DEC1622 Team Leader : Wei Shen Theh Communication Leader : Jiayu - - PowerPoint PPT Presentation
Fast, Compact, High Strength Magnetic Field Generator DEC1622 Team Leader : Wei Shen Theh Communication Leader : Jiayu Hong Key Concept Holder : Aqila Sarah Zulkifli Webmaster : Wing Yi Lwe Advisor: Dr. Mani Mina Co-advisors: Neelam Prabhu
Team Leader : Wei Shen Theh Communication Leader : Jiayu Hong Key Concept Holder : Aqila Sarah Zulkifli Webmaster : Wing Yi Lwe Advisor: Dr. Mani Mina Co-advisors: Neelam Prabhu Gaunkar, : Jayaprakash Selvaraj Client : Iowa State University’s High Speed System Engineering Lab
dec1622@iastate.edu
dec1622@iastate.edu
1. Objective 2. Applications 3. Project Flow 4. Circuit Block Diagram 5. Schematic Diagram 6. Design Process a. FET Options b. Coil Size
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Objective
Requirements
Our focus
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Source: New developments in magneto-optic interferometric switching by John Pritchard
Figure: Sagnac Interferometer
MO Material
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Source: New developments in magneto-optic interferometric switching by John Pritchard
dec1622@iastate.edu
dec1622@iastate.edu
When MOSFET is turned off, DC source charges capacitors Pulse is fed to control the switching
Capacitor releases stored energy to inductor coil Output current is measured through current sense resistor When MOSFET is turned
inductive coil is dissipated as heat through resistor Diode ensure current does not pass through discharge resistor when switch is on 1 3 2 7 6 Inductor coil generates magnetic field 5 4
dec1622@iastate.edu
dec1622@iastate.edu
Switch options: MOSFET Darlington Considerations: MOSFET - Faster switch Darlington - BJT based
BJT - NPN Darlington structure NMOS
Source: ibiblio.org Source: thinkelectronics Source: keysight
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L=200pH Improved rise time makes MOSFET our favored switch!
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Input Capacitance: PSMN4R0-30YLD (1272 pF) CSD17322Q5A (580 pF) IRL3714S (670 pF) PSMN1R2-30YLD (4616 pF) Time Constant:
D S Cgd Cgs Cds
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102nH: length:0.6cm,radius:0.25cm, turns:5 78nH: length:0.5cm,radius:0.20cm, turns:5
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○ 10% - 90% ○ 20% - 80% Two Inductors: 102nH & 78nH Two different set of input: 1us & 2us
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Source: http://may1530.ece.iastate.edu/
500 Gauss 1 us 2” x 1.5”
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Importing footprints and SPICE files Tiny components Protomat has limiting functions:
Single layer No plated through hole
No experience with:
Eagle layout Protomat
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Footprint: 1.5” x 1.875”
huge input capacitance (4616 pF)
○ Positive DC input is not connected to the rest of the circuit
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Footprint: 2.2” x 1.95”
Inductance 102 nH 78.5 nH Rise time (10% - 90%) 744 ns 664 ns Rise time (20% - 80%) 612 ns 504 ns Mean voltage 0.64 V 0.68 V Max voltage 0.8 V 0.84 V Magnetic flux density 167.5 G 157.93 G
First working board! Same NXP MOSFET Low magnetic flux density (167 Gauss) Slower rise time (>100ns) Relatively large footprint (within 2’’x 2’’)
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TI CSD17322Q5A with low input capacitance (580 pF) Shorter rise time (9x faster) Board performing as expected
Inductance 102 nH 78.5 nH Rise time (10% - 90%) 83.200 ns 129.967 ns Rise time (20% - 80%) 58.467 ns 94.313 ns Mean voltage 1.640 V 2.027 V Max voltage 1.640 V 1.947 V Magnetic flux density 343.481 G 407.709 G
Footprint: 1.8” x 1.4”
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Without zener protection circuit Decreased magnetic flux density (20G) Rise time further decreases (26 ns) Ground terminals positioned closer Spiking and oscillation improved Board size decrease
Inductance 102 nH 78.5 nH Rise time (10% - 90%) 56.990 ns 86.297 ns Rise time (20% - 80%) 31.530 ns 54.507 ns Mean voltage 1.527 V 1.527 V Max voltage 1.540 V 1.567 V Magnetic flux density 322.537 G 328.122 G
Footprint: 1.5” x 1.1”
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Inductance 102 nH 78.5 nH Rise time (10% - 90%) 60.690 ns 69.850 ns Rise time (20% - 80%) 39.480 ns 48.177 ns Mean voltage 1.24 V 1.23 V Max voltage 1.36 V 1.23 V Magnetic flux density 284.838 G 258.309 G
Footprint: 1.5” x 1.25”
Without zener protection circuit IRF IRL3714S (670 pF input capacitance) Low magnetic flux density and short rise time Ground terminals routed together
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Based on layout design 3 NXP PSMN4R0-30YLD (1272 pF input capacitance) Industry PCB and reflow oven soldering Inductor coil soldered onto board
Inductance 102 nH Rise time (10% - 90%) 111.45 ns Rise time (20% - 80%) 75.635 ns Mean voltage 2.08 V Max voltage 2.08 V Magnetic flux density 435.63 G
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Final Board Project Specification Previous Work Rise time 111.45 ns 100 ns ~500 ns Magnetic flux density 435.63 G 500 G 500 G Footprint 1.8” x 1.4” 2” x 2” 2” x 1.5” Cost per board(approx) $28
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dec1622@iastate.edu
Layout 2 Layout 3 Layout 4 Layout 5 102nH 78nH