BD7902CFS
Optical disc ICs
6CH Power Driver for
CD-ROM, DVD-ROM
BD7902CFS
BD7902CFS is a 6-channel driver IC that integrates all drivers necessary for CD-ROM, and DVD-ROM systems into a
single chip. The built-in 2-channel sled motor driver is used for the stepping motor. Low heat operation can be achieved
by applying the PWM driving system for sled and spindle motor drivers.
!Applications
CD-ROM, DVD-ROM
!Features
1) 3channel BTL driver, 2channel PWM driver and 3phase motor driver.
- ALL of the motor and actuator for CD-ROM, DVD-ROM etc.
2) These mode is able to be selected by the two control terminals.
- ON/OFF of loading, and other 5channels, brake mode select of spindle driver and standby mode.
3) Built-in triangular-wave generator.
4) Package SSOP-A54 has large power dissipation.
5) Built in thermal-shut-down circuit.
〈 Spindle driver 〉
• Efficient drive by current feedback PWM drive.
• Built in current limit, hall bias, short brake, FG output and reverse protection circuit.
• Low ON-Resistor. (RON=0.95Ω)
〈 Sled motor driver 〉
• Efficient drive by current feedback PWM drive.
• Built in 2channel for stepping motor.
〈 Actuator driver, Loading driver 〉
• Linear BTL drive system.
1/17
BD7902CFS
Optical disc ICs
!Absolute maximum ratings (Ta=25°C)
Parameter
POWER MOS
power suuply voltage
Symbol
Limits
Unit
SPVM1,2,SLRNF1,2
15∗1
V
VCC,SLVDD,AVM
15
V
DVCC
7
V
Preblock/BTL powerblock
power supply voltage
PWM control block
power supply voltage
Pd
2.6∗2
W
Operating temperature range
Topr
−35~+85
°C
Storage temperature
Tstg
−55~+150
°C
Power dissipation
∗1 POWER MOS output terminals (9, 11, 18, 34~37pin) is contained.
∗2 PCB (70mm×70mm×1.6mm glass epoxy) mounting.
Reduced by 20.8mW for each increase in Ta of 1°C over 25°C.
!Recommended operating conditions (Ta=25°C)
(Set the power supply voltage taking allowable dissipation into considering)
Parameter
POWER MOS Power supply voltage 1
Symbol
Min.
Typ.
Max.
Unit
SPVM1, 2
−
VCC∗3
−
V
POWER MOS Power supply voltage 2
SLRNF1, 2
−
SLVDD∗3
−
V
Preblock Power supply voltage
SLVDD, VCC
AVM
12
14
V
Power block Power supply voltage
AVM
4.3
5.0
VCC
V
PWM control block Power supply voltage
DVCC
4.3
5.0
6.0
V
Spindle output current
Iosp
−
1.2
2.5∗4
A
SL/FO/TR/LO output current
Ioo
−
0.5
0.8
A
∗3 Set the same supply voltage to VCC and SPVM1, 2 to SLVDD and SLRNF1, 2.
∗4 The current is guaranteed 3.0A in case of the current is turned on/off in a duty-ratio of
less than 1/10 with a maximum on-time of 5msec.
2/17
BD7902CFS
Optical disc ICs
DVCC
FCIN
TKIN
VCC
LDO+
LDO−
TKO+
TKO−
FCO+
FCO−
AVM
GND
GND
GND
GND
GND
AGND
SLO1+
SLO1−
SLO2+
SLO2−
SLGND
SLRNF2
SLRNF1
SLVDD
SLIN2
SLIN1
!Block diagram
54
53
52
51
50
49
48
47
46
45
44
43
42
41
40
39
38
37
36
35
34
33
32
31
30
29
28
47k
PRE
LOGIC
94k
−
TSD
47k
−
FF
94k
+
47k
PRE
LOGIC
47k
LIMIT
−
FF
+
OSC
+
47k
LEVEL
SHIFT
LEVEL
SHIFT
+
−
47k
LEVEL
SHIFT
LIMIT
Current
COMP
FF
FG
REVERSE
DETECT
Current
LIMIT
OSC
Polarity
COMP
PWM
OUT
94k
−
+
−
15k
+
3-phase
MATRIX
47k
15k
FG
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
HU−
HV+
HV−
HW+
HW−
HB
PGND1
U
SPVM1
V
GND
GND
GND
GND
GND
PGND2
W
SPVM2
SPRNF
FG
CTL1
CTL2
24
25
26
27
VC
3
LDIN
2
SPIN
1
HU+
HALL
BIAS
DGND
STBY/
BRAKE
CONTROL
3/17
BD7902CFS
Optical disc ICs
!Pin descriptions
Pin No.
