Electronics design
End-to-end electronics design services from concept to production.
Specialised engineering
Power Electronics Design: BMS, DC-DC, EV Charging and Motor Control
Power electronics for battery-powered and high-voltage products: battery management systems, isolated and non-isolated DC-DC converters with GaN or SiC switches, 48 V and 800 V architectures, EV charging electronics and motor drives. We design the power stage, magnetics, protection and control firmware together, and prepare the product for safety and EMC testing.
Quick answer
- What we build
- Battery management systems, GaN and SiC DC-DC converters, 48 V and 800 V power stages, EV charging electronics and motor drives, covering the hardware, magnetics and control firmware.
- Who it is for
- EV, energy-storage, robotics and industrial companies, and power-module makers, that need a power stage, BMS or motor controller designed, or an existing design fixed.
- Typical timeline
- Set in the proposal after a requirements review
- Typical cost
- Quoted per project as a fixed-scope proposal. For typical ranges, see our hardware development cost benchmarks.
- Designed to
- IEC 61851-1 for EV charging, ISO 6469 and ISO 26262 for vehicles, IEC 62619 and AIS-156 for batteries, IEC 62368-1 for power supplies and IEC 61000 for EMC, as the product requires.
What we deliver
What power electronics do we design?
Battery management systems
BMS hardware and firmware: cell monitoring and balancing, state-of-charge and state-of-health estimation, hardware protection and CAN communication for Li-ion NMC and LFP packs.
DC-DC converters
Isolated and non-isolated converters, from point-of-load stages to 800 V to 48 V intermediate bus converters, using GaN, SiC or silicon switches.
48 V and 800 V architectures
Insulation coordination, pre-charge and discharge circuits, isolated sensing and insulation monitoring for high-voltage battery and bus systems.
EV charging electronics
On-board chargers with power-factor correction, AC charging-station control, DC and bidirectional power stages, and ISO 15118 vehicle-to-charger communication.
Motor drives
BLDC and PMSM inverters with field-oriented control firmware, from micro-motors in robotic hands to vehicle motor controllers.
Energy storage and solar
Battery management and control electronics for energy-storage systems, and MPPT charge controllers for solar and energy-harvesting products.
Battery management
What does a BMS design project include?
A BMS protects the pack and reports its state. We design the hardware and firmware together, because protection, balancing and state estimation each depend on both.
- Cell monitoring and balancing
- Cell-voltage and temperature measurement with a dedicated monitoring IC (for example TI BQ769x2, Analog Devices ADBMS/LTC681x or NXP MC33771, chosen for the cell count and chemistry), passive or active balancing, and pack current sensing by shunt or Hall sensor.
- Protection that does not depend on the microcontroller
- Hardware overcurrent, short-circuit, over- and undervoltage and overtemperature cut-offs that act independently of the MCU, with MOSFET or contactor disconnect, pre-charge and, for high-voltage packs, isolation monitoring.
- State estimation
- State of charge from coulomb counting corrected by voltage-based estimation, and state-of-health tracking over the life of the pack, for Li-ion NMC and LFP chemistries.
- Communication and integration
- CAN or CAN FD to the vehicle or system controller, logging and diagnostics, firmware updates and, for traction packs, the functional-safety analysis the vehicle programme requires.
DC-DC conversion
How do you design a DC-DC converter with GaN or SiC?
Converter work starts from the electrical and thermal requirements: input range, output, power, isolation, efficiency and temperature. These are recorded as design targets and compared with measured results on the prototype.
- Topology
- Non-isolated buck, boost and multiphase stages; isolated LLC resonant, phase-shifted full-bridge and dual-active-bridge stages for bidirectional power flow. The choice follows the voltage ratio, power level, isolation requirement and efficiency target.
- GaN, SiC or silicon
- GaN transistors suit high switching frequencies and power density at lower voltages, such as 48 V stages. SiC MOSFETs suit high-voltage stages, such as an 800 V input. Silicon stays the lower-cost choice where frequency and efficiency targets allow. Gate drive, dead time and layout follow the device chosen.
- Magnetics, layout and thermal design
- Transformer and inductor design, low power-loop inductance in the PCB layout, creepage and clearance for the working voltage, and a thermal path from the switches and magnetics to the heatsink or baseplate.
- Control and protection
- Analog or digital control (for example on a TI C2000 or STM32G4 microcontroller), loop compensation, soft start, current limiting and input and output protection, with telemetry to the host system where needed.
