PIIPM50E06D004 datasheet(13/28 Pages) IRF

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PIIPM50P12B004

I27146 01/03

The “2406A” has three different serial interfaces

available: SCI, SPI, and CAN bus. In the PI-

IPM50P12B004 communication is made through

the asynchronous port (SCI) while four other

opto-isolated lines can be used for the SPI or for

the hall effect sensor interface. Maximum bit rate

for this asynchronous serial port is 2.5Mbps

while the SPI (synchronous) could reach

10Mbps. The choice of the SCI has been taken

for easy interfacing with a standard computer

serial port, the only component needed is a line

driver to adapt the RS232 voltage standard with

the RS422 at 3.3V used on this application.

In a standard Brushless motor application usually

1Mbps are far enough to transmit all information

needed for the torque reference updates and other

fault and feedback signals at a maximum frame

rate of 10kHz (100bits/frame), in this way the on-

board line driver let the application use long

connecting wires between the host and the

module, leaving the user the possibility of having

the PI-IPM displaced near the motor, e.g. in its

connecting box, thus avoiding long ad noisy three

phase cables between driver and load.

The JTAG port is the standard one, neither

isolation nor signal conditioning are provided

here and all signal, except the Tck-ret, are

directly connected from the related DSP pins to

the connector; however, due to the limited board

space, the connector used in not the standard 14

pins at two rows header, then an adaptor has to

be realized to connect it to the JTAG adapter

interface provided by Texas Instruments.

Last but not least is the ADC speed and load

characteristic: as the table shows the conversion

time is 500ns, in fact the 2406A DSP has a single

ADC handling, in time sharing, all 16 inputs,

then, using 6 inputs, the total conversion time,

which is a fixed delay to wait for before having

all data updated, is around 3.0

µs.

2. Flyback Power Supply

A flyback power supply for the floating stages is

provided in the EDB. As the block schematic on

page 2 shows, we have three 15V outputs for the

floating stages, isolated from each other at 1.5kV

minimum, and a single 5V and 3.3V output.

The 5V supplies all low voltage electronics and a

3.3V linear regulator is used to feed the DSP and

some analog and logic interfaces to it. This 5V

and 3.3V are directly referred to the DC bus

minus, so that all control circuitry is alternately at

one of the input lines potential, isolation is

provided at the DSP serial link level, then

avoiding all delays due to opto couplers insertion

between DSP and control logic. Note that also

the required 15V input voltage is referred to the

same DC bus minus and directly supplies the low

side gate drivers stages, the user should pay some

attention on how this supply line is realized in his

application. Just for completeness, the following

figure gives a possible solution to that that

doesn’t impact heavily on the user application.

Examples of power supply for PI-IPM

15V and 5V iso inputs

Normally a 5V power supply is already present,

for displays, electronics and micro processor, the

same 5V could be used for the 5V iso supply of

opto-couplers and line driver, the 15V could be

realized as an added winding in the secondary

side of the flyback transformer, the only care that

should be taken is in keeping its isolation from

the above mentioned 5V at the required level (at

least 1.5kV).

To avoid noise problems in the measuring lines

due to the commutating electronics during

normal functioning of the system, references are

kept separated. A 5V linear regulator, directly

supplied from the 15V input, is used to provide

the reference voltage to the current sensing

amplifying and conditioning components while a

precise op-amp, configured as a voltage follower,

PIIPM50E06D004 Datasheet(PDF) 13 Page - International Rectifier

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