What it does

Charges the DC link through your precharge resistor, continuously measures ΔV across that resistor, and—when ΔV falls below a set threshold—closes a precharge contactor to bypass the resistor.

Pure analog decision chain: divider → instrumentation amplifier → Schmitt comparators → logic gates (no firmware, no boot time, no microcontroller).

Isolation & protection

• Full galvanic isolation between HV sense and GLV/contactor domains (isolated GLV supply + opto isolation).

• On-board GLV input fuse and built-in reverse-polarity protection.

• Contactor driver up to 2 A with integrated flyback for coil suppression.

Indicators & STATUS output

• LED: HV Present (pack detected on sense lines).

• LED: Precharge Complete (contactor commanded).

• STATUS pin: Active-HIGH output (driven HIGH via a PFET when precharge is complete; bleeds down toward GND when not complete). Output level ≈ your GLV rail. If your ECU expects 3.3/5 V, use a divider or isolator. NOTE: This pin is very important. If at any point this pin is not active, DO NOT allow an inverter, motor controller, or other HV load to pull any significant amount of current.

Recommended HV operating range:

• Nominal packs up to ~400 VDC (limited by rating on input screw terminal block, front end works up to 600V)
• Usable low end: ~24–36 V; best margin ≥ 40 V for crisp comparator trip.

Hook-up guide

Terminals

GLV+ / GLV– (9–36 V): Board power (on-board fused & reverse-protected).

COIL+ / COIL–: Main contactor coil (≤ 2 A).

PACK+ SENSE / LOAD+ SENSE: High-impedance sense leads—one upstream of the precharge resistor (battery side), one downstream (bus side).

STATUS: Logic output, active-HIGH on precharge-complete (≈ GLV level).

System wiring

Place your precharge resistor between PACK+ and LOAD+.

Wire the main contactor in parallel with that resistor.

Run thin, twisted sense leads to PACK+ SENSE and LOAD+ SENSE (keep away from noisy conductors).

Connect GLV power, the contactor coil, and (optionally) route STATUS to your ECU/BMS/PLC input.

Use ferrules on stranded conductors. Designed to be mounted in an 80×72 mm DIN-rail carrier.

Specs (summary)

• GLV input: 9–36 V (12/24 V nominal), on-board fused & reverse-protected

• Contactor drive: ≤ 2 A coil, integrated flyback

• Isolation: HV sense ↔ GLV domains fully isolated

• Indicators: HV-present LED, Precharge-complete LED

• STATUS output: Active-HIGH, ≈ GLV level (PFET-driven)

• Form factor: 80×72 mm PCB; fits standard DIN-rail carrier

Use cases: EV/AGV, robotics, energy storage, lab power carts; commonly alignable with FSAE-EV precharge architectures (teams must verify current rules)

Comes fully assembled. You provide the DIN rail case, or design your own. All components on the PCB and the PCB itself are RoHS compliant. This is for evaluation/prototype use only. Use will require encasement and will be at your own risk after reviewing the schematic. Also, note that the item displayed in the pictures is v1.1 of the board, and we will be shipping v1.2, so it will look slightly different (with no functional differences).

DATASHEET IS LTSPICE SIM FILES