lc75411es Sanyo Semiconductor Corporation, lc75411es Datasheet - Page 28

• Manufacturer Part Number: lc75411es
• Description: Electronic Volume Controller For Car Audio Systems
• Manufacturer: Sanyo Semiconductor Corporation

(3) Zero-cross switching control method
(4) Zero-cross timer setting
(5) Cautions related to serial data transfer
The zero-cross switching control method consists of setting the zero-cross control bits to the zero-cross detection
mode (D36, D37 = 0), and specifying the detection blocks (D38, D39) before transmitting the data. These control bits
are latched immediately following data transfer, that is to say beforehand in sync with the falling edge of CE, so when
updating data of volumes, etc., it is possible to perform mode setting and zero-cross switching with one data transfer.
An example of control when updating the data of the volume block is shown below.
If the input signal becomes lower than the zero-cross comparator detection sensitivity, or if only low-frequency
signals are input, zero-cross detection continues to be impossible, and data is not latched during this time.
The zero-cross timer can set a time for forcible latch during such a status when zero-cross detection is not possible.
For example, to set 25 ms,
using T = 0.69CR and C = 0.033 µF,
we obtain
Normally, a value between 10 ms and 50 ms is set.
1. To ensure that the high-frequency digital signals transferred to the CL, DI, and CE pins do not spill over to the
2. The data format of the LC75411ES and 75411WS uses 8-bit addresses and 44-bit data. When sending data using
R=
analog signal block, either guard these signal lines with a ground pattern, or perform transmission using shielded
wires.
multiples of 8 (when sending 48 bits), use the method described in Figure 1.
Method for Receiving Data Using Multiple of 8 of LC75411ES and 75411WS
Zero-cross detection
D36
X
0
mode setting
0.69
Dummy data
X
25 10
0.033
D37
0
X
–3
10
X
–6
D38
1
D0
Volume block
Input switching control
1.1 M
setting
D1
D39
0
D2
LC75411ES, 75411WS
D3
Figure 1
D36
D37
D38
D39
D40
Test mode control
D41
X : don’t care
D42
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D43