ak5354 AKM Semiconductor, Inc., ak5354 Datasheet - Page 15

• Manufacturer Part Number: ak5354
• Description: Low Power 20bit ?? Adc With Pga
• Manufacturer: AKM Semiconductor, Inc.

ASAHI KASEI
MS0054-E-02
• About zero crossing operation
Comparator for zero crossing detection in the AK5354 has offset. Therefore, it is a possible that IPGA value is
changed by zero crossing timeout as zero crossing detection does not occur by a little offset of comparator.
For example, when Lch and Rch are in the state of IPGA = 30H, both channels are set to IPGA = 31H. And then
the only Lch completed zero crossing, Rch is waiting for zero crossing detection, zero crossing counter is reset
when IPGA is newly written 32H, zero crossing operation starts toward IPGA = 32H in state Lch = 31H, Rch =
30H. Internal IPGA value in the AK5354 has the registers of L/R channels independently, according to change
IPGA value independently, IPGA value of L/R channels may become a difference in level.
Therefore, if IPGA is written before zero crossing detection on zero crossing timeout, IPGA is keeping the same
value. When IPGA is finished by normal zero crossing timeout on IPGA value of L/R channels does not give a
difference in level, the change of IPGA should be written after zero crossing timeout cycle and over.
Internal zero crossing
operation completion flag
Lch Internal IPGA
Rch Internal IPGA
IPGA Register
WR[IPGA=31H]
Reset zero crossing timer
30H
30H
30H
Figure 11. About Zero Crossing Operation
Zero crossing
31H
30H
31H
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WR[IPGA=32H]
Reset zero crossing timer
32H
32H
32H
[AK5354]
2004/12