Microchip integrates rad-hard motor control with position sensing for satellites
More than 20 commonly used function have been integrated into a single chip by Microchip to reduce the size, weight and power (SWaP) on satellites and other space systems. The LX7720 radiation-hardened mixed signal motor controlled has been added to the Space System Manager (SSM) family.
It is claimed to be the industry’s first highly integrated radiation-hardened (rad-hard) by design motor control IC and to significantly reduce weight and board space relative to conventional discrete motor control circuits. Advantages of a reduced number of components in a system include fewer parts to inspect and test, and minimal physical points of potential failure because there are less connections and solder joints.
The LX7720 controller has been designed specifically for satellite manufacturers sensitive to board area and weight reduction. It consolidates essential functions for the motor control and position sensing circuitry required for robotics, multi-axis pointing mechanisms and precise motion control of optical elements. The LX7720 controller combines four half-bridge n-channel 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 FETs, loop control electronics for voltage or current control, position read-back (e.g. resolver, potentiometer, limit switches) and fault detection into a single device.
The LX7720 serves as a mixed signal companion IC to the digital IC selected for use in the application. (Microchip’s Radiation Tolerant (RT) PolarFire and RTG4 FPGAs and its SAMRH71 rad-hard microcontroller (MCU) are also companion chips, from a single supplier.)
The LX7720 is MIL-PRF-38535 Class V and Class Q-qualified and has already been adopted by customers for motor control applications in space robotics and human-rated space programmes, 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.
Hardware support for the LX7720 includes the LX7720 daughter board (LX7720-DB) which interfaces with the SAMRH71F20-EK evaluation kit. The daughter board 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.
The LX7720 is packaged in a 132-pin hermetic ceramic quad flatpack and Microchip also offers a sub-QML screened option in a 208-pin plastic package.
Samples and the LX7720-DB development boards are available.