Philips TDA5149G Datasheet

INTEGRATED CIRCUITS

DATA SH EET

TDA5149G

12 V Voice Coil Motor (VCM) driver and spindle motor pre-driver combination chip

Product speciﬁcation File under Integrated Circuits, IC11

1996 May 06

Philips Semiconductors Product speciﬁcation

12 V Voice Coil Motor (VCM) driver and spindle motor pre-driver combination chip

FEATURES General features

• Single-chip voice coil motor driver and spindle motor pre-driver

• Internal voltage reference generator

• Programming of timing parameters via the serial bus

• Control of sleep, brake and disable modes for both the

VCM and spindle via the serial bus

• Temperature monitor circuit

• General purpose uncommitted operational amplifier.

Voice coil motor driver

• On-board full-bridge power DMOS driver with low R

• Class AB linear amplifier with no dead zone

• Adjustable gain and bandwidth

• Retract circuit operating at power-down.

Spindle motor pre-driver

• Designed to drive external N-channel power MOSFETs for brushless, sensorless DC motors

• Internal or external commutation control

• Digital commutation timing

• Average motor supply current control with Pulse Width

Modulation (PWM)

• Soft switching under PWM control

• Spindle brake after park at power-down.

DSon

APPLICATIONS

• 12 V high-performance hard disk drives.

GENERAL DESCRIPTION

The TDA5149G is a combination of a voice coil motor driver and a spindle motor pre-driver, capable of operating 12 V high-performance hard disk drives.

The device integrates a spindle pre-driver that drives three external N-channel power MOSFETs in order to drive a three-phase brushless, sensorless DC motor in full wave mode. In the normal mode, commutations are generated from the internal Back EMF (BEMF) sensing circuitry. Commutations, however, can also be generated from an external source, thereby providing the possibility of driving the motor in the stepper-motor mode.

The VCM driver is a linear transconductance amplifier capable of handling currents up to 1.65 A. It allows external adjustment of the gain and compensation. The TDA5149G also contains two drivers for a latch that secures the heads in the event of power-down.

To control functions such as park, brake, sleep or disable and to program the different timing parameters, the TDA5149G is provided with a three-wire serial port. A high precision voltage monitor is also included, for both 5 and 12 V power supplies. Finally, the IC contains a temperature monitor circuit and an uncommitted operational amplifier connected to VDD, which can be used freely within the application. The device is contained in a LQFP64 package with 4 pins connected to the lead frame for improved heat dissipation.

TDA5149G

QUICK REFERENCE DATA

SYMBOL PARAMETER CONDITIONS MIN. TYP. MAX. UNIT

DDD

DDA1

oVCM

DSon

ORDERING INFORMATION

TYPE

NUMBER

TDA5149G LQFP64 plastic low proﬁle quad ﬂat package; 64 leads; body 10 × 10 × 1.4 mm SOT314-2

1996 May 06 2

general supply voltage (pin 54) 10.8 12.0 13.2 V digital supply voltage (pin 55) 4.5 5.0 5.5 V analog supply voltage (pin 27) 4.5 5.0 5.5 V voice coil motor output current − − 1.65 A VCM power DMOS total on-resistance

(including leads and bond wires)

NAME DESCRIPTION VERSION

Tj= 25 °C − − 0.65 Ω Tj= 125 °C − − 1.1 Ω

PACKAGE

Philips Semiconductors Product speciﬁcation

Fig.1 Block diagram of the spindle part.

