistance: 100M
- Off voltage: 0.000275
- Off resistance: 2.75k
Here, I've attached a compound diagram to show users what it looks like, before downloading the .dsn file which comprises of the VTL5C6 sub-circuit, and a test circuit around it (including my resistance meter!)
The LED is in the subcircuit to sustain the LED effects on the input (forward voltage drop...).
I have not included the time delay to reach 100M ohms @ 0mA yet.
The formula which creates the graph is =((100/((B1^1.4)+0.001))+2.2).
p.s. I have spent a long time to find the right graph and it's right settings to make a XY logarithmic graph. To do this, you need to choose the scatter graph (with line) as both axis are values, and can be configured to be logarithmic.
While I was working on the virtual circuit of a frequency controlled delay, up from the version in the 'too many iterations without convergence' thread, with the latter post talking about a simulation fault with the charge pump (frequency to voltage).
I was looking up 'proper' voltage (or current) controlled resistors, and most of the results talk about the use of the Jfet, which I found to not be bidirectional. Next, I found an analog optocoupler on Rapidonline (http://www.rapidonline.com/Electronic-Components/Optoelectronics/Photocouplers/Axial-analogue-optical-isolator/80338), which suits my application well. However, there's no model of it on picaxe VSM.
I've created a sub-circuit which uses an arbitary ccvs linked to a voltage controlled resistor to mimics this analog opto-isolator / opto-coupler.
I was creating a formula in the excel spreadsheet with a logarithmic graph to help me match it with the VTL5C6 current vs resistance graph in this datasheet on rapidonline (http://www.rapidonline.com/netalogue/specs/58-0146.pdf). Then, I copied this formula into the arbitary model's formula field, and validated it so it is ((100/(((I(A,B)*1000)^1.4)+0.001))+2.2)/10000. The extra /10000mV is added so the voltages are more in range with the simulator. After this, I thoroughly tested it with the test circuit.
The settings for the voltage controlled resistor in the sub (does the Min and Max parts):
- On voltage: 10
- On resistance: 100M
- Off voltage: 0.000275
- Off resistance: 2.75k
Here, I've attached a compound diagram to show users what it looks like, before downloading the .dsn file which comprises of the VTL5C6 sub-circuit, and a test circuit around it (including my resistance meter!)
The LED is in the subcircuit to sustain the LED effects on the input (forward voltage drop...).
I have not included the time delay to reach 100M ohms @ 0mA yet.
The formula which creates the graph is =((100/((B1^1.4)+0.001))+2.2).
p.s. I have spent a long time to find the right graph and it's right settings to make a XY logarithmic graph. To do this, you need to choose the scatter graph (with line) as both axis are values, and can be configured to be logarithmic.