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Medical-Grade 1kW 4kV Constant-Current AC-DC Power Supply with CAN Bus Control

A production medical-grade AC-DC constant-current 4 kV, 1 kW power supply with CAN bus control.

Advanced Project — This is advanced because it combines offline high-power conversion, 4 kV isolation and safety spacing, medical-grade compliance concerns, and CAN-controlled firmware with robust fault handling.
Assumptions:
  • The 4 kV output is isolated from mains and the CAN interface is on the low-voltage control side.
  • The user wants a custom PCB-based design, not an off-the-shelf enclosed supply.
  • Medical-grade implies reinforced isolation, low leakage current, and compliance-oriented design practices, but final certification is outside the scope of part selection.
  • The constant-current regulation is for the high-voltage output stage, with the MCU supervising setpoint, telemetry, and fault handling over CAN.

Bill of Materials

Microcontroller
Top Pick STM32G474RET6 STMicroelectronics From our database
STM32G474RET6 is the best overall pick here because it gives you a modern control-oriented Cortex-M4F, strong analog/timer peripherals, and a very practical firmware platform for supervising a 1 kW power stage while handling CAN-based commands and telemetry.
Digikey $9.05 (1,535 in stock)
ATSAME54N20A-AZVAO Microchip Technology From our database
Strong fit for production control: Cortex-M4 MCU with ample Flash/RAM, multiple serial interfaces, and enough headroom for CAN protocol handling, telemetry, fault logging, and control-loop supervision. Good choice when you need deterministic firmware, multiple ADC/PWM channels, and robust industrial control architecture.
NXP S32K144 NXP Semiconductors
Automotive/industrial-grade MCU with CAN support and a control-oriented feature set, making it a solid fit for a production supply that needs robust communications and fault handling. Good option if you want native CAN and a more automotive-style ecosystem.
High-Voltage Power Stage Controller
Top Pick UCC256404 Texas Instruments
UCC256404 is the best starting point if you are building an efficient isolated AC-DC architecture, because an LLC front end is a practical way to reach 1 kW with good efficiency and manageable thermal stress.
Digikey $2.86 (922 in stock)
UCC28180 Texas Instruments
PFC controller for the front end, useful if you need a medical-grade AC input stage with high power factor and lower input harmonics. Commonly used in offline supplies and pairs well with an isolated downstream converter.
Digikey $2.02 (928 in stock)
UCC28950 Texas Instruments
Phase-shift full-bridge controller for high-power isolated conversion, appropriate when you need a robust 1 kW-class topology with good efficiency and transformer utilization. Strong fit for a custom production supply where the power stage is more important than simplicity.
Current Sense / Telemetry
Top Pick INA233AIDGSR Texas Instruments From our database
INA233AIDGSR is the best telemetry choice because it gives the MCU direct current, voltage, and power monitoring over I2C, which is ideal for supervisory control, logging, and fault detection in a production supply.
Digikey $3.92 Mouser
INA225AIDGKR Texas Instruments From our database
High-side current monitor with zero-drift architecture and selectable gain, useful for accurate current feedback in a noisy power system. Good for monitoring lower-voltage rails or auxiliary current paths, though its 36 V common-mode limit makes it unsuitable for the 4 kV output itself.
Temperature Sensor
Top Pick TMP112AIDRLR Texas Instruments From our database
TMP112AIDRLR is the best fit because it is already in the database, is easy to use over I2C, and is accurate enough for heatsink and enclosure protection in a 1 kW supply.
Digikey $1.12 (45,532 in stock) Mouser
MCP9808 Microchip Technology From our database
High-accuracy digital temperature sensor with a simple I2C interface, good for thermal monitoring in a medical-grade supply. Useful when you want straightforward firmware integration and reliable temperature thresholds.
TMP117 Texas Instruments
Very high accuracy digital temperature sensor, well suited to production thermal monitoring where calibration margin matters. Good choice if you want tighter thermal control around critical components.
CAN Bus
Top Pick TCAN332DR Texas Instruments
Top pick: TCAN332DR (Texas Instruments). Modern low-power CAN transceiver option with strong industrial pedigree, appropriate for robust CAN communication in a noisy power environment. Good choice if you want a current-generation alternative to the SN65HVD230 family.
Digikey $2.31 (2,954 in stock)
Power Supply
Top Pick LRS-1000-24 MEAN WELL AI suggestion - verify availability
LRS-1000-24 is the best practical starting point for the mains front end because it is a widely available 1 kW-class supply family and gives you a realistic basis for the rest of the high-voltage design, while the control electronics can be powered separately.
UHP-1000-24 MEAN WELL
Higher-end 1 kW class AC-DC supply family with better density and industrial pedigree, useful as a reference or subsystem in a production design. Appropriate when you need a robust mains front end and plan to do the final HV regulation separately.
Digikey $256.50 (134 in stock)
IRM-10-24 MEAN WELL
Compact auxiliary supply option for control electronics, not the main 1 kW path. Useful for generating isolated low-voltage rails for the MCU, CAN transceiver, and sensors.
Digikey $7.20 (3,113 in stock)

