Copy of Transient Stability Testing of Transmission Line Fed LED Driver - on Thu, 07/04/2024 - 09:59 Designer257254 × Member for 10 months 4 weeks 8 designs 1 groups Welcome to the community!! https://explore.partquest.com/node/661367 <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/661367"></iframe> Title Description <p>This is a companion example to the design: "TDFS Impedance Stability of Transmission Line Fed LED Driver - Switching". In this version, a switch is added to turn on two of the LEDs after 2 ms, to inject a load transient into the system. This transient will expose the severity of the damped ringing response at the converter input, or system instability if the source/load impedance ratio is inadequate.</p> <p>The initial configuration for this design uses a cable length of 400 meters with 8 AWG = 2.1 mOhm/meter conductors, and a converter input capacitor = 22uF. This is consistent with the companion design. You can try using an increased cable length (e.g. 800 meters, 5 AWG = 1 mOhm/meter) by making a copy of this design and re-running the simulation. You will see that the circuit becomes unstable at that longer length. You can also try larger values of input capacitance, to mitigate the instability problem.</p> About text formats Tags Buck ConverterConstant Power LoadsSwitching ConverterLEDtransmission lineStep-DownTDFS Impedance Stability Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None -
Copy of Transient Stability Testing of Transmission Line Fed LED Driver - on Thu, 07/04/2024 - 09:53 Designer257254 × Member for 10 months 4 weeks 8 designs 1 groups Welcome to the community!! https://explore.partquest.com/node/661366 <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/661366"></iframe> Title Description <p>This is a companion example to the design: "TDFS Impedance Stability of Transmission Line Fed LED Driver - Switching". In this version, a switch is added to turn on two of the LEDs after 2 ms, to inject a load transient into the system. This transient will expose the severity of the damped ringing response at the converter input, or system instability if the source/load impedance ratio is inadequate.</p> <p>The initial configuration for this design uses a cable length of 400 meters with 8 AWG = 2.1 mOhm/meter conductors, and a converter input capacitor = 22uF. This is consistent with the companion design. You can try using an increased cable length (e.g. 800 meters, 5 AWG = 1 mOhm/meter) by making a copy of this design and re-running the simulation. You will see that the circuit becomes unstable at that longer length. You can also try larger values of input capacitance, to mitigate the instability problem.</p> About text formats Tags Buck ConverterConstant Power LoadsSwitching ConverterLEDtransmission lineStep-DownTDFS Impedance Stability Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None -
Copy of Joule Thief Transformer Physical Design For LED Lighting - on Thu, 07/04/2024 - 09:42 Designer257254 × Member for 10 months 4 weeks 8 designs 1 groups Welcome to the community!! https://explore.partquest.com/node/661361 <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/661361"></iframe> Title Description <p>This simple "Joule Thief" self-oscillating LED circuit will produce light even when the battery voltage drops to 0.4 V. Of course the light will dim as the voltage drops, since there is no current regulation. The design is based on an example circuit from Wikipedia: https://en.wikipedia.org/wiki/Joule_thief</p> <p>For the transformer physical design, the user can explore different magnetic toroid core sizes, material types, number of winding turns, etc., to see their impact on the LED performance. This "virtual design" test-bench is particularly useful to view core saturation and its current limiting affect in this particular circuit. For example, try using a smaller core with 1/5th the area and length of the original.</p> About text formats Tags Joule ThiefLEDoscilatortransformer saturation Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None -
Copy of Transient Stability Testing of Transmission Line Fed LED Driver - on Mon, 06/03/2024 - 08:28 Designer256491 × Member for 1 year 7 designs 1 groups ¡¡¡Bienvenido a la comunidad!!! https://explore.partquest.com/node/659035 <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/659035"></iframe> Title Description <p>This is a companion example to the design: "TDFS Impedance Stability of Transmission Line Fed LED Driver - Switching". In this version, a switch is added to turn on two of the LEDs after 2 ms, to inject a load transient into the system. This transient will expose the severity of the damped ringing response at the converter input, or system instability if the source/load impedance ratio is inadequate.</p> <p>The initial configuration for this design uses a cable length of 400 meters with 8 AWG = 2.1 mOhm/meter conductors, and a converter input capacitor = 22uF. This is consistent with the companion design. You can try using an increased cable length (e.g. 800 meters, 5 AWG = 1 mOhm/meter) by making a copy of this design and re-running the simulation. You will see that the circuit becomes unstable at that longer length. You can also try larger values of input capacitance, to mitigate the instability problem.</p> About text formats Tags Buck ConverterConstant Power LoadsSwitching ConverterLEDtransmission lineStep-DownTDFS Impedance Stability Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None -