handbook, full pagewidth

MGE657

SAWTOOTH

OSCILLATOR

SERIAL

PORT

VPARK VCM_CONT1 VCM_CONT2 VGAINSEL SLEEP

COMMUT. DELAYS SBRAKE

SDISABLE SPINMODE COMMCLOCK

INIT

TRIGGER

CSS2 dis

SPWM comp 1

SPWM comp 2

CSS2 short CSS1 dis

CSS1 short LOOP1 select

CHARGE

PUMP

BRAKE DELAY

CSS1

CSS2

STOSC

SCANTEST

SCANOUT

SENABLE

SDATA

SCLOCK

CLOCK

MOT1

7 MOT2

MOT0

MOT3

ISPIN

13 14

SPINSENSEH SPINSENSEL

63 62

CAPX2

CAPX1

12 V

CLAMP

to the VCM

MOT1

MOT2

MOT3

3 kΩ

1 kΩ

3 kΩ

from the

PWM DAC

sense

CAPY

IDRIVE 12

BRAKEPOWER

BRAKEDELAY

AGND

DGND 64

DDA1

DDD

from the

POR circuit

to the

LATCH

to the

VCM

DIGITAL

CONTROL

RPOS

20 SICOMP

18 SINTIN

15 SISENS

5×

INTG

COMP

BEMF comp 1

BEMF comp 2

BEMF comp 3

DRIVER

COMP

0.4 V

LACTIVE

LHOLD

TDA5149G

1 2 3 4 5

BLOCK DIAGRAMS

12 V Voice Coil Motor (VCM) driver and spindle motor pre-driver combination chip

TDA5149G

1996 May 06 3

Philips Semiconductors Product speciﬁcation

Fig.2 Block diagram of the VCM and RESET circuits.

handbook, full pagewidth

MGE656

FOLLOWER

PREAMP

PARK

CIRCUITRY

SENSE

BUFFER

REFERENCE

CURRENT

GENERATOR

REFERENCE

VOLTAGE

GENERATOR

LATCH

CIRCUITRY

LACTIVE LHOLD

from the

serial port

TEMPERATURE

SENSOR

POWER-

ON RESET

GENERATOR

OPAMP

to the PARK circuit

COMP

+5 V

+12 V

+12 v

from the

serial port

from the

POR circuit

comp

CMIN2

CMIN1

CMSENSOUT

VCM

ref

ref(o)

ref

POR12

ADJ

POR5

ADJ

VCM_CONT1 VCM_CONT2

AMPIN−

AMPIN+

AMPOUT CLAMP

PGND1

DDV

CM+

CM−

PGND2

CMSENSEL

CMSENSEH

latch

LATCHACTIV

LATCHHOLD

TEMPMON

RESETPRESETA

POR

DELAY

26 35 34

50 46

100 nF

from the spindel

27 Ω

100 nF

27 Ω

in2

in1

VCM input

VCM

reference

input

TDA5149G

disable

park

brake

GAINSEL

CMref

20 kΩ

23 kΩ

50 kΩ

10 kΩ

50 kΩ

−

+5 V

+12 V

12 V Voice Coil Motor (VCM) driver and spindle motor pre-driver combination chip

TDA5149G

1996 May 06 4

Philips Semiconductors Product speciﬁcation

12 V Voice Coil Motor (VCM) driver and spindle motor pre-driver combination chip

PINNING

SYMBOL PIN I/O DESCRIPTION

CAPY 1 I/O charge pump capacitor MOT0 2 I motor centre tap input H1 3 O driver output to gate of upper power FET 1 MOT1 4 I back EMF comparator input 1 L1 5 O driver output to gate of lower power FET 1 H2 6 O driver output to gate of upper power FET 2 MOT2 7 I back EMF comparator input 2 L2 8 O driver output to gate of lower power FET 2 H3 9 O driver output to gate of upper power FET 3 MOT3 10 I back EMF comparator input 3 L3 11 O driver output to gate of lower power FET 3 IDRIVE 12 I adjustment for output stage drive current SPINSENSEH 13 I positive spindle sense ampliﬁer input SPINSENSEL 14 I negative spindle sense ampliﬁer input SISENS 15 O spindle sense ampliﬁer output AGND 16 − general analog ground; note 1 I

ref

SINTIN 18 I negative integrator input ISPIN 19 I positive integrator input, average current adjustment SICOMP 20 O integrator output RPOS 21 I duty cycle modulator input CSS1 22 I/O soft switching capacitor 1 CSS2 23 I/O soft switching capacitor 2 STOSC 24 I/O sawtooth oscillator capacitor SCANOUT 25 O test output POR

DELAY

DDA1

POR5

ADJ

POR12

ADJ

AMPIN− 30 I negative input of the uncommitted operational ampliﬁer AMPIN+ 31 I positive input of the uncommitted operational ampliﬁer PGND1 32 − power ground 1 for VCM DMOS; note 1 AMPOUT 33 O uncommitted operational ampliﬁer output RESETP 34 O power-on reset digital output with passive pull-up resistor RESETA 35 O power-on reset digital output with active pull-up resistor V

CM−

TEMPMON 37 O temperature monitor output CLAMP 38 I/O clamp capacitor used for head retraction V

