BU64291GWZ-TR_技术文档

Datasheet

Linear/PWM Constant Current

VCM Driver

BU64291GWZ

●General Description

●Key Specifications

PWM frequency:

The BU64291GWZ is designed to drive voice coil motors

(VCM) and operate with PWM to improve system power

efficiency or switch to linear control to improve system

noise. The driver includes ISRC (intelligent slew rate

control) to reduce mechanical ringing to optimize the

camera’s auto focus capabilities.

0.5 to 2 MHz

400 kHz(Typ.)

2.5 Ω(Typ.)

100 mA (Typ.)

- 25 to + 85 °C

Master clock:

Output ON resistance:

Maximum output current:

Operating temperature range:

●Package(s)

W(Typ.) x D(Typ.) x H(Max.)

0.77 mm x 1.37 mm x 0.33 mm

●Features

UCSP30L1

2.3 V (Min.) driver power supply

Selectable linear and PWM operational modes

Current source and sink output

10 bit resolution current control

ISRC mechanical ringing compensation

2-wire serial interface

Integrated current sense resistor

●Applications

Auto focus of Cell Phone

Auto focus of Digital still camera

Camera Modules

Lens Auto focus

Web, Tablet and PC cameras

●Typical Application Circuit

3.0 V

0.1 to 10 µF

1.8 V

VDD

Power Save

TSD & UVLO

VREF

ISOURCE

SCL

SDA

Output

Control

PWM / Linear

Current

VCM MTR

10 bit

DAC

2-wire serial

Master

LOGIC

POR

Control

ISINK

Current

Sense

GND

Figure.1 Typical Application Circuit

○Product structure：Silicon monolithic integrated circuit ○This product is not designed protection against radioactive rays

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●Pin Configuration

2

1

GND

VDD

A

B

C

ISINK

SDA

ISOURCE

SCL

Figure.2 Pin configuration (TOP VIEW)

●Pin Description

BALL

No.

BALL

Name

Function

A1

A2

B1

B2

C1

C2

GND

VDD

Ground

Power supply voltage

Current sink output

Current source output

Serial data input

ISINK

ISOURCE

SDA

SCL

Serial clock input

●Block Diagram

VDD

TSD & UVLO

Power Save

VREF

ISOURCE

Output

Control

PWM / Linear

Current

SCL

SDA

10 bit

DAC

LOGIC

POR

Control

ISINK

Current

Sense

GND

Figure 3. Block diagram

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●Absolute Maximum Ratings

Parameter

Symbol

VDD

VIN

Limit

- 0.5 to + 5.5

390^*2

Unit

V

Power supply voltage

Control input voltage (SCL, SDA)^*1

Power dissipation

V

Pd

mW

°C

mA

Operating temperature range

Junction temperature

Topr

- 25 to + 85

125

Tjmax

Tstg

Storage temperature range

- 55 to + 125

+ 200^*3

Output current

IOUT

*1

*2

*3

VIN are 2-wire serial interface input pins (SCL, SDA)

Reduced by 3.9 mW / °C over 25 °C when mounted on a glass epoxy board (50 mm × 58 mm × 1.75 mm; 8 layers)

Must not exceed Pd, ASO, or Tjmax of 125 °C

●Recommended Operating Ratings

Parameter

Symbol

VDD

Min.

Typ.

Max.

4.8

Unit

V

Power supply voltage

Control input voltage^*1

2-wire serial interface frequency

Output current

2.3

3.0

VIN

0

-

4.8

V

FCLK

IOUT

400

100^*4

kHz

mA

-

*1

*4

VIN are 2-wire serial interface input pins (SCL, SDA)

Must not exceed Pd, ASO

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●Electrical Characteristics ( Unless otherwise specified Ta = 25 °C, VDD = 3.0 V )

Limit

Parameter

Symbol

Unit

Conditions

Min.

Typ.

Max.

Power Consumption

Standby current 1

ICCST1

ICCST2

ICC

-

70

100

1.5

µA

PS bit = 0

DAC code = 0x000

Standby current 2

Circuit current

1.0

mA

Control Input (VIN = SCL, SDA)

High level input voltage

Low level input voltage

Low level output voltage

High level input current

Low level input current

Under Voltage Lock Out

UVLO voltage

VINH

VINL

VINOL

IINH

1.5

0

-

4.8

0.5

0.4

10

V

-

V

IIN = + 3 mA (SDA)

- 10

µA

Input voltage = 0.9 x VIN

Input voltage = 0.1 x VIN

IINL

10

VUVLO

MCLK

1.6

- 5

-

2.2

5

V

Master Clock

MCLK frequency

%

MCLK = 400 kHz

PWM Operation

2-wire serial adjustable

Default = 1 MHz^*5

PWM frequency range

FPR

0.5

-

2

MHz

10 Bit D/A Converter (for Controlling Output Current)

Resolution

DRES

DDNL

DINL1

DINL2

-

10

-

bits

LSB

Differential nonlinearity

Integral nonlinearity 1

Integral nonlinearity 2

Output Current Performance

Output maximum current

Zero code offset current

- 1

- 4

1

4

-

Linear operation

PWM operation

-

IOMAX

IOOFS

95

-

100

0

105

5

mA

DAC code = 0x3FF

DAC code = 0x000

Ron_Pch + RNF or

Ron_Nch + RNF

Output resistance

ROUT

-

2.5

3.5

Ω

*5

PWM frequency range : 500 kHz to 2 MHz. (50 kHz step)