Pin name
Pin No.
Pin name
1
HU+
Hall amp. U positive input
Function
28
SLIN1
Sled driver 1 input
Function
2
HU−
Hall amp. U negative input
29
SLIN2
Sled driver 2 input
3
HV+
Hall amp. V positive input
30
SLVDD
Sled driver PowerMOS pre-supply
4
HV−
Hall amp. V negative input
31
SLRNF1
Sled driver 1 current sense
5
HW+
Hall amp. W positive input
32
SLRNF2
Sled driver 2 current sense
6
HW−
Hall amp. W negative input
33
SLGND
Sled driver power ground
7
HB
Hall bias
34
SLO2−
Sled driver 2 negative output
8
PGND1
Spindle driver power ground 1
35
SLO2+
Sled driver 2 positive output
9
U
Spindle driver output U
36
SLO1−
Sled driver 1 negative output
10
SPVM1
Spindle driver power supply 1
37
SLO1+
Sled driver 1 positive output
Ground
11
V
Spindle driver output V
38
AGND
12
GND
GND
39
GND
GND
13
GND
GND
40
GND
GND
14
GND
GND
41
GND
GND
15
GND
GND
42
GND
GND
16
GND
GND
43
GND
GND
17
PGND2
Spindle driver power ground 2
44
AVM
Actuator driver block power supply
18
W
Spindle driver output W
45
FCO−
Focus driver negative output
19
SPVM2
Spindle driver power supply 2
46
FCO+
Focus driver positive output
20
SPRNF
Spindle driver current sense
47
TKO−
Tracking driver negative output
21
FG
Frequency generator output
48
TKO+
Tracking driver positive output
22
CTL1
Driver logic control input 1
49
LDO−
Loading driver negative output
23
CTL2
Driver logic control input 2
50
LDO+
Loading driver positive output
24
SPIN
Spindle driver input
51
VCC
25
DGND
PWM block pre-ground
52
TKIN
Tracking driver input
26
LDIN
Loading driver input
53
FCIN
Focus driver input
27
VC
Reference voltage input
54
DVCC
PWM block control power supply
BTL pre and Loading power supply
∗ Positive/negative of the output terminals are determined in reference to those of the input terminals.
4/17
BD7902CFS
Optical disc ICs
!Input output circuit
Three-phase motor driver output
19
Spindle driver current detection input
Hall bias
10
54pin
51pin
18
11
7
20
9
17
FG signal output
Hall signal input
54pin
54pin
54pin
54pin
1
2
3
4
5
6
21
BTL driver output FO, TK
PWM driver output SLED1, 2
BTL driver output LD
31 32
44pin
51pin
51pin
51pin
34
35
45
46
36
37
47
48
51pin
51pin
49
50
33
BTL driver input FO, TK, LD
PWM driver input SLED1, 2
51pin
PWM driver input Spindle
54pin
51pin
54pin
30pin
54pin
26
52
53
28
47kΩ
29
24
47kΩ
15kΩ
Control signal reference voltage input
Control signal input
54pin
51pin
10kΩ
54pin
15kΩ
50kΩ
50kΩ
50kΩ
27
22
50kΩ
23
50kΩ
5/17
BD7902CFS
Optical disc ICs
!Electrical characteristics
(unless otherwise noted, Ta=25°C, SLVDD=VCC=12V, DVCC=AVM=5V, VC=1.65V, SPRNF=0.33Ω, SLRNF=0.5Ω)
Parameter
Symbol
Min.
Typ.
Max.
