v1.0 HW issues

[gkasprow]

• [ ] N1V8 rail value depends on 5V load. Without the load, it's +0.5V. With 1A load it's -2V. I had to lower R95 to 100R. Let's replace it with LMC7660

[gkasprow]

• [ ] use tht connectors only for modules to avoid alignment issues

[gkasprow]

• [ ] fix the module HV dc/dc footprint

[gkasprow]

• [ ] unify RC footprints

[gkasprow]

• [ ] swap R24 with R25 on channel PCB

[gkasprow]

• [ ] add 1u cap and change R to 10k

[gkasprow]

add debug LEDs:

• [ ] - supply on external sensor
• [ ] - HV divider resistor selected

[gkasprow]

• [ ] GPIO12 is strapping pin and should be avoided

[gkasprow]

• [ ] add rpi connector and mechanical fixing

[gkasprow]

• [ ] add 1u cap and change 1k-> 10k at the main board , too

[gkasprow]

• [ ] add HV discharge circuit?

[gkasprow]

• [ ] fix heavy dc/dc converter both on the mainboard and on the channel board

[gkasprow]

• [ ] consider using better 5V reference for DAC instead of ADP7102ARDZ-5.0-R7

[gkasprow]

• [ ] Add HV present LED based on divider current measurement

[gkasprow]

• [ ] add cutout under wifi antenna on the mainboard

[gkasprow]

• [ ] channel numbering from 0

[gkasprow]

• [ ] change module HV resistor switch - instead of T15 use another AQV224NS

[gkasprow]

• [ ] increase the number of series resistor for drift (HV7). We may expect up to 2kV there

[gkasprow]

• [ ] change divider resistors to 2010 - we may get 700V there

[gkasprow]

• [ ] Make 4 bit HV resistor setting

[gkasprow]

• [ ] add interlock input

[gkasprow]

• [ ] Add DIP-switches or jumpers and standard resistors on mainboard

[gkasprow]

• [ ] missing R from divout to GND

[gkasprow]

• [ ] add HVQC 2x BJT+divider - we need even 2.5kV
• [ ] add main pcb fixing holes + spacers

[gkasprow]

• [ ] R71=200k

[gkasprow]

• [ ] debug LED on each channel

[gkasprow]

• [ ] consider using opamp with lower Vos or use higher gain, for the moment we have 0.256V ADC range

[gkasprow]

• [ ] add HV locking feature - for the moment HV DC/DC gives max voltage during turning on - BSS138+bat54c+10u+240k

[gkasprow]

• [ ] add measurement of the additional divider / emitter follower voltage on the main board instead of 12V U meas

[gkasprow]

• [ ] make the adjustment range much smaller. now is 450-590V for channel 0

[gkasprow]

• [ ] Design 3d printed cover for each HV module that also holds the DC/DC converter

[gkasprow]

• [ ] add opamp for precise HV setting - the ADJ input of the converter is non-linear. DC/DC input is reversed, 0 means max, 5V means min voltage.

[gkasprow]

• [ ] add 100k series resistors with HVSET0, HVSET1 to prevent turning on T1 when one of MSOFETs breaks

[gkasprow]

• [ ] add dedicated measurement input on HVQ_C to enable measurement of HV on the channel 6 (+ add external measurement resistor)

[gkasprow]

• [ ] remove SMAJ5 TVS - now it affects module output current measurement; replace by 2 fast low Iq diodes: BAV199-AQ

• [ ] modify global current measurement - make it linear instead of logarithmic; measure difference between 2 dividers

[gkasprow]

• [ ] now the 100nF capacitor on the module doesn't make much sense because it's not in parallel with the full divider

[gkasprow]

• [ ] add TVS for T1

[gkasprow]

• [ ] add PNP part of the divider

[gkasprow]

• [ ] add a fast comparator to detect discharges

[gkasprow]

• [ ] add HV LC filter

[gkasprow]

• [ ] add socket for main HV DC/DC (PCB insert)

[gkasprow]

• [ ] use differential divider current measurement

[gkasprow]

• [ ] replace S1M with sth much faster and lower Ir ACURN105-HF; CD214A-RS1M; RS1MWF-7

[gkasprow]

• [ ] add current limit measurement circuit (6V source should be fine)

[gkasprow]

• [ ] add opamp to boost DAC output to 5V or more; now with 4.096V, we can get max 40uA output current with poor accuracy

[gkasprow]

• [ ] change HV net names to match mainboard - indexes 0->3; 1->2; 2->1; 3->0

[gkasprow]

• [ ] use lower voltage TVS on HV_LIM net - we have 800V MOSFETs now (STN1NK80Z)

[gkasprow]

• [ ] Add USB-A connector to power RPI
• [ ] Add fixing holes and standoffs above the HV DC/DC to fix RPI
• [ ] Add USBA to micro USB cable to the BOM
• [ ] Add Panel Mount Ethernet Extension Cable to the BOM or CP30220SX Keystone mount
• [ ] Add Power and status LEDs to the front panel (connection to HA)

[gkasprow]

• [ ] add 15mm plastic standoffs to the BOM
• [ ] add M3 6-8mm countersunk screws to the BOM
• [ ] add M3 8 mm Nylon screws to the BOM

[gkasprow]

• [ ] add GND terminal!!!

[gkasprow]

• [ ] move CH2 away from the enclosure support - the HV may destroy antenna