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●Typical Performance Curves

170

150

130

110

90

170

150

PWM 500 kHz

Ta = + 25 ℃

130

110

90

Ta = + 85 ℃

PWM 2 MHz

Linear

PWM 1 MHz

Ta = - 25 ℃

70

VDD = 2.8 V

R = 24 Ω

L = 290 µH

50

Ta = + 25 ℃

30

0

20

40

60

80

0

20

40

60

80

Time (ms)

Figure 4. Output resistance (Ron_Pch + RNF)

Figure 5. Efficiency vs. Output current

100

90

80

70

60

50

40

30

20

10

0

Ta = - 25 ℃

Ta = + 85 ℃

Ta = + 25 ℃

VDD = 3.0 V

0

128 256 384 512 640 768 896 1024

DAC code

Figure 6. Output current vs. DAC code

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170

150

130

110

90

170

150

130

110

90

VDD = 3.0 V

Ta = + 25 ℃

VDD = 3.0 V

Ta = + 25 ℃

Direct

70

ISRC (slew_rate = 00b)

ISRC (slew_rate = 01b)

50

30

0

30

20

40

60

80

0

20

40

60

80

Time (ms)

Figure 7. Displacement vs. settling time (slew_rate = 00b)

Figure 8. Displacement vs. settling time (slew_rate = 01b)

170

VDD = 3.0 V

Ta = + 25 ℃

VDD = 3.0 V

Ta = + 25 ℃

150

130

110

90

Direct

130

110

90

70

ISRC (slew_rate = 10b)

50

ISRC (slew_rate = 11b)

50

30

0

20

40

60

80

0

20

40

60

80

Time (ms)

Figure 9. Displacement vs. settling time (slew_rate = 10b)

Figure 10. Displacement vs. settling time (slew_rate = 11b)

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●2-wire serial interface Format (Fast mode SCL = 400 kHz)

Write mode R/W = 0)

Output from Master

Output from Slave

（

Update

R/W

W2 W1 W0

M D9 D8 A D7 D6 D5 D4 D3 D2 D1 D0 A

S

0

1

0

A PS EN

Read mode

W2 W1 W0

S

0

1

0

1

A PS EN

M

A

※ ※

Update W (register address)

Write

CD9 CD8

CD7 CD6 CD5 CD4 CD3 CD2 CD1 CD0

0

nA

Read

P : stop signal

nA : non acknowledge

S : start signal

A : acknowledge

: Don't care

※

Register name

Setting item

Description

R/W

PS

Read/write mode

Serial power save

Driver output status

0 = Write mode (0x18 address), 1 = Read mode (0x19 address)

0 = Driver in standby mode(ISOURCE is Low), 1 = Driver in operating mode

0 = ISOURCE output is Low.

1 = Current output is active.

EN

If W2 W1 W0 ≠ 110b, then M = 0 = ISRC mode disabled, M = 1 = ISRC mode enabled

If W2 W1 W0 = 110b, then M = 0 = PWM output operation, M = 1 = linear output operation

M

Mode select

000b = Point C target DAC

001b = Actuator frequency settings/slew rate settings

010b = Point A target DAC

011b = Point B target DAC

100b = Step mode settings

101b = PWM settings

W2W1W0

Register address

110b = Point C target DAC

Register data

D9 to D0

Data bits

●Register Update Timing

PS : Register is updated during the 2^ndACK response during a 3 byte 2-wire serial command

EN : Register is updated during the 3^rdACK response during a 3 byte 2-wire serial command

Wx : Register is updated during the 2^ndACK response during a 3 byte 2-wire serial command

M

Dx

: Register is updated during the 3^rdACK response during a 3 byte 2-wire serial command

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●Register Map

Address

000

Bit

Bit Name

Function

Point C DAC code setting 1[9:0]

D[9:0]

D[9:8]

D[7:3]

D2

C_DAC1[9:0]

rf[4:0]

Resonant frequency setting[4:0]

001

D[1:0]

D[9:0]

D[9:8]

D[7:5]

D[4:0]

D[9:8]

D[7:2]

D[1:0]

D[9:0]

slew_rate[1:0]

A_DAC[9:0]

B_DAC[9:0]

Slew rate speed setting[1:0]

Point A DAC code setting[9:0]

Point B DAC code setting[9:0]

010

011

str[2:0]

stt[4:0]

Step resolution setting[2:0]

Step time setting[4:0]

100

PWM_f[5:0]

slew_slope[1:0]

C_DAC2[9:0]

PWM frequency setting[5:0]

101

110

Output voltage slope setting[1:0]

Point C DAC code setting 2[9:0]

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●Characteristics of the SDA and SCL Bus Lines for 2-wire Serial Interface ( Ta = 25 °C, VDD = 2.3 to 4.8 V )

STANDARD-MODE^*6

FAST-MODE^*6

Parameter

Symbol

Unit

Min.

0

Max.

Min.

0

Max.

