7906 datasheet(235/531 Pages) RENESAS

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THREE-PHASE WAVEFORM MODE

7906 Group User’s Manual Rev.2.0

10-30

10.4 Three-phase mode 1

10.4.2 Operation in three-phase mode 1

Figure 10.4.4 shows a triangular wave modulation output example (three-phase mode 1).

➀ When an underflow occurs in the timer A3 counter, a timer A3 interrupt request is generated;

simultaneously, the one-shot pulse outputs of timers A0 through A2 are started. Also, the contents

of the three-phase output polarity set buffer are transferred to the output polarity set toggle flip-flop,

and then, the contents of the three-phase output polarity set buffer are reversed.

➁ The contents of the output polarity set toggle flip-flop are reversed at each falling edge of the one-

shot pulse output of timer A0/A1/A2. Simultaneously, the one-shot pulse of the dead-time timer is

output.

➂ Each of the positive and negative waveform outputs is not allowed to become “L” level from “H” level

until the reversed signal of the one-shot pulse output of the dead-time timer rises.

Repeat procedures from ➀ through ➂ for the three-phase waveform output control.

In the case of three-phase mode 1, the value of timer Ai ( i = 0 through 2) and the value of timer Ai1 are

counted alternately. Immediately after the count start in timer Ai, however, the value of the timer Ai register

is counted twice in succession. (It is a limitation to the case immediately after the count start in timer Ai.)

At this time, the timer Ai’s one-shot pulse becomes the same length twice in succession, also. Figure

10.4.5 shows an output example at start of three-phase mode 1.

For the triangular wave modulation output model (for one period), see Figure 10.3.6.

7906 Datasheet(PDF) 235 Page - Renesas Technology Corp