IRMCS3043

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have negative DC bus ground and it is necessary to isolate the scope when waveforms are measured and/or to isolate

the FS2 debugger when debugging is conducted.

2.3

IRMCF343

2.3.1 Power

IRMCF343 requires 3.3V and 1.8V. VDD1 is 3.3V used for I/O and VDD2 is 1.8V for digital logic. AVDD is

1.8V for analog and PLLVDD is for PLL. Only one source of 1.8V is shared in IRMCS3043 system. Typical

current value for 1.8V is less than 100 mA.

2.3.2 Crystal

A 4 MHz crystal is used to generate the system clock. The actual system frequency is adjustable by changing the Phase

Locked Loop configuration through Special Function Registers. For more information regarding clock, please refer to

the IRMCF34x and IRMCF37x User’s Guide.

2.3.3 Reset Circuit

IRMCF343 doesn’t require external RC circuit for reset. The reset switch is used when the JTAG debugger is started.

For more information regarding reset, please refer to the IRMCF34x and IRMCF37x User’s Guide.

2.3.4 EEPROM

Boot load takes place at power-up to load 8051 code and MCE code from an external EEPROM to internal RAM of

IRMCF343. EEPROM can be written using the MCEDesigner tool.

2.3.5 Digital I/O

Most of the digital I/O’s are connected to header J8 for the user’s convenience.

2.3.6 Analog Output

Analog D/A output channels are connected to header J6 for ease of use.

2.3.7 Motor Single-Shunt Current Feedback

IRMCF343 contains an Operational Amplifier for the single shunt motor current reconstruction circuit. Resistors and

capacitors for the amplifier circuit are placed very close to the pins. Note that, to provide better current feedback, there

is a separate trace from the shunt resistor instead of sharing a plane with negative DC bus ground.

2.3.8 PFC Current Feedback

IRMCF343 contains an Operational Amplifier for PFC current feedback. The PFC current feedback signal is

obtained through a shunt resistor that is in series with the PFC inductor and located at the negative DC bus side.

Resistors and capacitors for the amplifier circuit are placed very close to the pins. Note that, to provide better current

feedback, there is a separate trace from the shunt resistor instead of sharing a plain with negative DC bus ground.

2.3.9 AC Input Voltage Feedback

IRMCF343 contains an Operational Amplifier for AC input voltage feedback which is mainly used for PFC control.

The AC input voltage signal is obtained through a proprietary differential amplifier circuit and control logic that is

embedded inside of the IRMCF343 IC, together with a few external resistors and capacitors.

2.3.10 DC Bus Voltage Feedback

The DC bus voltage feedback is used in both motor control and PFC control. This is implemented through a voltage

divider circuit, and the scaled-down analog signal is fed into an ADC input pin (AIN0) of IRMCF343.

2.4

Input Diode Bridge Rectifier

One piece of IR25XB08H diode bridge rectifier is mounted on a heat sink under the board.