Pulse width of spikes which must be suppressed by the

input filter

tSP

50

ns

µs

ns

µs

Hold time (repeated) start condition. The first clock

pulse is generated after this period.

tHD;STA

tLOW

4.0

4.7

4.0

4.7

0

-

0.6

1.3

0.6

0

-

Low period of the SCL clock

High period of the SCL clock

Set-up time for repeated START condition

Data hold time

-

tHIGH

-

tSU;STA

tHD;DAT

tSU;DAT

tSU;STO

tBUF

-

0.9

-

3.45

Data set-up time

250

4.0

4.7

-

100

0.6

1.3

Set-up time for stop condition

Bus free time between a stop and start condition

-

*6 STANDARD-MODE and FAST-MODE 2-wire serial interface devices must be able to transmit or receive at the designated speed.

The maximum bit transfer rates are 100 kHz for STANDARD-MODE devices and 400 kHz for FAST-MODE devices.

This transfer rates is based on the maximum transfer rate. For example the bus is able to drive 100 kHz clocks with FAST-MODE.

●2-wire Serial Interface Timing

tHIGH

SCL

SDA

tHD : DAT

tSU : DAT

tLOW

tSU : STA

tSU : STO

tHD : STA

tBUF

SDA

START BIT

STOP BIT

Figure 11. Serial Data Timing

Figure 12. Start and Stop Bit Timing

●Initialization Sequence ( Ta = 25 °C, VDD = 2.3 to 4.8 V )

Item

Symbol Min. Typ. Max. Unit

2-wire serial data start time ti2c;s

2-wire serial data stop time ti2c;p

15

-

µs

1.3

VDD

2-wire serial data

Input data

ti2c;p

ti2c;s

Figure 13. Timing Waveform Applying Power (VDD) Until Input of Serial Data

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●Power Dissipation

0.39 W

Ambient Temperature : Ta (°C)

(This value is not guaranteed value.)

Figure 14. Power dissipation Pd [W]

●I/O equivalence circuit

VDD

SCL

SDA

VDD

GND

SCL

SDA

ISOURCE

ISINK

VDD

ISINK

ISOURCE

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●Description of Functions

1) Controlling Mechanical Ringing

A voice coil motor (VCM) is an actuator technology that is intrinsically noisy due to the properties of the mechanical

spring behavior. As current passes through the VCM, the lens moves and oscillates until the system reaches a steady

state. The BU64291GWZ lens driver is able to control mechanical oscillations by using the integrated ISRC (intelligent

slew rate control) function. ISRC is operated by setting multiple control parameters that are determined by the intrinsic

characteristics of the VCM. The following steps illustrate how to best utilize ISRC to minimize mechanical oscillations.

Step A1 – Determining the Resonant Frequency of the VCM

Each VCM has a resonant frequency that can either be provided by the manufacturer or measured. The resonant

frequency of an actuator determines the amount of ringing (mechanical oscillation) experienced after the lens as

been moved to a target position and the driver output current held constant. To determine the resonant frequency,

f₀, input a target DAC code by modifying the 10 bit C_DAC1[9:0] value in register W2W1W0 = 000b that will target

a final lens position approximately half of the actuator’s full stroke. Take care to not apply too much current so that

the lens does not hit the mechanical end of the actuator as this will show an incorrect resonant period. In order to

start movement of the lens to the DAC code that was set in C_DAC1[9:0], the EN bit must be set to 1.

Figure 15. Actuator Displacement Waveform (ISRC Disabled)

The resonant frequency (Hz) of the actuator can be calculated with Equation 1 using the resonant period observed

in Figure 15.

f₀= (T)^-1… (1)

After calculating the correct resonant frequency, program the closest value in the W2W1W0 = 001b register using

the 5 bit rf[4:0] values from Table 1. When calculating the resonant frequency take care that different actuator

samples’ resonant frequencies might vary slightly and that the frequency tolerance should be taken into

consideration when selecting the correct driver resonant frequency value.

Table 1. f₀Settings (rf[4:0])

rf[4:0]

00000

00001

00010

00011

00100

00101

00110

00111

f₀

rf[4:0]

01000

01001

01010

01011

01100

01101

01110

01111

f₀

rf[4:0]

10000

10001

10010

10011

10100

10101

10110

10111

f₀

rf[4:0]

11000

11001

11010

11011

11100

11101

11110

11111

f₀

-

85 Hz

90 Hz

95 Hz

100 Hz

105 Hz

110 Hz

115 Hz

120 Hz

125 Hz

130 Hz

135 Hz

140 Hz

145 Hz

150 Hz

-

50 Hz

55 Hz

60 Hz

65 Hz

70 Hz

75 Hz

80 Hz

-

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Step A2 – Selecting the Autofocus Algorithm’s Target DAC Codes

The ISRC algorithm is a proprietary technology developed to limit the ringing of an actuator by predicting the

magnitude of ringing created by an actuator and intelligently controlling the output signal of the driver to minimize

the ringing effect. Due to the ringing control behavior of ISRC, it is unable to operate properly unless the lens is

floating (lens lifted off of the mechanical end of the actuator). As such the ringing control behavior is broken into

three separate operational areas in order to provide the most optimally controlled autofocus algorithm.

ISRC Mode

Direct Mode

Step Mode

C

B

A

0

DAC code

A: lens displacement = 0 µm

B: all lenses floating

C: final lens position

Figure 16. Lens Displacement vs. DAC Code

Figure 16 illustrates the different operational modes that control the autofocus algorithm. Due to ISRC requiring a

floating lens, points A and B need to bet set in order to create a floating condition. In order to simplify the code

sequence, it is possible to skip setting point A and instead only set point B, however if an optimized ringing control

method is preferred, point A corresponds to the maximum amount of current that can be applied to all VCM units

without floating the lens. Point B corresponds to the minimum amount of current that can be applied to the VCM so

that all actuator units are floating. It should be noted that the target DAC codes could vary between different

actuator units and that sufficient evaluation should be performed before selecting the point A and B target DAC

codes. Point C is the final lens target position determined by the level of focus required for the image capture.

