Said to be the industry’s first highly integrated radiation-hardened by design (RHBD) motor control integrated circuit (IC), the LX7720 significantly reduces weight and board space relative to conventional discrete motor control circuits. By reducing the number of components on a system, developers can inspect and test fewer parts, while also minimising the physical points of potential failure due to a smaller number of connections and solder joints.
The controller combines four half-bridge N-channel Metal Oxide Semiconductor Field Effect Transistor (MOSFET) drivers, four floating differential current sensors, a pulse modulated resolver transformer driver, three differential resolver sense inputs, six bi-level logic inputs, power drivers via external Field Effect Transistors (FETs), loop control electronics for voltage or current control, position read-back (resolver, potentiometer, limit switches, etc.), fault detection and more into a single device.
The LX7720 serves as a mixed signal companion IC to the selected digital IC used in the application. Microchip’s Radiation Tolerant (RT) PolarFire and RTG4 Field Programmable Gate Array (FPGA) products and recently announced SAMRH71 radiation hardened microcontroller (MCU) are suitable companion chips. The LX7720 is MIL-PRF-38535 Class V and Class Q qualified and has already been adopted by customers to enable various motor control applications in space robotics and human-rated space programs. It is intended for spacecraft applications involving motor driver servo control, linear actuator servo control and for driving stepper, brushless direct current (BLDC) and permanent-magnet synchronous (PMSM) motors. The LX7720 offers radiation tolerance to 100 krad Total Ionization Dose (TID), 50 krad to Enhanced-Low-Dose-Rate-Sensitivity (ELDRS) exposure and is single event immune.
Microchip is also offering both hardware and software support. Hardware includes the LX7720 Daughter Board (DB) that interfaces with Microchip’s SAMRH71F20-EK Evaluation Kit. The DB can also connect to Microchip’s RTG4 FPGA Development Kit. These development platforms offer motor control software to allow application specific evaluation with the LX7720-DB.
