Motor driver ICs
Spindle and loading motor driver for PD
BA6852FP
The BA6852FP is a motor driver IC developed for use in PD, CD-ROM and DVD applications. In addition to having a
conventional spindle motor driver, it includes a reversible motor driver for use with loading motors to allow easy system
construction.
Applications
PD, CD-ROM and DVD.
Features
1) Power save circuit (three-level switch) allows FG output in power save mode.
2) FGSW allows selection between either three-phase
composite output or single-phase output for the FG
output.
Absolute maximum ratings (Ta = 25C)
Recommended operating conditions (Ta = 25C)
792
3) The output voltage for the loading motor driver can be
set using the Vref pin.
Motor driver ICs
BA6852FP
Block diagram
793
Motor driver ICs
Pin descriptions
794
BA6852FP
Motor driver ICs
BA6852FP
Electrical characteristics (unless otherwise noted, Ta = 25C, VCC = 5V, VM1 = 12V, and VM2 = 12V)
795
Motor driver ICs
BA6852FP
Measurement circuits
(1) Measurement circuit resistance
(2)
Input / output table
Note: Forward EC < ECR
Reverse EC > ECR
796
Input voltage
H = 2.6V
M = 2.5V
L = 2.4V
Motor driver ICs
(3)
BA6852FP
Measurement circuits
ICC1
ICC2
ICC3
: Ammeter A1 value
IPS1 = 150µA
H1, H2, H3 = VCC / 2 (V)
H1, H2, H3 = VCC / 2 0.1 (V)
: Ammeter A1 value
PS = OPEN
H1, H2, H3 = VCC / 2 (V)
H1, H2, H3 = VCC / 2 0.1 (V)
: Ammeter A1 value
IPS3 = 150µA
H1, H2, H3 = VCC / 2 (V)
H1, H2, H3 = VCC / 2 0.1 (V)
IPSON
:
IPSOP
:
IPSOFF
:
IPS range for which all output pins
are open
(input conditions 1 to 6)
IPS range for only FG and the hall
bias operate
(input conditions 1 to 6)
PS range for which the output pins
are as in the Input / output table
(input conditions 1 to 6)
797
Motor driver ICs
BA6852FP
VHB
ITL
IHA
: Voltmeter V1value
VPS = 5V
IHB = 10mA
: (Voltmeter V2value) / 0.5
VPS = 5V
EC = 0V
(input conditions 1 to 6)
: With Hn = 4.0V, Hn = 2.5V,
the current that flows into Hn
With Hn = 2.5V, Hn = 4.0V,
the current that flows into Hn
(n = 1, 2, 3)
VHAR : Hall input voltage range for which
the output pin is as per the Input /
output table.
VINH : Hall input level for which the output
pin is as per the Input / output table.
| Hn Hn l
Hin = 2.5V
798
Motor driver ICs
BA6852FP
EC, ECR : Torque command operation
voltage range
ECOF± : Vary EC until ECR = 2.5V, then
Vary EC voltmeter V1 < 3mV.
This EC voltage range
(see operation notes (2)).
: Ammeter value when
ECIN
EC = 2V and ECR = 2.5V
: If the V1 value is V2 when
GEC
EC = 1.5V, and the V1
value is V3 when EC = 2.0V
GEC = {(V2 V3) / (2.0 1.5)} /
RNF (RNF = 0.5Ω)
VSBON
VSBOFF
: BRK pin voltage range when all
output pins are low.
: BRK pin voltage range when all
output pins are as per the Input /
output table.
799
Motor driver ICs
BA6852FP
VSWL : FGSW pin voltage range when
the hall input and FG output are
as per the table below.
VSWH : FGSW pin voltage range when
the hall input and FG output are
as per the table below.
VFGH : Voltmeter V1 value
(Input / output table, condition 2)
IFG = 10µA
FGSW = 0V
VFGL : Voltmeter V1 value
(Input / output table, condition 1)
IFG = 3mA
FGSW = 0V
800
Motor driver ICs
BA6852FP
VOH
VOL
: With the output measurement pin
made high level according to the
input conditions, the V1 value when
600mA flows from that pin.
: With the output measurement pin
made low level according to the
input conditions, the V2 value when
600mA flows from that pin.
VHYS : The voltage difference V3 between
H1 and H1 that switch the FG pin.