The actuator manufacturer should be able to provide the required current for points A and B, however it is possible

to test these points by slowly increasing the 10 bit value of C_DAC1[9:0] and measuring the lens movement using

a laser displacement meter or some other device to measure lens displacement.

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2) Controlling the Driver

After following steps A1 and A2 to characterize the VCM performance, the following steps should be followed in order

to properly control the driver settings for optimized autofocus performance.

Step B1 – Setting Point A, B, and C DAC Codes

Points A, B, and C are defined by 10 bit DAC codes set with the following registers:

Location

Point C

Point A

Point B

Point C

W2W1W0 Register

DAC Code Location

C_DAC1[9:0]

A_DAC[9:0]

Description

000

010

011

110

Final lens position before image capture

Maximum output current without floating the lens

Minimum output current required to float the lens

Final lens position before image capture

B_DAC[9:0]

C_DAC2[9:0]

Although both C_DAC1[9:0] and C_DAC2[9:0] control the point C DAC code, the driver will only operate using the

most recently programmed point C DAC code from either C_DAC1[9:0] or C_DAC2[9:0]. Updating the point C

DAC code with two separate registers was implemented to help simply the coding process by allowing simple

toggling of the M bit to enable/disable ISRC as well as PWM operation.

Step B2 – Controlling Direct Mode

Direct mode is when the driver outputs the desired amount of output current with no output current control. The

time in which the lens reaches the position that corresponds to the amount of output current set by the 10 bit DAC

code is ideally instant, ignoring the ringing effects. If the driver is set so that the lens is moved from a resting

position to point C with direct mode, ringing and settling time will be at a maximum.

Direct mode is used either when M = 0 or when M = 1 and the present DAC code is less than the DAC code of

point A.

M = 0 = ISRC mode disabled

When ISRC mode is disabled by setting the M bit equal to 0, the lens will traverse to the DAC code set for point C

when the EN bit is set equal to 1.

M = 1 = ISRC mode enabled

The driver automatically uses direct mode if the present DAC code is less than the target DAC code corresponding

to point A. Therefore during ISRC operation when the autofocus sequence has been started by setting the EN bit

equal to 1, the driver will automatically decide to use direct mode to output current up to point A and then switch to

step mode before continuing the autofocus sequence.

Step B3 – Controlling Step Mode

Step mode is the control period in which the lens is moved by small output current steps. During step mode it is

possible to control the step resolution and step time in order to generate just enough output current to float the

lens with minimal ringing effects. Ringing can be better controlled by choosing a large value for the step time and a

small value for the step resolution with the trading off of a greater settling time. The step time and step resolution

should be chosen depending on the acceptable system limits of ringing vs. settling time.

Step mode is used when M = 1 and the present DAC code is in between point A and point B. Typically this mode is

only used during ISRC operation between point A and B, however it is possible to move the lens to point C using

only step mode if point B is set such that point C is only 1 DAC code greater than point B.

Step mode is controlled by the 5 bit step time, stt[4:0], and 3 bit step resolution, str[2:0], values stored in register

W2W1W0 = 100b.

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Table 2. Step Time Settings (stt[4:0])

stt[4:0]

00000

00001

00010

00011

00100

00101

00110

00111

Step Time

-

stt[4:0]

01000

01001

01010

01011

01100

01101

01110

01111

Step Time

400 µs

450 µs

500 µs

550 µs

600 µs

650 µs

700 µs

750 µs

stt[4:0]

10000

10001

10010

10011

10100

10101

10110

10111

Step Time

800 µs

stt[4:0]

11000

11001

11010

11011

11100

11101

11110

11111

Step Time

1200 µs

1250 µs

1300 µs

1350 µs

1400 µs

1450 µs

1500 µs

1550 µs

50 µs

850 µs

100 µs

150 µs

200 µs

250 µs

300 µs

350 µs

900 µs

950 µs

1000 µs

1050 µs

1100 µs

1150 µs

Table 3. Step Resolution Settings (str[2:0])

Step

Resolution

Step

Resolution

Step

Resolution

Step

Resolution

str[2:0]

000

str[2:0]

010

str[2:0]

100

str[2:0]

110

-

2 LSB

3 LSB

4 LSB

5 LSB

6 LSB

7 LSB

001

1 LSB

011

101

111

As mentioned in step A2, it is possible to skip step mode during ISRC operation if a simpler autofocus code

sequence is desired. If there is no issue with moving the lens to point B using direct mode, then the DAC code for

point A should be left equal to 0. Additionally if the point A register is not set after the driver is initialized, then the

driver will automatically move the lens to point B with direct mode since the default value for point A is 0.

Step B4 – Controlling ISRC Mode

ISRC mode is the control period in which the lens is already floating and the driver smoothly moves the lens based

on the proprietary behavior of the ISRC algorithm. ISRC operation keeps ringing at a minimum while achieving the

fastest possible settling time based on the ISRC operational conditions.

