Renesas — RX13T Microcontroller

Renesas has introduced a reference design for the control and driving of a low-voltage motor, demonstrating a way to develop a small motor-system control board which has a low bill-of-materials cost.

The design is based on the RX13T, a 32-bit microcontroller which is optimized for the control of a single brushless dc (BLDC) motor operating via field-oriented control. The RX13T has a built-in floating-point unit operating at 32 MHz, which improves software readability and reduces code size, as well as various built-in peripheral functions. The high level of integration in the MCU reduces the requirement for external components, and helps to simplify the board layout and reduce system size.

In particular, the RX13T includes PWM outputs configured for the UVW inputs to three HIP2211 high-frequency half-bridge drivers. The HIP2211 drivers feature a propagation delay of just 15 ns, and 2 ns propagation delay matching. Robust, the HIP2211 has a 115 V bootstrap voltage rating, and a -10 V rating on the high-side pin. The HIP2211 ICs drive the three-phase BLDC motor’s six RJK0651DPB MOSFETs.

In the reference design, the motor-control system is supported by an IPS2200 inductive position sensor, a contactless sensing device which provides real-time feedback on motor axle position without using Hall-effect sensors, which are often vulnerable to interference from stray magnetic fields.

Operating from an input voltage between 12 V and 36 V, an ISL85413 dc-dc converter regulates the voltage to the control system, with further regulation of the supply to the MCU implemented via an ISL80410 LDO.