PCA2000_2001

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Product data sheet

Rev. 08 — 23 August 2010

5 of 30

NXP Semiconductors

PCA2000; PCA2001

32 kHz watch circuit with programmable adaptive motor pulse

Therefore it is possible to program a larger energy gap between the pulses with step

detection and the strongest, not monitored, pulse. This might be necessary to ensure a

reliable and stable operation under adverse conditions (magnetic fields and vibrations). If

the watch works in the highest driving stage, the driving level jumps after the 4-minute

period directly to the lowest stage, and not just one stage lower.

To optimize the performance for different motors, the following parameters can be

programmed:

The enlargement pulse has a duty cycle of 25 % and a pulse width which is twice the

programmed motor pulse width. The repetition period for the chopping pattern is 0.98 ms.

Figure 4 shows an example of a 3.9 ms pulse.

Fig 4.

Possible modulations for a 3.9 ms motor pulse

43.75 %

37.5 %

DUTY CYCLE

50 %

56.25 %

62.5 %

68.75 %

75 %

81.25 %

100 %

mgw351

0.244 ms

0.122 ms

0.98 ms

0.98 ms

0.98 ms

0.98 ms