ISRC mode is used when M = 1 and the present DAC code is greater than the DAC code for point B. If the target

DAC code for point C is set so that the value is too large and will cause excess ringing, the point C DAC code is

automatically updated with a driver pre-determined value to minimize the ringing effect. When M = 1, the driver will

automatically switch between direct mode, step mode, and ISRC mode when the point A, B, and C DAC code

conditions are met. The condition for this automatic transitioning to occur is when the register values for point B

and point C are set to values other than 0 and then the sequence will start when the EN bit is set equal to 1.

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C

*

ISRC DAC codes –

the details of ISRC

operation are proprietary

B

ISRC DAC codes^*

ISRC mode

A

Step mode

Direct mode

0

Time (ms)

Start sequence

Figure 17. Three Mode Sequential Operation (Shown as DAC Codes)

0

Time (ms)

Sequence start point

Figure 18. Three Mode Sequential Operation (Shown as Lens Displacement)

Step B5 – Controlling the ISRC Settling Time

The settling time of an actuator is the time it takes for ringing to cease. The BU64291GWZ is able to control the

settling time by modifying the slew rate speed parameter, however care must be taken to balance settling time vs.

acceptable ringing levels. By increasing the slew rate speed there is the possibility to decrease the settling time

but the ability to control ringing is also decreased. Likewise if less ringing is desired then there is a possibility to

reduce the ringing levels by using a slower slew rate speed setting at the cost of longer settling times. The slew

rate speed can be set by modifying the 2 bit slew_rate[1:0] value in register W2W1W0 = 001b. Figure 19 shows

the relationship of slew rate speed vs. settling time.

移動量

〔um〕

slew_rate [1:0] = 11b

Slew_rate〔1:0〕=2'b11

Sslleeww__raratete[1〔:10:]0=〕=120'bb10

Slew_rate〔1:0〕=2'b01

slew_rate [1:0] = 01b

Slew_rate〔1:0〕=2'b00

slew_rate [1:0] = 00b

0

T_DAC〔9:0〕変更

T_DAC [9:0] update

Time (ms)

Time (Tmims)e

〔ms〕

Figure 19. Displacement vs. Settling Time

Table 4. Slew Rate Speed Settings (slew rate [1:0])

Slew Rate

Speed

Slew Rate

Speed

Slew Rate

Speed

Slew Rate

Speed

slew_rate[1:0]

00

slew_rate[1:0]

01

slew_rate[1:0]

10

slew_rate[1:0]

11

Slowest

Slow

Fast

Fastest

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Step B6 – DAC Code Update Timing Considerations

Settling time is controlled by the resonant frequency of the actuator and the driver’s slew rate speed setting.

Depending on the combination of these parameters, the settling time can be such that updating point C with a new

DAC code before the lens has settled at the original point C DAC code can adversely affect the settling time due to

increased ringing effects. Utilize the slew rate speed parameter in order to modify the settling time so that any

updates to the point C DAC code do not occur before the lens has settled.

Please review the following example based on an actuator with a resonant frequency of 100 Hz:

Table 5. Relationship Between Slew Rate Speed and Settling Time Based on a 100 Hz Actuator

f₀

slew_rate[1:0]

Settling Time

40 ms

00

01

10

11

24 ms

100 Hz

16 ms

12 ms

In this example the settling time of the actuator can vary by up to ± 5 % due to the internal oscillator (MCLK)

having a variance of ± 5 %. The settling time has a proportionally inverse relationship to the resonant frequency

and therefore the settling time can be estimated as:

Table 6. Relationship Between Slew Rate Speed and Settling Time Based on a General Resonant Frequency f₀’

f₀’

slew_rate[1:0]

Settling Time

00

01

10

11

40 × (100 / f₀’) ms

24 × (100 / f₀’) ms

16 × (100 / f₀’) ms

12 × (100 / f₀’) ms

f₀’ Hz

Note that the orientation of the camera module can affect the settling time due to the influence of gravity on the

lens.

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3) PWM Operation

The BU64291GWZ supports PWM operation with selectable 50 kHz PWM frequencies steps as well as PWM

waveform slope control. Traditional VCM drivers operate with constant current drive and as the market moves more

towards constant autofocus application use with video recording, camera power consumption concerns are becoming

apparent. It should be noted that implementing PWM control in a camera module subsystem is difficult due to the noise

generated by the PWM signal and the effect on image quality noise. As such there should be careful consideration

when designing a camera module subsystem for use with PWM signals and that the designer should closely consult

with the module maker, actuator manufacturer, and ROHM for design assistance. ROHM is able to provide design

suggestions as well as driver operational guidelines to help minimize the influence of PWM noise on image quality.

Step C1 – Operating the Driver with PWM

The driver is set to default operate in PWM mode with a switching frequency of 1 MHz and a PWM waveform

slope (slew slope) of MAX. The W2W1W0 = 110b register controls PWM or linear operation by modifying the M

bit. When modifying the W2W1W0 = 110b M bit, it is also possible to update the point C DAC code in register

W2W1W0 = 110b for quick autofocus target position changes.

M = 1 = linear operation

The point C DAC code is updated with the 10 bit C_DAC2[9:0] value stored in W2W1W0 = 110b. The driver will

either operate with direct mode or ISRC mode depending on the M bit value stored in any register W2W1W0 ≠

110b after the EN bit is set equal to 1.