Copy of Transient Stability Testing of Transmission Line Fed LED Driver - on Mon, 06/03/2024 - 08:28 Designer256491 × Member for 1 year 7 designs 1 groups ¡¡¡Bienvenido a la comunidad!!! https://explore.partquest.com/node/659035 <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/659035"></iframe> Title Description <p>This is a companion example to the design: "TDFS Impedance Stability of Transmission Line Fed LED Driver - Switching". In this version, a switch is added to turn on two of the LEDs after 2 ms, to inject a load transient into the system. This transient will expose the severity of the damped ringing response at the converter input, or system instability if the source/load impedance ratio is inadequate.</p> <p>The initial configuration for this design uses a cable length of 400 meters with 8 AWG = 2.1 mOhm/meter conductors, and a converter input capacitor = 22uF. This is consistent with the companion design. You can try using an increased cable length (e.g. 800 meters, 5 AWG = 1 mOhm/meter) by making a copy of this design and re-running the simulation. You will see that the circuit becomes unstable at that longer length. You can also try larger values of input capacitance, to mitigate the instability problem.</p> About text formats Tags Buck ConverterConstant Power LoadsSwitching ConverterLEDtransmission lineStep-DownTDFS Impedance Stability Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None -
Copy of LED Dimmer Circuit using 555 Timer - on Wed, 05/22/2024 - 12:41 Designer256518 × Member for 1 year 1 designs 1 groups Welcome to the community!! https://explore.partquest.com/node/654189 <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/654189"></iframe> Title Description <p>This LED Dimmer Circuit uses a 555 Timer to control the PWM duty cycle of the current drive. Rather than apply proportional but continuous current to the LED for dimming, which can cause color shifts, modulating the duty cycle allows the LED to operate at its nominal current during the “ON” portion of the cycle. Because the frequency response of human vision is limited, using a PWM frequency of 250 Hz avoids the perception of flicker for the observer.</p> <p>The LED model has an internal monitor for the "perceived" light output (blue waveform), which is a low-pass filtered version of the instantaneous light output. The filter pole frequency is set to 15 Hz to represent the bandwidth of the human eye. The value of the dimmer setting (green waveform) is increased from 10% to 90% at time 100msec. The LED current pulses (red waveform) are shown before and after the duty-cycle transition.</p> <p>Part of this design is based on a dimmer schematic found on-line:</p> <p><a href="http://www.555-timer-circuits.com/led-dimmer.html">http://www.555-timer-circuits.com/led-dimmer.html</a></p> <p>That original circuit is actually incorrect, one of the diodes connected to pin 7 on the 555-Timer needs to be reversed. There was a comment from a reader who said he built the circuit as shown and it didn’t work. This is a good example of the value of simulating circuits before building hardware!</p> About text formats Tags 555 TimerLEDpotentiometer Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None -
Copy of Joule Thief Transformer Physical Design For LED Lighting - on Mon, 04/29/2024 - 11:15 Designer256107 × Member for 1 year 1 month 1 designs 1 groups Welcome to the community!! https://explore.partquest.com/node/648952 <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/648952"></iframe> Title Description <p>This simple "Joule Thief" self-oscillating LED circuit will produce light even when the battery voltage drops to 0.4 V. Of course the light will dim as the voltage drops, since there is no current regulation. The design is based on an example circuit from Wikipedia: https://en.wikipedia.org/wiki/Joule_thief</p> <p>For the transformer physical design, the user can explore different magnetic toroid core sizes, material types, number of winding turns, etc., to see their impact on the LED performance. This "virtual design" test-bench is particularly useful to view core saturation and its current limiting affect in this particular circuit. For example, try using a smaller core with 1/5th the area and length of the original.</p> About text formats Tags Joule ThiefLEDoscilatortransformer saturation Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None -
