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Staff Firmware Engineer - Charger

1X Technologies· Software Engineering
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San Carlos, CA$200k - $280kFull-timePosted 3mo ago

About the role

Staff Firmware Engineer responsible for charger firmware and embedded control across power conversion stages, CAN/BMS interfaces, and safety-critical charging functions for humanoid robot subsystems.

Responsibilities

  • Develop and maintain charger firmware controlling AC-DC power conversion stages, including power factor correction and isolated DC-DC conversion topologies
  • Implement charge profile management for multi-series lithium-ion packs: constant-current, constant-voltage, and taper phases with cell-chemistry-appropriate voltage and current limits
  • Architect the charger-to-BMS communication interface over CAN or similar embedded bus, coordinating charge current requests, pack voltage feedback, temperature limits, and fault signaling between the two subsystems
  • Responsible for the testing, validation, and verification of initial firmware releases to ensure functionality, reliability, and performance requirements are met
  • Implement power converter control loops in firmware: voltage regulation, current regulation, and soft-start sequencing with stability under varying line and load conditions
  • Develop fault detection and protection firmware: input overvoltage/undervoltage, output overcurrent, overtemperature, ground fault, and loss-of-communication with the BMS, each with defined safe-state transitions

Qualifications

  • 5+ years of embedded firmware development in C/C++ on real hardware, with direct experience managing interrupts, DMA, and timing-critical execution (7+ years for senior/staff-level positions)
  • Power conversion fundamentals working understanding of switched-mode power supply operation: common AC-DC topologies (flyback, LLC, phase-shifted full bridge), power factor correction stages, transformer isolation, and how firmware-controlled parameters affect converter behavior
  • Battery charging knowledge: understanding of lithium-ion charge protocols (CC-CV, multi-stage), the relationship between charge rate and cell degradation, and how temperature and cell age affect charge termination criteria
  • Embedded bus fluency hands-on CAN implementation for charger-to-BMS coordination, plus SPI, I²C, UART for communication with power controller ICs, monitoring devices, and auxiliary circuits
  • Hardware debug at the firmware boundary experience using oscilloscopes, current probes, and power analyzers to diagnose problems that span firmware control behavior, converter waveform quality, and thermal performance

Skills

Required:Deep embedded instinctsFirst-principles problem solvingSafety-aware by defaultCross-functional collaboration

Benefits

  • Comprehensive medical, dental, and vision coverage
  • Generous paid time off, company holidays, and parental leave
  • 401(k) plan with company match (100% on the first 3% of contributions, 50% on the next 2%)
  • Flexible Spending Accounts (FSA) and Health Savings Accounts (HSA) options
  • Commuter benefits (transit and parking)
  • Short-term and long-term disability, and life insurance
  • Employee Assistance Program (EAP) for mental health, financial, and personal support
  • Onsite snacks and catered lunches
Last updated Oct 18, 2026. Interested? Apply on the company site.
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About 1X Technologies

1X | Home Robots

We're an AI and robotics company based in Palo Alto, California. We create safe humanoid robots that do your chores and offer personalized assistance.

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