M = 0 = PWM operation

The point C DAC code is updated with the 10 bit C_DAC2[9:0] value stored in W2W1W0 = 110b. The driver will

either operate with direct mode or ISRC mode depending on the M bit value stored in any register W2W1W0 ≠

110b after the EN bit is set equal to 1.

During driver operation it is possible to switch between linear and PWM operation by modifying the M bit and

setting the same or a new point C DAC code with the W2W1W0 = 110b register without resetting the lens to a

resting position. Values of the M bit which control direct mode or ISRC mode set by registers W2W1W0 ≠ 110b will

not be affected when updating the M bit for PWM or linear operation with W2W1W0 = 110b. The driver will begin

the autofocus sequence using either direct mode or ISRC mode when the EN bit is set to 1.

Step C2 – Setting the PWM Frequency

Although lower PWM frequencies result in optimized power efficiency, the BU64291GWZ allows for selectable

PWM frequencies to help minimize any image quality noise issues created by PWM operation. Generally higher

PWM frequencies result in slightly lower power efficiencies, however please choose the best PWM frequency for

power efficiency vs. image quality noise vs. RF desense performance.

The PWM frequency is set by modifying the 6 bit PWM_f[5:0] value in register W2W1W0 = 101b. Please note that

shaded cells in Table 7 are approximate reference values to be used for image noise evaluation. Only PWM

frequencies from 500 kHz to 2 MHz are guaranteed for PWM frequency accuracy. The default PWM frequency

after driver initialization is 1 MHz.

Table 7. PWM Frequency Settings (PWM_f [5:0])

PWM

Frequency

PWM

Frequency

PWM

Frequency

PWM

Frequency

PWM_f[5:0]

000000

000001

000010

000011

000100

000101

000110

000111

001000

001001

001010

001011

PWM_f[5:0]

001100

001101

001110

001111

010000

010001

010010

010011

010100

010101

010110

010111

PWM_f[5:0]

011000

011001

011010

011011

011100

011101

011110

011111

PWM_f[5:0]

100100

100101

100110

100111

1000 kHz

50 kHz

600 kHz

650 kHz

700 kHz

750 kHz

800 kHz

850 kHz

900 kHz

950 kHz

1000 kHz

1050 kHz

1100 kHz

1150 kHz

1200 kHz

1250 kHz

1300 kHz

1350 kHz

1400 kHz

1450 kHz

1500 kHz

1550 kHz

1600 kHz

1650 kHz

1700 kHz

1750 kHz

1800 kHz

1850 kHz

1900 kHz

1950 kHz

2000 kHz

1000 kHz

100 kHz

150 kHz

200 kHz

250 kHz

300 kHz

350 kHz

400 kHz

450 kHz

500 kHz

550 kHz

101000

101001

100000

100001

100010

100011

1000 kHz

111111

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Step C3 – Setting the PWM Waveform Slope

The slew slope parameter is used to modify the slope of the driver’s PWM voltage output signal. The slew slope

parameter is set by modifying the 2 bit slew_slope[1:0] value in register W2W1W0 = 101b. The default slew slope

setting after driver initialization is the High slope value.

slew_slope[1:0]=2'b00 or 2'b11

slew_slope [1:0] = 00b or 11b

Voltage

(V)

slew_slope [1:0] = 01b

slew_slope[1:0]=2'b01

slew_slope [1:0] = 10b

slew_slope[1:0]=2'b10

Time

Time (ms)

(ms)

Figure 20. PWM Waveform Slope Comparison

It is possible to help improve image quality noise by limiting the voltage overshoot of the PWM signal by setting the

slew slope value equal to 10b (Low) for the shallowest slope; however this is detrimental to power efficiency. For

optimum power efficiency the slew slope should be set equal to 00b or 11b (High). Please choose the best setting

for power efficiency vs. image quality noise.

Table 8. Slew Slope Settings (slew_slope [1:0])

Output

Voltage

Slope

Output

Voltage

Slope

Output

Voltage

Slope

Output

Voltage

Slope

slew_slope

[1:0]

slew_slope

[1:0]

slew_slope

[1:0]

slew_slope

[1:0]

00

High

01

Middle

10

Low

11

High

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●Operational Notes

1) Absolute maximum ratings

Use of the IC in excess of absolute maximum ratings such as the applied voltage or operating temperature range

(Topr) may result in IC damage. Assumptions should not be made regarding the state of the IC (short mode or open

mode) when such damage is incurred. The implementation of a physical safety measure such as a fuse should be

considered when there is use of the IC in a special mode where it’s anticipated that the absolute maximum ratings

may be exceeded.

2) Power supply lines

Regenerated current may flow as a result of the motor's back electromotive force. Insert capacitors between the

power supply and ground pins to serve as a route for regenerated current. Determine the capacitance based on of

all the characteristics of an electrolytic capacitor due to the electrolytic capacitor possibly losing some capacitance

at low temperatures. If the connected power supply does not have sufficient current absorption capacity,

regenerative current will cause the voltage on the power supply line to rise, which combined with the product and

its peripheral circuitry may exceed the absolute maximum ratings. It is recommended to implement a physical

safety measure such as the insertion of a voltage clamp diode between the power supply and GND pins.

3) Ground potential

Ensure a minimum GND pin potential in all operating conditions.

4) Heat dissipation

Use a thermal design that allows for a sufficient margin regarding the power dissipation (Pd) during actual

operating conditions.