Unit
Conditions
Circuit
Quiescent current 1
IQ1
−
12
20
mA
VCC (Loading OFF)
Fig1, 2
Quiescent current 2
IQ2
−
9
16
mA
VCC (Loading ON)
Fig1, 2
Quiescent current 3
IQ3
−
2.7
4.9
mA
DVCC
Fig1, 2
Stanby-on current 1
IST1
−
0.09
0.2
mA
VCC
Fig1, 2
Stanby-on current 2
IST2
−
0
0.1
mA
DVCC
Fig1, 2
VDZSL
15
0.8
(0.4)
−
40
1.0
(0.5)
1.8
65
1.2
(0.6)
2.3
mV
A/V
(V/V)
Ω
fosc
−
0.8
(0.4)
−
0.85
0.94
(0.47)
100
1.5
1.08
(0.54)
−
Ω
A
(V)
kHz
VHB
0.7
1.15
1.6
V
IHB=10mA
Circuit current
Sled driver block
Input dead zone (one side)
Input output gain
gmSL
Output ON resistor (upper)
RONUSL
Output ON resistor (lower)
RONLSL
Output limit current
ILIMSL
PWM frequency
Fig1, 2
SLRNF=0.5Ω
Fig1, 2
IL=500mA
Fig1, 2
IL=−500mA
Fig1, 2
SLRNF=0.5Ω
Fig1, 2
Fig1, 2
Spindle driver block 〈 Hall bias 〉
Hall bias voltage
Fig1, 2
Spindle driver block 〈 Hall amplifier 〉
Input bias current
IHIB
−
1
5
µA
Fig1, 2
Minimum input level
VHIM
50
−
−
mVPP
Fig1, 2
VHICM
1
−
4
V
Fig1, 2
20
2.4
(0.8)
−
50
3.0
(1.0)
0.6
90
3.6
(1.2)
1.0
mV
A/V
(V/V)
Ω
fosc
−
1.2
(0.4)
−
0.35
1.42
(0.47)
100
0.7
1.64
(0.54)
−
Ω
A
(V)
kHz
High voltage
VFGH
−
4.9
−
V
Low voltage
VFGL
−
0.1
−
V
Fig1, 2
VOFFT
−50
0
50
mV
Fig1, 2
Output saturation voltage "H"
VOHFT
−
0.45
0.8
V
IL=500mA
Fig1, 2
Output saturation voltage "L"
VOLFT
−
0.45
0.8
V
IL=−500mA
Fig1, 2
Voltage gain
GVFT
16.0
17.5
19.0
dB
Common mode input Range
Spindle driver block 〈 Torque control 〉
Input dead zone (one side)
VDZSP
Input output gain
gmSP
Output ON resistor (upper)
RONUSP
Output ON resistor (lower)
RONLSP
Output limit current
ILIMSP
PWM frequency
Fig1, 2
SPRNF=0.33Ω
Fig1, 2
IL=500mA
Fig1, 2
IL=−500mA
Fig1, 2
SPRNF=0.33Ω
Fig1, 2
Fig1, 2
Spindle driver block 〈 FG output 〉
100kΩ pull up to DVCC
Fig1, 2
Actuator driver block
Output offset voltage
Fig1, 2
This product is not designed for protection against redioactive rays.
6/17
BD7902CFS
Optical disc ICs
Parameter
Symbol
Min.
Typ.
Max.
Unit
Output offset voltage
VOFLD
−50
Output saturation voltage "H"
VOHLD
−
Output saturation voltage "L"
VOLLD
−
0.45
Voltage gain
GVLD
16.0
17.5
Input high voltage
VIH
2.0
−
Input low voltage
VIL
−
VC drop-muting
VMVC
VCC drop-muting
VMVCC
Conditions
Circuit
0
50
mV
1.1
1.4
V
IL=500mA
Fig1, 2
0.8
V
IL=−500mA
Fig1, 2
19.0
dB
Fig1, 2
−
V
Fig1, 2
−
0.5
V
Fig1, 2
0.4
0.7
1.0
V
Fig1, 2
3.4
3.8
4.2
V
Fig1, 2
Loading driver block
Fig1, 2
CTL1, CTL2
Others
This product is not designed for protection against radioactive rays.
