BU64987GWZ Datasheet, PDF (7/25 Pages) Rohm – Bi-directional VCM driver for Auto focus

BU64987GWZ
Power Control
The host is able to put the driver in standby mode as well as enable/set the output to Hi-Z via 2-wire Serial Interface.
Standby mode is controlled by the PS bit and enable is controlled by the EN bit.
Please note that the PS bit is updated after the second byte is written/the second ACK from the driver is outputted during a
three byte write. The EN bit is updated after the third byte is written/the third ACK from the driver is outputted during a three
byte write. The third byte write is not required if only the standby (PS) setting is being updated.
Table 2. Power Control Register Data Format
Control Bit
Value
0
PS
1
EN
0
1
Description of Output Current Characteristics
Function
Driver in standby mode
Driver in operating
mode
Driver output is Hi-Z
Driver output is enabled
Figure 7. Description of Output Current Characteristics
The BU64987GWZ allows for configurable positive and negative output currents as well as the 0mA zero-cross reference
point (REF). The 0mA REF value is set by modifying the W[2:0]=0b011 register with an 8-bit DAC code offset by 2
LSBs. For example a REF value of 0x55 is normally shown as [0101 0101] or DEC 085, however after adding 2 zeros
to the LSB the binary value becomes [01 0101 0100] which corresponds to HEX 0x154 and DEC 340 for use in the
below equation. Based on the adjusted REF value, the maximum output current of the BU64987GWZ is calculated as:
𝐼𝑜_{𝑚𝑎𝑥}
=
( ²⁰⁰ )
1023
∗
(0𝑥3𝐹𝐹
−
𝑅𝐸𝐹)
[mA]
Equation 1. Maximum Output Current Calculation
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6. Oct.2016 Rev.001