Compatibility Notes

  • The MCU, CAN transceiver, and I2C sensors all operate in the 3.3 V control domain, so keep the digital side at 3.3 V and avoid 5 V logic unless you add level shifting.
  • INA233AIDGSR and INA225AIDGKR are not suitable for directly measuring a 4 kV output; they are best used on auxiliary rails or low-voltage feedback paths. The main HV feedback will need a dedicated isolated sensing network and careful creepage/clearance design.
  • A 1 kW, 4 kV supply implies roughly 250 mA output current at full load, so the power stage, transformer, rectification, and thermal design are the dominant constraints, not the MCU.
  • If the CAN interface must be isolated from the high-voltage power domain, you will need an isolated CAN transceiver or digital isolator not listed in the current candidate set.

You'll Also Need

  • High-voltage transformer or custom magnetics for the 4 kV isolated output stage.
  • HV rectifiers, snubbers, bleeder resistors, output capacitors, and a proper constant-current feedback network rated for 4 kV.
  • Isolation components such as optocouplers or digital isolators for feedback and fault signaling if galvanic isolation is required.
  • EMI/EMC input filter, inrush limiting, fuse, MOV/TVS protection, and medical-grade leakage-current mitigation components.
  • Mechanical enclosure, heatsinks, insulation barriers, conformal coating, HV connectors, and creepage/clearance compliant PCB layout.
  • Safety certification work, test fixtures, and compliance validation for medical electrical equipment standards.
Estimated BOM Cost: $120-300 (based on live distributor pricing)
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Design Considerations

Medical Safety and Isolation
A 4 kV, 1 kW medical-grade supply is fundamentally a safety isolation problem first and a control problem second. You will need reinforced insulation, controlled creepage and clearance, and a clear separation between the mains/HV domain and the CAN/control domain. Plan the PCB stackup, slotting, and connector placement around the required isolation distances from the start, because retrofitting safety spacing late in the design is usually impossible.
Power Topology Choice
At 1 kW, efficiency and thermal management matter a lot, so an LLC or phase-shift full-bridge architecture is usually more realistic than a simple flyback or forward converter. The UCC256404 or UCC28950 class of controller is a better fit than a low-power controller because it supports a power stage that can actually survive continuous operation at this level. Expect transformer design, rectifier losses, and snubber tuning to dominate the first prototype cycle.
Output Regulation at 4 kV
Constant-current regulation at 4 kV cannot rely on ordinary low-voltage current-sense parts directly on the output. Use an isolated sensing strategy and keep the feedback loop bandwidth conservative enough to remain stable across transformer tolerance, load variation, and HV rectifier dynamics. The control loop should also include hard fault thresholds for arc detection, open-load, and overcurrent events.
CAN Reliability in a Noisy Supply
A 1 kW offline converter is an electrically noisy environment, so CAN wiring and transceiver placement need careful attention. Keep the CAN transceiver close to the connector, use proper termination, and add common-mode protection and ESD strategy at the board edge. Firmware should implement heartbeat supervision, command timeouts, and a safe default output state if CAN communication is lost.
Thermal and Derating Strategy
The TMP112AIDRLR should be used to monitor the hottest practical points such as the primary switch area, transformer core region, and secondary rectifier heatsink. In a 1 kW design, a 10 C rise in ambient can materially change efficiency and reliability, so derate output current as temperature increases rather than waiting for a hard shutdown. This improves field reliability and reduces nuisance trips.
Validation and Fault Testing
You should test startup, short-circuit, open-circuit, arc-like transients, brownout, and CAN loss-of-communication behavior before any compliance effort. Use a programmable load and isolated measurement equipment, and verify that the supply enters a safe state under every fault condition. For production, define pass/fail thresholds for output ripple, regulation, thermal rise, and fault recovery time.

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