5) Use in strong magnetic fields

Use caution when using the IC in the presence of a strong magnetic field as doing so may cause the IC to

malfunction.

6) ASO

When using the IC, set the output transistor for the motor so that it does not exceed absolute maximum ratings or

ASO.

7) Thermal shutdown circuit

This IC incorporates a TSD (thermal shutdown) circuit. If the temperature of the chip reaches the below

temperature, the motor coil output will be opened. The thermal shutdown circuit (TSD circuit) is designed only to

shut off the IC to prevent runaway thermal operation. It is not designed to protect the IC or to guarantee its

operation. Do not continue to use the IC after use of the TSD feature or use the IC in an environment where the its

assumed that the TSD feature will be used.

TSD ON temperature [°C]

(Typ.)

Hysteresis temperature [°C]

(Typ.)

150

20

8) Ground Wiring Pattern

When using GND patterns for both small signal and large currents, it is recommended to isolate the two ground

patterns by placing a single ground point at the application's reference point. This will help to alleviate noise in the

small signal ground voltage due to noise created by the ground pattern wiring resistance for large current blocks.

Be careful not to change the GND wiring pattern of any external components.

Status of this document

The Japanese version of this document is formal specification. A customer may use this translation version only

for a reference to help reading the formal version.

If there are any differences in translation version of this document formal version takes priority

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●Ordering Information

B U 6 4 2 9 1 G W Z

TR

Part Number

Package

GWZ: UCSP30L1

Packaging and forming specification

TR: Embossed carrier tape

●Physical Dimension Tape and Reel Information

UCSP30L1 (BU64291GWZ)

1PIN MARK

Lot No.

B7

Tape

Quantity

Embossed carrier tape

6,000 pcs / reel

TR

(The direction is the 1pin of

product is at the upper

right when you hold reel on

the left hand and you pull

out the right hand)

0.77±0.03

Direction of feed

S

0.06

S

6-φ0.20±0.05

0.05 A B

A

C

B

A

B

Direction of feed

A1 Pin

1

2

Reel

0.185±0.05

P=0.4

*Order quantity needs to be multiple of the minimum quantity.

(Unit:mm)

●Marking Diagram(TOP VIEW)

UCSP30L1 (BU64291GWZ)

Product Name

1PIN MARK

Lot No.

B7

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●Revision History

Date

Revision

001

Changes

6.Aug.2012

5.Oct.2012

New Release

002

Change tape and reel information (P.20)

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Notice

Precaution on using ROHM Products

1. Our Products are designed and manufactured for application in ordinary electronic equipments (such as AV equipment,

OA equipment, telecommunication equipment, home electronic appliances, amusement equipment, etc.). If you

intend to use our Products in devices requiring extremely high reliability (such as medical equipment ^{(Note 1)}, transport

equipment, traffic equipment, aircraft/spacecraft, nuclear power controllers, fuel controllers, car equipment including car

accessories, safety devices, etc.) and whose malfunction or failure may cause loss of human life, bodily injury or

serious damage to property (“Specific Applications”), please consult with the ROHM sales representative in advance.

Unless otherwise agreed in writing by ROHM in advance, ROHM shall not be in any way responsible or liable for any

damages, expenses or losses incurred by you or third parties arising from the use of any ROHM’s Products for Specific

Applications.

(Note1) Medical Equipment Classification of the Specific Applications

JAPAN

USA

EU

CHINA

CLASSⅢ

CLASSⅣ

CLASSⅡb

CLASSⅢ

2. ROHM designs and manufactures its Products subject to strict quality control system. However, semiconductor

products can fail or malfunction at a certain rate. Please be sure to implement, at your own responsibilities, adequate

safety measures including but not limited to fail-safe design against the physical injury, damage to any property, which

a failure or malfunction of our Products may cause. The following are examples of safety measures:

[a] Installation of protection circuits or other protective devices to improve system safety

[b] Installation of redundant circuits to reduce the impact of single or multiple circuit failure

3. Our Products are designed and manufactured for use under standard conditions and not under any special or

extraordinary environments or conditions, as exemplified below. Accordingly, ROHM shall not be in any way

responsible or liable for any damages, expenses or losses arising from the use of any ROHM’s Products under any

special or extraordinary environments or conditions. If you intend to use our Products under any special or

extraordinary environments or conditions (as exemplified below), your independent verification and confirmation of

product performance, reliability, etc, prior to use, must be necessary:

[a] Use of our Products in any types of liquid, including water, oils, chemicals, and organic solvents

[b] Use of our Products outdoors or in places where the Products are exposed to direct sunlight or dust

[c] Use of our Products in places where the Products are exposed to sea wind or corrosive gases, including Cl2,

H2S, NH3, SO2, and NO2

[d] Use of our Products in places where the Products are exposed to static electricity or electromagnetic waves

[e] Use of our Products in proximity to heat-producing components, plastic cords, or other flammable items

[f] Sealing or coating our Products with resin or other coating materials

[g] Use of our Products without cleaning residue of flux (even if you use no-clean type fluxes, cleaning residue of

flux is recommended); or Washing our Products by using water or water-soluble cleaning agents for cleaning

residue after soldering

[h] Use of the Products in places subject to dew condensation

4. The Products are not subject to radiation-proof design.

5. Please verify and confirm characteristics of the final or mounted products in using the Products.

6. In particular, if a transient load (a large amount of load applied in a short period of time, such as pulse. is applied,

confirmation of performance characteristics after on-board mounting is strongly recommended. Avoid applying power

exceeding normal rated power; exceeding the power rating under steady-state loading condition may negatively affect

product performance and reliability.

