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Motor controller capacitors are currently charged with a constant voltage source and series resistor. This is always 50% efficient. For a challenger vehicle, it might be better to have a switching circuit (buck topology) to charge with constant current (which would also be faster).
Keep to 12V by removing DC DC inversion
Add hall effect sensor
Make simpler by removing irrelevant portions (e.g. fan control and thermistor may have been exclusive to MOV since shorts less of an issue?)
Research Summary
Switching Circuit[Not Choosing This. Prefer Hall Effect Current Sensor]Simplify Charge Pump and Depletion Mode FET (U4)Original parts
Charge pump switch regulator
Depletion mode FET
Remove DC-DC[Using different change]Remove all isolated 12V connectionReplace with VBAT
Replace HV FET with solid-state relays[May not implement. No big advantages for changes]Q1 and Q2 system to be entirely replaced with solid-state relaysEnd changesOne end from HV_INOther end to pre-chargeiso_latch_out might be removed?
Reverse it?
https://electronics.stackexchange.com/questions/261711/how-can-i-replace-a-relay-with-a-mosfet-transistorLinksPart SearchNew Change
Find closed switch to replace the two components
Part requirement
Normally closed relay
Form B (Form C can work)
https://forum.digikey.com/t/understanding-form-a-form-b-form-c-contact-configuration/811
Support
151.5V + safety factor (x1.5) [227.27V]
0.5A
Ratings at 60C
Controllable
Can close on-demand or
Closes when car close
Part Search
Remove entire middle section with Hall Effect Current SensorMust connect to IN+ and IN-Unsure if AND gate and MOSFETs need to be changed
LinksImplementation routes
For lower current parts
Add a series resistor to discharge path for lower current
Drawback
Slower to discharge (0.25s)
For lower voltage parts
Use relay in parallel
Less preferrable
Drawback
Expensive
May not share load equally (reduce one relay lifespan quicker)
Types of relay
Solid-state relay
AQY414SX512420AQZ404
400V
100mAand 0.5A (0.3A at 60C)
Datasheet below
350V120mAPreferring This One
ProductDetail/Panasonic-Industrial-Devices/AQZ404?qs=Wn4D5qJAqBJmKpb9gy8Awg%3D%3D (mouser link)
Need lower current part implementation
Form B (Normally closed)
https://www.digikey.ca/en/products/detail/panasonic-electric-works/
200V250mA
Add Hall Effect Current Sensor [Too complex to do in small time frame]
AQZ104
400V and 0.6A (~0.4A at 60C)
https://www.mouser.ca/ProductDetail/Panasonic-Industrial-Devices/AQZ104?qs=wKtUvITRiakdB78b%2F5Uijg%3D%3D (Need to wait till August for parts to ship)
Form A (Normally opened)
digikey.ca/en/products/detail/panasonic-electric-works/AQZ206G2/9597209
AQZ206G2
600V and 1A (~0.6A at 60C)
Datasheet below
Part searchCheck ratings (Current, voltage, sensitivity)CurrentVoltage120V?
Sensitivity[Check]0.806mV/A?3.3/2^12 (12bit ADC)
Industrial-Devices/AQZ206G2?qs=w%2Fv1CP2dgqpfmR1EUJ61AQ%3D%3D (Need to wait till September for parts to ship)
Form A (Normally opened)
Implementation plans
Existing parts
Remove
Charge pump and corresponding capacitors (C11, C12, C13, U4)
Series Resistor (R19)
Depends on parts
Pull-down resistor (R21)
Zener diode (D8)
Keep
LED and resistor (LED5 + R43)
Schematic
Q1 and Q2, replace with single relay
- stcomcontent/ccc/resource/technical/document/datasheet/cd/46/43/83/22/d3/40/c8/DM00090510.pdf/files/DM00090510.pdf/jcr:content/translations/en.DM00090510.pdf
ProductDetail/Panasonic-Industrial-Devices/AQZ104?qs=wKtUvITRiakdB78b%2F5Uijg%3D%3D
Cheaper ($12-16)
In stock
Current rating may not be enough at 60C
More Expensive ($30)
Have to wait
Enough current rating
Note: May not implement if not enough space
- stcomcontent/ccc/resource/technical/document/datasheet/cd/46/43/83/22/d3/40/c8/DM00090510.pdf/files/DM00090510.pdf/jcr:content/translations/en.DM00090510.pdf
Q3, use relay (AQZ404) with series resistor
Needs to be done
If approved, should buy early
Pre-charge timing
Using 270 uF Cap MC
300 ohm
500 ohm
Out of stock IC
Smaller changesIC Load Switch
OOS
NCP45521IMNTWG-H
Part listAlternative
NCP45770IMN24TWG
allegro-microsystems/ACS756SCB-050B-PFF-T/540076050ANo Stock :/onsemi/ncp45770imn24twg/12180092
CAN Controller
OOS
MCP2515T-I/ST
lemusa-incHO8NP-0000/43319748ANo Sensitivity
100ANo SensitivityMicrochip-Technology/MCP2515T-I-ST?qs=uMUszenkLLIwkGYxhCCgRQ%3D%3D
Alternative
MCP2515-E/P
digikeyenproducts/detail/tamura/L01Z200S05/529408200ANo SensitivityMicrochip-Technology/MCP2515-I-P?qs=hklUZQQMghMXVOd4j8inGA%3D%3DNote: Through-hole
CAN Reciever
OOS
Alternative
MCP2551T-I/SN
texasinstruments/TMCS1100A4QDR/12696002A?400 mV/A
Simplify Isolated DCDC
U4
U5
U9
Smaller changes (Check with)
Removing:
Fan control
Remove fan connector
Remove entire fan control sheet
Thermistor
Remove thermistor connector
Remove entire thermistor sheet
Add jumpers near AND gate to skip it
Part List
AQZ404 (Solid State Relay)
Replaces Q3
Needs to be with series resistor
IC Load Switch
CAN Controller
MCP2515T-I/SO
Present in the bay but OOS
CAN Reciever
Optoisolator
HCPL-0211-500E
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