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Supplemental Monitoring Hat

Supplemental Monitoring Hat

Status

 

Owner

@Abigail Parsons

Approver

@Ravi Shah

Due date

 

GitHub

https://github.com/lhr-solar/PS-LVCarrierPCB/tree/main

BOM

 

Due Dates:

  • Requirements/Considerations -

  • Component Selection -

  • Initial Schematic -

  • Initial Layout -

  • Rev. A Ordered -

  • Firmware/Testing -

Description/Purpose

  • PCB that measures the voltage and current of the supplemental battery with an output regulator

Requirements

Electrical Regulation & Safety

  • Stable regulated output → Prevents downstream circuits from brownout due to battery droop.

  • Overcurrent protection → Regulator should protect against overcurrent nominally, but in case of regulator fail / short, include a fuse before regulator for extra protection (10-15A)

  • Undervoltage cutoff → Protects NiMH cells from deep discharge.

  • Reverse polarity protection → Guards against incorrect wiring / use.

Measurement & Monitoring

  • Pack voltage monitoring → Monitoring both before and after regulator. Before for UV cutoff and protection, after for downstream circuit Power Good validation / regulator stability (logic & this with PGood on Vicor itself).

  • Input and output current sensing → Enables efficiency calc + fault detection. Before for fault detection (if we see a good voltage on Vicor input end but its not drawing any current → vicor is prob cooked), after for total LV power consumption reading + overcurrent protection.

  • Pack internal temperature → Prevents overheating of cells under load.

  • SoC?

Indicators

  • 7-segment, 3-digit → Pack voltage (before regulator), format XX.X V.

  • Green, solid → Power OK / Reg output within tolerance (normal).

  • Yellow, solid → Battery Voltage Low

  • Red, solid → Fault (temp, over current, egregious low batt voltage).

Application Note

Context

Location of the board: On top of the LV Carrier PCB

Connection List

#

Name

Type

Part Number

#

Name

Type

Part Number

J6

Input/Output

UTSVT_Connectors

524652470

Main

Schematics

Circuit Components

Dual Op Amplifiers: TLV9002QDRQ1

TLV9002QDRQ1 Data Sheet

Seven Segment LED: 

INND-SS30 Series 0.3” SMD Single Digit Display

8-bit Shift Register: SN74HCS595DYYR

SN74HCS595 8-Bit Shift Register With Schmitt-Trigger Inputs and 3-State Output Registers datasheet (Rev. B)

 

Layout

Github link: https://github.com/lhr-solar/PS-LVCarrierPCB/tree/main

PCB:

3D Model

RevB Testing

Hardware Test

  • Make sure all components are soldered correctly with no shorts. - ✅

  • Verify the status LED turns on with power - ✅

  • Verify that the board powers on -✅

  • Confirm that the pre-regulator voltage input handles 18-32 V range.

  • Make sure that all input voltage is within the Op-Amp operating range.

  • Verify no excessive voltage drop through connector/anywhere on board.

  • Verify unity-gain and filters work with a multimeter.

  • Use Supp Mon Test Board to ensure everything has the correct expected voltage input/output.

  • Confirm the shift registers/seven segments are working and turn on - ✅

  • Check the test points when the board is powered on. -

Driver Test - not done

  • Seven Segment using shift register driver - ✅

  • Does it consistently update the voltage? - ✅

  • Does each display turn on with the correct value? - ✅

  • All the pins are initialized correctly - ✅

Firmware

Drivers

  • Shift Register/Seven Segment Driver.

High-Level (Block Diagram)