48 V and 800 V
What changes between 48 V and 800 V designs?
The voltage class sets the safety architecture before any component is chosen.
- 48 V systems
- A 48 V bus sits below the 60 V DC limit commonly used for safety extra-low voltage, which simplifies insulation, but currents are high: busbar and connector ratings, current sensing and thermal design dominate the design.
- 400 V and 800 V systems
- Reinforced insulation, creepage and clearance to IEC 60664-1, isolated gate drivers and isolated sensing across the barrier, pre-charge, discharge and interlock circuits, and insulation-resistance monitoring.
- 800 V to 48 V conversion
- Isolated intermediate bus converters that step an 800 V DC bus down to 48 V or 54 V for electronic loads, with SiC switches on the high-voltage side and GaN or silicon on the low-voltage side where the design calls for it.
- Safety and EMC evidence
- Design documentation and test plans for dielectric-strength (hi-pot), insulation-resistance, safety and EMC testing at an accredited laboratory.
EV charging
What EV charging electronics do you design?
- On-board chargers
- AC-DC on-board chargers with power-factor correction and an isolated DC-DC stage, sized to the vehicle's battery voltage and charging power.
- AC charging stations
- Charging-station control electronics: control-pilot signalling to SAE J1772 and IEC 61851-1, contactor control, thermal management and load balancing across charge points.
- DC and bidirectional charging
- Power-conversion and control electronics for DC charging, and bidirectional stages for vehicle-to-grid (V2G) operation, with ISO 15118 communication for Plug & Charge.
- Connected chargers
- OCPP connection to the charge-point management system, remote diagnostics and OTA firmware updates, built with our firmware and cloud teams.
Motor control
What does a motor-control project include?
Motor control combines a power stage, current and position sensing, and real-time firmware.
- Power stage
- Three-phase inverter or H-bridge stages with gate drivers, shunt or Hall current sensing and fault protection, sized from robot micro-motors to vehicle motor controllers.
- Control firmware
- Field-oriented control (FOC) for BLDC and PMSM motors, six-step commutation where it is enough, and speed and position loops using Hall sensors, incremental encoders or sensorless estimation, on microcontrollers with motor-control timers such as the STM32G4.
- Robotic actuators
- Compact multi-axis drivers for coreless and brushless micro-motors with high-resolution encoders, for dexterous hands, grippers and prosthetics.
- Fault handling and EMC
- Overcurrent, stall and overtemperature handling, and layout and filtering to control conducted and radiated emissions from the switching stage.
How we work
How we work
Requirements and safety targets
Agree the electrical, thermal, safety and regulatory requirements; efficiency, power-density and temperature figures are recorded as design targets.
Deliverable: Requirements and design-target sheet
Architecture and simulation
Select the topology, switching devices and control approach; estimate losses and temperatures; simulate the power stage and control loop.
Deliverable: Architecture, loss budget and simulation results
Schematic, magnetics and layout
Schematic, magnetics design and a PCB layout with low loop inductance, creepage and clearance for the working voltage, and a defined thermal path.
Deliverable: Schematic, layout, magnetics specifications and BOM
Prototype and characterisation
Bring-up at reduced voltage first, then efficiency, thermal, transient and protection tests, reported as measured values against the design targets.
Deliverable: Characterisation report with measured results
Compliance preparation and handoff
EMC pre-compliance, safety and EMC test plans for the accredited laboratory, and the manufacturing release package.
Deliverable: Test plans, compliance documentation and release package
Scope and cost
Scope and cost
Start with a non-confidential summary of your product and the milestone you need to reach next.
Plan a power electronics project
Background reading on the standards, devices and industries this work usually involves.
- ISO 26262 functional safety: what a BMS or motor controller in a vehicle has to show
- GaN bidirectional switches: PCB layout and topology notes
- Automotive and EV electronics: BMS, on-board chargers and motor controllers for vehicles
- Energy and utilities: energy storage, solar and grid-edge electronics
- Hardware development cost benchmarks
FAQ
Frequently asked questions
Yes. The cell monitoring, protection and balancing hardware and the firmware for state-of-charge and state-of-health estimation, protection logic and CAN communication are designed together, because each depends on the other. We can also take over and extend an existing BMS design.