7/17
BD7902CFS
Optical disc ICs
!Measurement circuits
OUT−
47
46
45
37
36
35
34
SLVDD
OUT+
48
SLRNF1
OUT−
49
SLED POWER
SUPPLY UNIT
SL2
OUT-A2
SLRNF2
OUT+
50
+
SL1
OUT-A1
AVM
OUT−
OUT−
+
A
FC
OUT-A3
OUT+
VCC
TK
OUT-A4
OUT+
LD
OUT-A5
OUT−
VINFC VINTK
OUT+
DVCC
32
31
30
VINSL2 VINSL1
A
IQDV
54
IQVC
53
52
51
44
43
42
41
40
39
38
33
29
28
47k
PRE
LOGIC
94k
−
TSD
47k
−
FF
94k
+
47k
PRE
LOGIC
47k
LIMIT
−
FF
+
OSC
+
47k
LEVEL
SHIFT
LEVEL
SHIFT
+
−
47k
LEVEL
SHIFT
LIMIT
Current
COMP
FF
REVERSE
DETECT
FG
Current
LIMIT
OSC
Polarity
COMP
PWM
OUT
94k
−
+
−
15k
+
3-phase
MATRIX
47k
15k
FG
STBY/
BRAKE
CONTROL
HALL
BIAS
1
IU+
2
A
3
IV+
+
HU+
4
A
5
IW+
+
HV+
7
6
8
9
10
11
12
13
14
15
16
17
2
SW-SP
18
19
20
21
A
+
+
+
24
25
26
27
IHB
A
IV−
23
A
HW+
+
IU−
22
A
IW−
+
VSPRNF
H−
VFG
V
V
100k
CTL1 CTL2 VINSP
VINLD VC
DVCC
1
SPRNF
SPVM
U
V
W
OUTSP
Fig.1
8/17
BD7902CFS
Optical disc ICs
SW-SL
SLVDD
SLRNF1
SLRNF2
SLED POWER SUPPLY
SW-SL
VSLRNF1
V
V
VSLRNF2
SLRNF2
SLRNF1
SLVM
V
47µH
OUT−
OUT+
OUT-A
VO SW-RL
RL
2
1
2
2
1
SW-IL
1
SW-IL
IL
IL
∗A3, A4 and A5 require no coil. (47µH)
OUTSP
U
V
W
2
1
2-V
2-U
RLSP
47µH
SW-RL
2
RLSP
1
SW-RL
RLSP
47µH
47µH
2-W
1
SW-IL
IL
Fig.2
9/17
BD7902CFS
Optical disc ICs
!Table of measure circuit switches position 1
(VCC=SPVM=SLVM=12V, DVCC=AVM=5V, VC=1.65V, RL (act) =8Ω, RL (SL) =8Ω+47µH, RL (SP) =2Ω+47µH,
SLRNF=0.5Ω, SPRNF=0.33Ω, H−=2.5V, HU+=2.6V, HV+=HW+=2.4V)
INPUT
Designation
CTL
SWITCH
Measure
point
Conditions
RL SP SL
IL
1
1
1
1
IQVC
L
1
1
1
1
IQVC
H
1
1
1
1
IQDV
L
1
1
1
1
IQVC
L
1
1
1
1
IQDV
H
H
2
1
1
1
∗1 Check VSLRNF with no output at VIN=VC±15mV
Check VSLRNF with output at VIN=VC±65mV
VSLRNF
H
H
2
1
1
1
See bellow
VSLRNF
2
2
ILSL=500mA
1
2
2
ILSL=−500mA
2
1
1
1
VSLRNF
2
1
1
1
VOSL+
VIN
1
2
IQ1
−
L
H
IQ2
−
H
IQ3
−
L
IST1
−
L
IST2
−
L
*1
gmSL
*2
RONUSL
3.3V
(0V)
H
H
1
1
RONLSL
0V
(3.3V)
H
H
1
ILIMSL
3.3V
(0V)
H
H
fosc
1.45
H
H
Circuit current
Sled driver block
VDZSL
lop
VRNF4/RNF
12V − VOSL + (−)
RON=
0.5A
RON=
OUT+ (−)
VOSL + (−)
0.5A
OUT+ (−)
Iosp
Iosl
VRNF1/RNF
Iop
VRNF3/RNF
VRNF2/RNF
Iosp or Iosl
SPRNF=0.33Ω
SLRNF=0.5Ω
VIN
VIN4
VIN3
VIN2
VIN1
Time
Iop...the peak current of Iosp or Iosl
Dead zone
∗2 Sled driver
VIN1=240mV, VIN2=140mV
VIN3=−140mV, VIN=−240mV
VSLRNF1 − VSLRNF2
) / 0.5Ω
240mV − 140mV
VSLRNF4 − VSLRNF3
gm (−) = (
) / 0.5Ω
240mV − 140mV
gm (+) = (
∗4 Spindle driver
