Staff Firmware Engineer - Charger

About the Team

The Firmware team owns the embedded software layer that powers every hardware subsystem of our humanoid robot from distributed communication bus architecture and power management to actuator and motor drive control. We sit at the intersection of hardware and software, and our work is directly on the critical path to every product milestone: without reliable firmware, the robot cannot move, charge, or operate safely. If you want to build the foundational software for a new category of physical AI, this is where that work happens.

Your Charter

Own the firmware layer across one or more of the robot’s core hardware subsystems—ensuring embedded software that is robust, safe, and maintainable across prototype and production platforms. As one of the first companies building general-purpose humanoid robots at scale, firmware quality is non-negotiable: it determines whether the robot operates safely in uncontrolled environments, whether hardware brings up on schedule, and whether the team can move fast as the system grows to 20+ distributed embedded nodes.

Key Outcomes

• 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

Key Competencies

• Deep embedded instincts writing firmware that is correct under real hardware conditions: interrupt timing, DMA conflicts, communication protocol edge cases, and hardware fault behavior
• First-principles problem solver diagnosing novel failures at the firmware-hardware boundary using lab tools and reasoning from fundamentals, not just vendor documentation or established patterns
• Safety-aware by default understanding what “fail safe” means in a physical system and treats protection logic, fault detection, and safe-state transitions as first-class firmware concerns
• Effective cross-functional partner translating firmware constraints and failure modes clearly to hardware architects, electrical engineers, and systems engineers; supports bring-up without waiting to be directed

Minimum Requirements

• 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 (switching frequency, duty cycle, phase shift) 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 additional embedded interfaces (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

Preferred Skills

• Domain depth in one or more areas relevant to humanoid robot subsystems: distributed real-time communication bus firmware, switched-mode power conversion and lithium-ion battery charge management, or motor drive and actuator control firmware
• Experience with safety-critical or fault-tolerant embedded systems; familiarity with safety integrity standards such as IEC 61508 or ISO 26262
• Familiarity with real-time operating systems (FreeRTOS, SafeRTOS, or similar)
• Background in robotics, autonomous systems, or complex electromechanical products

Compensation Range

$200,000 – $280,000 + Equity

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

Equal Opportunity Employer

1X is an Equal Opportunity Employer. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex, gender, gender identity or expression, sexual orientation, national origin, ancestry, citizenship, age, marital status, medical condition, genetic information, disability, military or veteran status, justice system impact, or any other characteristic protected under applicable federal, state, or local law.