It depends mainly on voltage, switching frequency and cost. GaN transistors are usually preferred for high-frequency, high-density stages at lower voltages, such as 48 V converters. SiC MOSFETs are usually preferred for high-voltage stages, such as 800 V inputs, and for high-temperature operation. Silicon remains the lower-cost option where frequency and efficiency targets allow. We compare the options on losses, thermal design, gate-drive complexity, availability and cost before committing.
Yes. 800 V designs are built around reinforced insulation, creepage and clearance for the working voltage, isolated gate drive and sensing, pre-charge and discharge circuits and insulation monitoring. Formal safety and EMC testing is carried out at accredited laboratories; we prepare the test plans and documentation.
Commonly IEC 61851-1 for EV charging systems and ISO 15118 for vehicle-to-charger communication; ISO 6469 and ISO 26262 for on-vehicle electrical safety and functional safety; IEC 62619 for industrial lithium batteries and, in India, AIS-156 for the traction batteries of L-category electric vehicles; plus the EMC standards of each target market. The applicable set depends on the product and market and is agreed at the start of the project.
Yes. We write field-oriented control (FOC) for BLDC and PMSM motors, and six-step commutation where that is enough, with current, speed and position loops using Hall sensors, encoders or sensorless estimation, together with the inverter or driver hardware.
Working with Rapid Circuitry
How much does a project cost, and how is pricing structured?
Each project is quoted as a fixed-scope proposal: a statement of work with milestones, deliverables and pricing, sent within 3–5 business days of the discovery call. The price depends on the requirements, how mature the design is, technical complexity, the number of prototype iterations and the validation scope. Longer engagements can also run as a retainer or a hybrid of both. For budgeting before you contact us, our hardware development cost benchmarks and the PCB design, firmware and IoT cost guides give indicative ranges with their assumptions stated. They are planning ranges, not quotes.
How long does a project take?
It depends on the scope and on what already exists when we start. As planning ranges from our cost benchmarks: a single PCB design takes 2–6 weeks, embedded firmware 4–16 weeks, an end-to-end IoT product 3–9 months and a regulated medical device 9–18 months. The proposal sets out a dated milestone plan, and you receive weekly progress updates during the project.
Who owns the intellectual property?
You do. Our contracts assign the project work product — schematics, PCB design files, firmware source code and documentation — to you as work for hire, and we hand over the source files, not only fabrication outputs or compiled binaries. The exact terms are set out in the signed agreement for each engagement.
Do you sign NDAs?
Yes. We sign a mutual NDA before any technical discussion of your project. Send your standard NDA or use ours; we return it signed within one business day.
Can you work with clients in the US, Europe and Japan?
Yes. We are based in Hyderabad, India, and work with product teams in India, the United States, the United Kingdom, Germany and other markets. Our business hours are 09:00–18:00 India Standard Time (UTC+5:30), and we schedule design reviews across time zones, typically from US Pacific to Central European time. Japan is 3.5 hours ahead of India, so a Japanese working day overlaps our morning and early afternoon. Prototypes and documentation ship by international courier such as DHL or FedEx. Our hardware outsourcing guide covers what to agree before an international project starts.
Do you hand off to manufacturing, and which contract manufacturers do you work with?
Yes. We prepare the manufacturing release package — fabrication and assembly drawings, the BOM with approved manufacturers, programming files and test specifications — and hand it over to the contract manufacturer (EMS) you choose. If you have not chosen one, we help you evaluate candidates through technical capability assessments and a pilot build. See manufacturing support.
Are you ISO 9001 or ISO 13485 certified?
No. Rapid Circuitry does not hold ISO 9001, ISO 13485 or other certificates. Our processes are aligned with ISO 9001:2015, and we design products to the requirements of the standards that apply to them — for example IEC 60601-1, IEC 62304 and ISO 13485 for medical devices, IEC 61000 for EMC and IPC-A-610 for assembly. We prepare the product and its documentation for certification testing at accredited laboratories; the certificate or approval is issued for your product by the laboratory, notified body or regulator.
What do you need from me to start?
A short, non-confidential description of the product and what it must do (sensors, connectivity, on-device processing), the target production volume and unit cost, the markets and regulations it must meet (for example FDA, CE or FCC), your timeline, and what already exists: a concept, a proof of concept, schematics, PCB files or firmware. After the NDA, the next step is a 30-minute discovery call with the engineers who would work on the project, followed by the fixed-scope proposal. Send a project brief to begin.
Related
Related services
Firmware development
Custom firmware and embedded software development for your hardware solutions.
Connected vehicles
Automotive IoT and connected vehicle solutions.