7. De-rate Power Dissipation (Pd) depending on Ambient temperature (Ta). When used in sealed area, confirm the actual

ambient temperature.

8. Confirm that operation temperature is within the specified range described in the product specification.

9. ROHM shall not be in any way responsible or liable for failure induced under deviant condition from what is defined in

this document.

Precaution for Mounting / Circuit board design

1. When a highly active halogenous (chlorine, bromine, etc.) flux is used, the residue of flux may negatively affect product

performance and reliability.

2. In principle, the reflow soldering method must be used; if flow soldering method is preferred, please consult with the

ROHM representative in advance.

For details, please refer to ROHM Mounting specification

Notice - GE

Rev.002

Daattaasshheeeett

Precautions Regarding Application Examples and External Circuits

1. If change is made to the constant of an external circuit, please allow a sufficient margin considering variations of the

characteristics of the Products and external components, including transient characteristics, as well as static

characteristics.

2. You agree that application notes, reference designs, and associated data and information contained in this document

are presented only as guidance for Products use. Therefore, in case you use such information, you are solely

responsible for it and you must exercise your own independent verification and judgment in the use of such information

contained in this document. ROHM shall not be in any way responsible or liable for any damages, expenses or losses

incurred by you or third parties arising from the use of such information.

Precaution for Electrostatic

This Product is electrostatic sensitive product, which may be damaged due to electrostatic discharge. Please take proper

caution in your manufacturing process and storage so that voltage exceeding the Products maximum rating will not be

applied to Products. Please take special care under dry condition (e.g. Grounding of human body / equipment / solder iron,

isolation from charged objects, setting of Ionizer, friction prevention and temperature / humidity control).

Precaution for Storage / Transportation

1. Product performance and soldered connections may deteriorate if the Products are stored in the places where:

[a] the Products are exposed to sea winds or corrosive gases, including Cl2, H2S, NH3, SO2, and NO2

[b] the temperature or humidity exceeds those recommended by ROHM

[c] the Products are exposed to direct sunshine or condensation

[d] the Products are exposed to high Electrostatic

2. Even under ROHM recommended storage condition, solderability of products out of recommended storage time period

may be degraded. It is strongly recommended to confirm solderability before using Products of which storage time is

exceeding the recommended storage time period.

3. Store / transport cartons in the correct direction, which is indicated on a carton with a symbol. Otherwise bent leads

may occur due to excessive stress applied when dropping of a carton.

4. Use Products within the specified time after opening a humidity barrier bag. Baking is required before using Products of

which storage time is exceeding the recommended storage time period.

Precaution for Product Label

QR code printed on ROHM Products label is for ROHM’s internal use only.

Precaution for Disposition

When disposing Products please dispose them properly using an authorized industry waste company.

Precaution for Foreign Exchange and Foreign Trade act

Since our Products might fall under controlled goods prescribed by the applicable foreign exchange and foreign trade act,

please consult with ROHM representative in case of export.

Precaution Regarding Intellectual Property Rights

1. All information and data including but not limited to application example contained in this document is for reference

only. ROHM does not warrant that foregoing information or data will not infringe any intellectual property rights or any

other rights of any third party regarding such information or data. ROHM shall not be in any way responsible or liable

for infringement of any intellectual property rights or other damages arising from use of such information or data.:

2. No license, expressly or implied, is granted hereby under any intellectual property rights or other rights of ROHM or any

third parties with respect to the information contained in this document.

Other Precaution

1. This document may not be reprinted or reproduced, in whole or in part, without prior written consent of ROHM.

2. The Products may not be disassembled, converted, modified, reproduced or otherwise changed without prior written

consent of ROHM.

3. In no event shall you use in any way whatsoever the Products and the related technical information contained in the

Products or this document for any military purposes, including but not limited to, the development of mass-destruction

weapons.

4. The proper names of companies or products described in this document are trademarks or registered trademarks of

ROHM, its affiliated companies or third parties.

Notice - GE

Rev.002

Daattaasshheeeett

General Precaution

1. Before you use our Pro ducts, you are requested to care fully read this document and fully understand its contents.

ROHM shall not be in an y way responsible or liable for failure, malfunction or accident arising from the use of a ny

ROHM’s Products against warning, caution or note contained in this document.

2. All information contained in this docume nt is current as of the issuing date and subj ect to change without any prior

notice. Before purchasing or using ROHM’s Products, please confirm the la test information with a ROHM sale s

representative.

3. The information contained in this doc ument is provi ded on an “as is” basis and ROHM does not warrant that all

information contained in this document is accurate an d/or error-free. ROHM shall not be in an y way responsible or

liable for any damages, expenses or losses incurred by you or third parties resulting from inaccuracy or errors of or

concerning such information.

Notice – WE

Rev.001


型号：	BU64291GWZ-TR
厂家：	ROHM
描述：	Voice Coil Motor Controller, 0.2A, PBGA6, 0.77 X 1.37 MM, 0.33 MM HEIGHT, ROHS COMPLIANT, UCSP-6 电动机控制
文件：	总24页 (文件大小：1072K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

BU64291GWZ-TR [ROHM]

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