VIN1=150mV, VIN2=100mV
VIN3=−100mV, VIN=−150mV
VSPRNF1 − VSPRNF2
) / 0.33Ω
150mV − 100mV
VSPRNF4 − VSPRNF3
gm (−) = (
) / 0.33Ω
150mV − 100mV
gm (+) = (
10/17
BD7902CFS
Optical disc ICs
!Table of measure circuit switches position 2
(VCC=SPVM=SLVM=12V, DVCC=AVM=5V, VC=1.65V, RL (act) =8Ω, RL (SL) =8Ω+47µH, RL (SP) =2Ω+47µH,
SLRNF=0.5Ω, SPRNF=0.33Ω, H−=2.5V, HU+=2.6V, HV+=HW+=2.4V)
Designation
INPUT
VIN
CTL
SWITCH
RL SP SL
Measure
point
Conditions
IL
1
2
H
H
1
1
1
1
IHB=10mA
H
H
1
1
1
1
Current flowing in each terminal at H−=2.5V,
HW+=2.7V (2.3V), HV=2.5V
IU+ (−),
IV+ (−),
IW+ (−)
Spindle driver block
〈 Hall bias 〉
VHB
1.65V
Pin 7
〈 Hall amplifier 〉
IHIB
1.65V
〈 Torque command 〉
VDZSP
∗3
L
H
2
1
1
1
∗2 Check VRNF with no output at VIN=VC±20mV
Check VRNF with output at VIN=VC±90mV
VSPRNF
gmSP
∗4
L
H
2
1
1
1
See 15 of 20
VSPRNF
RONUSP
3.3V
H
H
1
2
1
2
ILSP=500mA
RON = 12V − VOSP
0.5A
OUTU, V, W
RONLSP
3.3V
H
H
1
2
1
2
ILSP=−500mA
RON = VOSP
0.5A
OUTU, V, W
ILIMSP
3.3V
H
H
2
1
1
1
VSPRNF
fosc
1.85
H
H
2
1
1
1
VOSPU
VFGH
1.65V
H
H
1
1
1
1
HW+=2.4V
VFG
VFGL
1.65V
H
H
1
1
1
1
HW+=2.6V
VFG
〈 FG 〉
∗5 Condition of input
HU+
HV+
HW+
U
V
W
Condition
Measure point
2.4V
2.6V
2.6V
2.6V
2.4V
2.6V
Source
Hi-Z
Sink
IOSPU=500mA
VOSPU
Sink
Source
Hi-Z
IOSPV=500mA
VOSPV
2.6V
2.6V
2.6V
2.4V
2.4V
Hi-Z
Sink
Source
IOSPW=500mA
VOSPW
2.4V
Sink
Hi-Z
Source
IOSPU=−500mA
VOSPU
2.4V
2.4V
2.6V
2.4V
Source
Sink
Hi-Z
IOSPV=−500mA
VOSPV
2.4V
2.6V
Hi-Z
Source
Sink
IOSPW=−500mA
VOSPW
11/17
BD7902CFS
Optical disc ICs
!Table of measure circuit switches position 3
(VCC=SPVM=SLVM=12V, DVCC=AVM=5V, VC=1.65V, RL (act) =8Ω, RL (SL) =8Ω+47µH, RL (SP) =2Ω+47µH,
SLRNF=0.5Ω, SPRNF=0.33Ω, H−=2.5V, HU+=2.6V, HV+=HW+=2.4V)
Designation
INPUT
VIN
CTL
1
2
SWITCH
RL SP SL
Measure
point
Conditions
IL
Actuator driver block
VOFFT
1.65V
H
H
2
1
1
1
VOHFT
3.3V
(0V)
H
H
1
1
1
2
IL=500mA
5−OUT+ (−)
VOLFT
0V
(3.3V)
H
H
1
1
1
2
IL=−500mA
OUT+ (−)
GVFT
±0.25V
H
H
2
1
1
1
20log |(VO − VOFFT) / ±0.25)|
VO
VO
Loading driver block
VOFLD
1.65V
H
L
2
1
1
1
VOHLD
3.3V
(0V)
H
L
1
1
1
2
IL=500mA
12−OUT+ (−)
VOLLD
0V
(3.3V)
H
L
1
1
1
2
IL=−500mA
OUT+ (−)
GVLD
±0.25V
H
L
2
1
1
1
20log |(VO − VOFFT) / ±0.25)|
VO
VO
CTL1, CTL2
VIH
1.65V
L
L
2
1
1
1
Check active at "H"=2.0
IQVC
VIL
1.65V
H
H
2
1
1
1
Check stand-by at "L"=0.5
IQVC
VMVC
1.65V
H
H
1
1
1
1