EC = 2.5V
FGSW = 0V
IVMD : Ammeter A1value
Output open (input conditions 1 to 6)
EC = 0V
801
Motor driver ICs
BA6852FP
ICC4
: Ammeter A1 value
IN1 = 5V, IN2 = 0V
ICC5
: Ammeter A1 value
IN1 = 5V, IN2 = 5V
VIH
: IN1 range for which OUT1 = High,
OUT2 = Low (IN2 = Low)
IN2 range for which OUT1 = Low,
OUT2 = High (IN1 = Low)
802
VIL
: IN1 range for which OUT1 = Low,
OUT2 = High (IN2 = High)
IN2 range for which OUT1 = High,
OUT2 = Low (IN1 = High)
IIH
: Ammeter A2 value when IN1 = 2V
Ammeter A3 value when IN2 = 2V
VCE
: Sum of V1 (the value when 200mA is
flowing from the output high level pin)
and V2 (the value when 200mA is
flowing to the output low level pin).
Motor driver ICs
BA6852FP
IREF
: Ammeter A1 value
IO = 100mA
VREF = 9V
VREF : VREF pin voltage range for which the
output voltage can be controlled
Operation notes
(1) Torque command
The RNF pin voltage with respect to the torque command
input (EC) is as follows.
The I / O gain GEC from the EC pin to the RNF (output
current) is determined by the RNF detector resistance.
GEC = 0.25 / RNF (A / V)
The torque limit current ITL is given by
ITL = 0.35 / RNF (A).
803
Motor driver ICs
BA6852FP
(2) Power save
The power save pin logic is as follows.
(3) Reverse rotation detector
The construction of the reverse rotation detector circuit
is shown in Fig. 17.
(1) Forward (EC < ECR)
The phase relationship between the hall input signals H2 and H3 is as shown in Fig.18, and the reverse rotation detector circuit does not operate.
(2) Reverse (EC > ECR)
The phase relationship between H2 and H3 is
opposite to that for forward rotation, and the reverse rotation detector circuit operates to switch the
output off and leave it in the open state.
Motor operation during reverse detection
When EC < ECR, forward rotation (right rotation)
When EC > ECR, reverse torque is applied to reduce speed (right rotation)
When the motor reverses, the reverse rotation detector operates, and the coil output is opened.
Free rotation in the reverse direction by inertia.
Stop
804
Motor driver ICs
(4)
BA6852FP
Input / output timing chart (forward rotation)
805
Motor driver ICs
(5)
BA6852FP
Short brake
When the BRK pin goes to high level, the upper-side output transistors (three phase) go off, and the lower-side output
transistors (three phase) go on.
(6) Hall input
The hall pins can be connected in series or parallel.
806
Motor driver ICs
(7) FG output switch
The relationship between the FG output switch pin and
the FG output is as follows.
(8) About the input pin applied voltage
Do not apply voltage to any of the other pins when the VCC
voltage is not being supplied to the IC. In addition, when
VCC is being applied, do not apply a voltage more than VCC
to any of the other pins.
BA6852FP
(10) VREF pin (output high level voltage setting)
The loading block output high level voltage can be set using the VREF pin voltage.
The output high level voltage VOH is given by the following
formula.
VOH = VREF ) IREF
R1 ) VBE (Q1) – VBE (Q3)
The VREF voltage that brings about the above formula is
up to VM2 – VCE (Q2) – VBE (Q3).
Do not apply a voltage of more than VM2 to the VREF pin.
Short the VREF pin to VM2 if you will not use it.
(9) Input pins
The loading input pin has a negative temperature characteristic, so when using it, give due consideration to the
temperature characteristics.
807
Motor driver ICs
BA6852FP
(11) Spindle and loading operation conditions
When IN1 or IN2 are high level, the spindle is off regardless of the PS pin input.
(12) Driver section ground (GND)
PGND (pin 14) is the driver section GND, and is not connected to the signal section GND. This is the motor current path, so take care with the PCB track width and arrangement on the PC board.
Electrical characteristics curves
808
(13) Thermal shutdown (TSD)
When the junction temperature reaches 175C (Typ.),
the motor output is opened. There is approximately 15C
(Typ.) of temperature hysteresis.
Motor driver ICs
BA6852FP
External dimensions (Units: mm)
809