Datasheet

2. Hardware Description

The YRMCKITRL78G14 starter kit is a single board motor control inverter, based on the new RL78/G14 series of

microcontrollers. The hardware includes a low-voltage 3-phase MOSFET power stage, the MCU control system, the

switching power supplies and the communications / debugging / programming interface.

To maximise the flexibility of the demonstration board, the following features are included:

 A complete 3-phase inverter on-board with a low voltage motor, so it becomes easy to test the sensor-less

algorithm on the RL78G14.

 Two RL78/G14 devices can be supported by the board

o The default is the 100pin device (R5F104PJAFB)

o 64pin device (R5F104LEAFB)

o The pin out of both RL78G14 devices are brought out to connectors JPUP1, 2, 3 and 4

 USB Communications, Debugging and Programming interface via the uPD78F0730 USB MCU.

 Connectors for hall sensors and encoder connections

 Connection for an external power supply

 On board power supply generation from either the USB or external supplies

 A user “patch area” for external signal conditioning or use of other motor control algorithms

 Sample BLDC Motor

 External power stage interface.

The default device mounted on the board is the 100pin RL78/G14 device. If required this device can be removed and a

64pin RL78/G14 device fitted

The Communication/Debugging interface allows the user to control the inverter through the graphical user interface

(GUI), or to program the RL78/G14 with either the Renesas Flash Programmer or download and debug the motor

control program with the development IDE debugger. This interface uses the PC USB power supply.

When using external programming or debugging tools it is possible to fully isolate the communications interface to

avoid possibilities of electrical damage, especially when using the external power stage interface

The board can be fully powered either from the PC USB interface, or from an external power supply.

When the USB power is used, a step-up converter is used to obtain the inverter VBUS voltage necessary to generate the

voltages for the main board and the motor. In this mode the main system is not isolated from the PC and the current

available for the motor drive is limited to approximately 300mA.

When an external power supply is used the main board is fully isolated from the PC. The power for the motor is rated at

48Vdc @3A. It may be possible to supply more motor current, but it will be necessary to provide cooling for the

inverter stage power MosFets in order to keep the temperature of the power MosFets at around 60

The internal power supplies (logic and for the driving system) are obtained through two step-down switching regulators,

in order to reduce heating and power consumption.

A patch area was added to allow the user to make hardware modifications/adjustments as necessary. This area can also

be used to support alternative motor drive algorithms, such as sensorless BLDC drive.

Please refer to the schematics for the details of the full hardware implementation.