Check all output at VC=0.7V
OUTPUT
VMVCC
1.65V
H
H
1
1
1
1
Check all output at VCC=3.8V
OUTPUT
CTL1, CTL2
!Circuit operation
1. Driver control terminal 1 and 2 (pin22 and pin23)
All the drivers and spindle-drive braking mode can be switched on/off by inputting combinations of H-level signal
(higher than 2V) and L-level signal (lower than 0.5V) to these terminals.
CTL1
(Pin22)
CTL2
(Pin23)
Spindle
Sled
Focus
Tracking
Loading
L
L
1)
H
L
2)
−
H
CTL1
(Pin22)
CTL2
(Pin23)
SPIN > VC
SPIN < VC
L
H
Forward-rotation mode
Reverse-rotation braking mode
3)
H
H
Forward-rotation mode
Short-circuit braking mode
4)
... ON
... OFF
1) Standby mode
The IC is brought into standby state, and its power dissipation can be limited.
2) Drivers muting
All the output channels except the loading are muted and their outputs are turn off.
12/17
BD7902CFS
Optical disc ICs
3) Reverse-rotation braking mode (spindle)
A reverse-rotation torque is applied when SPIN < VC.
Reverse-rotation is detected with SPIN input and Hall input. If the spindle detects reverse rotation when SPIN < VC,
all the outputs are shorted out to GND.
4) Short-circuit braking mode (spindle)
All the spindle driver outputs are shorted out to GND when SPIN < VC.
2. Input/output timing chart
HU+
HU−
FWD
HV+
HV−
HW+
HW−
SPIN
Vref
FWD
REV
FWD
SOURCE
U
Hi-Z
SINK
SOURCE
V
Hi-Z
SINK
SOURCE
W
Hi-Z
SINK
A B C D E F
) Forward
rotation
mode
G H I
J K L
) Reverse
rotation
brake
) Reverse
protect
) Short
brake
13/17
BD7902CFS
Optical disc ICs
Ι ) Forward-rotation mode
In this mode, the disc rotation is started and accelerated.
When forward-rotation signal inputs from the Hall elements to the positive spindle-drive input terminals
(SPIN > VC), the spindle-drive output terminals output forward torque signal.
SPIN > VC
Hall amplifier input (forward rotation)
HU+
HU−
HV+
HV−
HW+
HW−
U
V
W
A
L
H
L
H
H
L
Hi-Z
Source
Sink
B
L
H
H
L
H
L
Source
Hi-Z
Sink
C
L
H
H
L
L
H
Source
Sink
Hi-Z
D
H
L
H
L
L
H
Hi-Z
Sink
Source
Source
E
H
L
L
H
L
H
Sink
Hi-Z
F
H
L
L
H
H
L
Sink
Source
Hi-Z
Source=PWM
ΙΙ, ΙΙΙ ) Braking mode
In this mode, the disc rotation is decelerated and stopped.
〈 Reverse-rotation braking 〉
When the forward-rotation signal inputs from the Hall elements to the negative spindle-drive input terminals
(SPIN < VC), the spindle-drive output terminals output reverse torque signal.