Copy of LED Dimmer Circuit using 555 Timer - on Tue, 02/27/2024 - 16:26 Designer254499 × Member for 1 year 3 months 3 designs 1 groups Welcome to the community!! https://explore.partquest.com/node/638259 <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/638259"></iframe> Title Description <p>This LED Dimmer Circuit uses a 555 Timer to control the PWM duty cycle of the current drive. Rather than apply proportional but continuous current to the LED for dimming, which can cause color shifts, modulating the duty cycle allows the LED to operate at its nominal current during the “ON” portion of the cycle. Because the frequency response of human vision is limited, using a PWM frequency of 250 Hz avoids the perception of flicker for the observer.</p> <p>The LED model has an internal monitor for the "perceived" light output (blue waveform), which is a low-pass filtered version of the instantaneous light output. The filter pole frequency is set to 15 Hz to represent the bandwidth of the human eye. The value of the dimmer setting (green waveform) is increased from 10% to 90% at time 100msec. The LED current pulses (red waveform) are shown before and after the duty-cycle transition.</p> <p>Part of this design is based on a dimmer schematic found on-line:</p> <p><a href="http://www.555-timer-circuits.com/led-dimmer.html">http://www.555-timer-circuits.com/led-dimmer.html</a></p> <p>That original circuit is actually incorrect, one of the diodes connected to pin 7 on the 555-Timer needs to be reversed. There was a comment from a reader who said he built the circuit as shown and it didn’t work. This is a good example of the value of simulating circuits before building hardware!</p> About text formats Tags 555 TimerLEDpotentiometer Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None -
Copy of LED Dimmer Circuit using 555 Timer - on Sun, 01/14/2024 - 13:52 Designer253181 × Member for 1 year 4 months 0 designs 1 groups Welcome to the community!! https://explore.partquest.com/node/630227 <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/630227"></iframe> Title Description <p msthash="158" msthidden="1" msttexthash="151784919">This LED Dimmer Circuit uses a 555 Timer to control the PWM duty cycle of the current drive. Rather than apply proportional but continuous current to the LED for dimming, which can cause color shifts, modulating the duty cycle allows the LED to operate at its nominal current during the “ON” portion of the cycle. Because the frequency response of human vision is limited, using a PWM frequency of 250 Hz avoids the perception of flicker for the observer.</p> <p msthash="159" msthidden="1" msttexthash="89420448">The LED model has an internal monitor for the "perceived" light output (blue waveform), which is a low-pass filtered version of the instantaneous light output. The filter pole frequency is set to 15 Hz to represent the bandwidth of the human eye. The value of the dimmer setting (green waveform) is increased from 10% to 90% at time 100msec. The LED current pulses (red waveform) are shown before and after the duty-cycle transition.</p> <p msthash="160" msthidden="1" msttexthash="2417844">Part of this design is based on a dimmer schematic found on-line:</p> <p msthidden="1"><a msthash="161" msthidden="1" msttexthash="1874431" href="http://www.555-timer-circuits.com/led-dimmer.html">http://www.555-timer-circuits.com/led-dimmer.html</a></p> <p msthash="162" msthidden="1" msttexthash="61448530">That original circuit is actually incorrect, one of the diodes connected to pin 7 on the 555-Timer needs to be reversed. There was a comment from a reader who said he built the circuit as shown and it didn’t work. This is a good example of the value of simulating circuits before building hardware!</p> About text formats Tags 555 TimerLEDpotentiometer Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None -
Copy of LED Dimmer Circuit using 555 Timer - on Sun, 01/14/2024 - 13:52 Designer253181 × Member for 1 year 4 months 0 designs 1 groups Welcome to the community!! https://explore.partquest.com/node/630227 <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/630227"></iframe> Title Description <p msthash="158" msthidden="1" msttexthash="151784919">This LED Dimmer Circuit uses a 555 Timer to control the PWM duty cycle of the current drive. Rather than apply proportional but continuous current to the LED for dimming, which can cause color shifts, modulating the duty cycle allows the LED to operate at its nominal current during the “ON” portion of the cycle. Because the frequency response of human vision is limited, using a PWM frequency of 250 Hz avoids the perception of flicker for the observer.</p> <p msthash="159" msthidden="1" msttexthash="89420448">The LED model has an internal monitor for the "perceived" light output (blue waveform), which is a low-pass filtered version of the instantaneous light output. The filter pole frequency is set to 15 Hz to represent the bandwidth of the human eye. The value of the dimmer setting (green waveform) is increased from 10% to 90% at time 100msec. The LED current pulses (red waveform) are shown before and after the duty-cycle transition.</p> <p msthash="160" msthidden="1" msttexthash="2417844">Part of this design is based on a dimmer schematic found on-line:</p> <p msthidden="1"><a msthash="161" msthidden="1" msttexthash="1874431" href="http://www.555-timer-circuits.com/led-dimmer.html">http://www.555-timer-circuits.com/led-dimmer.html</a></p> <p msthash="162" msthidden="1" msttexthash="61448530">That original circuit is actually incorrect, one of the diodes connected to pin 7 on the 555-Timer needs to be reversed. There was a comment from a reader who said he built the circuit as shown and it didn’t work. This is a good example of the value of simulating circuits before building hardware!</p> About text formats Tags 555 TimerLEDpotentiometer Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None -