SPIN < VC
Hall amplifier input (forward rotation)
HU+
HU−
HV+
HV−
HW+
HW−
U
V
W
G
L
H
L
H
H
L
Hi-Z
Sink
Source
H
L
H
H
L
H
L
Sink
Hi-Z
Source
I
L
H
H
L
L
H
Sink
Source
Hi-Z
J
H
L
H
L
L
H
Hi-Z
Source
Sink
K
H
L
L
H
L
H
Source
Hi-Z
Sink
L
H
L
L
H
H
L
Source
Sink
Hi-Z
Source=PWM
3. Hall inputs (pin 1 to 6) and Hall bias (pin 7)
(Spindle)
Hall elements can be connected either in series or in parallel. Set the Hall input voltage to 1.0 to 4.0V.
VCC
VCC
HU
HU
HV
HW
HV
HW
7pin
〈 Parallel connection 〉
7pin
〈 Series connection 〉
14/17
BD7902CFS
Optical disc ICs
4. Torque command (spindle: pin 24, sled motor: pin 28 and 29) / output current detection terminals (spindle: pin 20, sled
motor: pin 31 and 32)
The relation between the torque command input and the output current detection terminals input is expressed as
shown below:
SPRNF
SLRNF
FWD rotation
Dead zone +
Dead zone −
SPIN
SLIN1, 2
VC
The input-output gain (gm) and the output-limit current (ILIM) depend on the resistance of RNF (output current
detection resistor). Please refer to the following expression.
The gain to drive the spindle or the sled motor can be decreased by connecting a resistor in series to each input
terminal.
Gain expression
Spindle
Sled
Input-output gain gm (A/V)
1.0/RNF
0.5/RNF
Output-limit current Ilim (A)
0.47/RNF
0.47/RNF
Gain with the added resistor gm (A/V) 15k/{SPRNF×(Rin+15k)}
0.5×47k/{SLRNF×(Rin+47k)}
Rin : added series resistor
5. PWM oscillation frequency
The PWM oscillation for driving the spindle and sled is free running. The oscillating frequency is 100kHz (typ.).
6. Muting functions
a) VC-drop muting
When the voltage at VC terminal (pin 27) drops to a value lower than 0.7V (typ.), the outputs of all the channels are
turned off. Set the VC terminal voltage to larger than 1.0V.
b) VCC-drop muting
When the voltages at DVCC terminal (pin 54) and VCC terminal (pin 51) drop to lower than 3.8V (typ.), the outputs of
all the channels are turned off.
c) Over voltage protection circuit
When the voltages at VCC terminal (pin 51) drop to uper than 15.5V (typ.), the output of only the spindle block is
turned off.
7. Thermal-shutdown
A thermal-shutdown circuit (over-temperature protection circuit) is built in to prevent the IC from thermal breakdown.
Use the IC under the thermal loss allowed to the package. In case the IC is left running over the allowable loss, the
junction temperature rises, and the thermal-shutdown circuit works at the junction temperature of 175°C (typ.) (the
outputs of all the channels are turned off). When the junction temperature drops to 150°C (typ.), the IC start operating
again.
15/17
BD7902CFS
Optical disc ICs
!Application example
53
52
51
50
49
48
47
46
45
44
43
42
41
40
39
38
37
36
35
34
33
32
SLRNF1
SLRNF2
AVM=5V
SLED2
M
VCC=12V
54
SLED SLED
IN2
IN1
LOADING
SLED1
DVCC=5V
SLVM=12V
STM
FOCUS
TRACKING
TRACKING
FOCUS IN
IN
31
30
29
28
47k
PRE
LOGIC
94k
−
TSD
47k
−
FF
94k
+
47k
PRE
LOGIC
47k
LIMIT
−
FF
+
OSC
+
47k
LEVEL
SHIFT
LEVEL
SHIFT
+
−
47k
LEVEL
SHIFT
LIMIT
Current
COMP
FF
FG
REVERSE
DETECT
Current
LIMIT
OSC
Polarity
COMP
PWM
OUT
94k
−
+
−
15k
+
3-phase
MATRIX
47k
15k
FG
STBY/
BRAKE
CONTROL
HALL
BIAS
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
HALL3
HALL2
HALL1
FG
µ-COM
SPINDLE
5V
µ-COM
SPINDLE
IN
VC
LOADING
IN
SPRNF
SPVM=12V
Fig.3
!Operation notes
(1) Wiring for SPRNF and SLRNF
Considering the wiring resistance, connect each detecting resistor as close as possible to the current detection
terminals for the spindle drive SPRNF (pin 20) and the sled motor drive SLRNF 1 and 2 (pin 31 and 32) of the IC.
(2) Current detection reference voltage
The detection of current in the spindle and sled involves the detection of voltage between the detection resistances,
but as the reference voltage of internal circuit, the voltage applied to VCC (pin 51) is used by the spindle and that
applied to SLVDD (pin 30) by the sled.
For this reason, be sure to apply VCC (pin 51) to the spindle and SLVDD (pin 30) to the sled according to the
corresponding power supply voltages to prevent voltage differences.
16/17
BD7902CFS
Optical disc ICs
(3) Reverse-rotation braking
In the case of reverse-rotation braking from high speed rotation, pay good attention to reverse electromotive force.
Furthermore, fully check the voltage to be applied to the output terminal and consider the revolutions applied to the
reverse-rotation brake.
(4) Bypass capacitor
Please connect a bypass capacitor (0.1µF) across the supply voltage lines close to the IC pins.
(5) Supply fault, ground fault, and short-circuit between output terminals
Do not short-circuit between any output pin and supply pin (supply fault) or ground (ground fault), or between any
output pins (load short-circuit). When mounting the IC on the circuit board, be extremely cautions about the
orientation of the IC. If the orientation is mistaken, the IC may break down, and produce smoke in some cases.
POWER DISSIPATION : Pd (W)
!Electrical characteristic curves
3
2.6W
2
1
0
0
25
50
75
100
125
150
AMBIENT TEMPERATURE : Ta (°C)
∗ On less than 25.7% (percentage occupied by copper foil),
70×70mm2, t=1.6mm glass epoxy mounting.
Fig.4 Power dissipation
!External dimensions (Units : mm)
22.0±0.2
28
27
0.15±0.1
6.0±0.2
0.1
2.2±0.1
1
0.3Min.
4.0±0.2
13.4±0.3
11.4±0.2
54
0.8
0.36±0.1
0.1
SSOP-A54
17/17
Appendix
Notes
No technical content pages of this document may be reproduced in any form or transmitted by any
means without prior permission of ROHM CO.,LTD.
The contents described herein are subject to change without notice. The specifications for the
product described in this document are for reference only. Upon actual use, therefore, please request
that specifications to be separately delivered.
Application circuit diagrams and circuit constants contained herein are shown as examples of standard
use and operation. Please pay careful attention to the peripheral conditions when designing circuits
and deciding upon circuit constants in the set.
Any data, including, but not limited to application circuit diagrams information, described herein
are intended only as illustrations of such devices and not as the specifications for such devices. ROHM
CO.,LTD. disclaims any warranty that any use of such devices shall be free from infringement of any
third party's intellectual property rights or other proprietary rights, and further, assumes no liability of
whatsoever nature in the event of any such infringement, or arising from or connected with or related
to the use of such devices.
Upon the sale of any such devices, other than for buyer's right to use such devices itself, resell or
otherwise dispose of the same, no express or implied right or license to practice or commercially
exploit any intellectual property rights or other proprietary rights owned or controlled by
ROHM CO., LTD. is granted to any such buyer.
Products listed in this document use silicon as a basic material.
Products listed in this document are no antiradiation design.
The products listed in this document are designed to be used with ordinary electronic equipment or devices
(such as audio visual equipment, office-automation equipment, communications devices, electrical
appliances and electronic toys).
Should you intend to use these products with equipment or devices which require an extremely high level of
reliability and the malfunction of with would directly endanger human life (such as medical instruments,
transportation equipment, aerospace machinery, nuclear-reactor controllers, fuel controllers and other
safety devices), please be sure to consult with our sales representative in advance.
About Export Control Order in Japan
Products described herein are the objects of controlled goods in Annex 1 (Item 16) of Export Trade Control
Order in Japan.
In case of export from Japan, please confirm if it applies to "objective" criteria or an "informed" (by MITI clause)
on the basis of "catch all controls for Non-Proliferation of Weapons of Mass Destruction.
Appendix1-Rev1.0