DDV

CMIN2

17 O reference current generator output

26 I/O power-on reset delay capacitor (active LOW) 27 − analog supply voltage 1 (+5 V) 28 O adjustment of POR threshold (for +5 V) 29 O adjustment of POR threshold (for +12 V)

36 O negative output voltage of the VCM power stage

39 − power supply for VCM DMOS driver (+12 V) 40 I switchable VCM control input voltage

TDA5149G

1996 May 06 5

Philips Semiconductors Product speciﬁcation

12 V Voice Coil Motor (VCM) driver and spindle motor pre-driver combination chip

SYMBOL PIN I/O DESCRIPTION

CMIN1

CMSENSEH

CMSENSEL

CM+

H0 45 O gate control of the isolating power FET VCM

ref

BRAKEPOWER 47 I/O reservoir capacitor for the brake/park circuitry PGND2 48 − power ground 2 for VCM DMOS; note 1 V

ref(o)

CMSENSOUT

BRAKEDELAY 51 I/O powerless brake delay adjustment LATCHHOLD 52 O latch hold output LATCHACTIV 53 O latch activate output V

DDD

SCANTEST 56 I test mode input FG 57 O commutation frequency generator output CLOCK 58 I clock for digital timing input SDATA 59 I serial port data input SCLOCK 60 I serial port clock input SENABLE 61 I serial port enable input CAPX2 62 I/O charge pump capacitor input/output CAPX1 63 I/O charge pump capacitor input/output DGND 64 − digital ground; note 1

41 I VCM control input voltage 42 I positive VCM sense ampliﬁer input voltage 43 I negative VCM sense ampliﬁer input voltage 44 O positive output voltage of the VCM power stage

46 I reference voltage input for the VCM

49 O reference voltage generator output 50 O VCM sense ampliﬁer output voltage

54 − general supply voltage (+12 V) 55 − digital supply voltage (+5 V)

TDA5149G

Note

1. The 4 ground pins are tied to the lead frame for better heat dissipation.

1996 May 06 6

Philips Semiconductors Product speciﬁcation

Fig.3 Pin configuration.

handbook, full pagewidth

TDA5149G

MGE654

1 2 3 4 5 6 7 8

9 10 11 12 13 14 15 16

48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33

PGND2 BRAKEPOWER

VCM

ref H0 V

CM+

CMSENSEL

CMSENSEH

CMIN1

CMIN2

DDV

CLAMP TEMPMON V

CM−

RESETA RESETP AMPOUT

CAPY MOT0

MOT1

MOT2

MOT3

IDRIVE

SPINSENSEH

SPINSENSEL

SISENS

AGDN

DGND

CAPX1

CAPX2

SENABLE

SCLOCK

SDATA

CLOCK

SCANTEST

DDD

LATCHACTIV

LATCHHOLD

BRAKEDELAY

CMSENSOUT

ref(o)

ref

SINTIN

ISPIN

SICOMP

RPOS

CSS1

CSS2

STOSC

SCANOUT

POR

DELAY

DDA1

POR5

ADJ

POR12

ADJ

AMPIN−

AMPIN+

PGND1

12 V Voice Coil Motor (VCM) driver and spindle motor pre-driver combination chip

TDA5149G

1996 May 06 7

Philips Semiconductors Product speciﬁcation

12 V Voice Coil Motor (VCM) driver and spindle motor pre-driver combination chip

FUNCTIONAL DESCRIPTION Spindle

The spindle section contains both the low and high side pre-drivers for a three phase DC brushless motor. The digital commutation control, using the timing information provided via the serial port, is responsible for the proper switch-on and switch-off of the external power FETs. It is also responsible for selecting the correct BEMF comparator.

For optimum power efficiency, a continuous PWM method is used to control the average current from the power supply to the motor coils. This PWM mode, by controlling the average power supply current, produces a lower torque ripple and thus lower audible noise. In order to reduce further acoustic noise the TDA5149G is provided with a soft switching circuit to turn-on and turn-off linearly the switching current under PWM control. The switching transition time is controlled by the digital commutation circuit and is fixed to 50% of the time between two zero-crossings, i.e. 30° of the electrical revolution.

Soft switching is achieved by activating, during commutation, a free-running duty-cycle modulator controlled by a linearly decreasing voltage across a capacitor. This will reduce the current smoothly in the off-going leg to zero. In conjunction with this additional PWM open loop, the average current control regulates the sum of the current in the off-going and on-going leg.

This method requires two PWM control loops; one to control the average current (main loop) and one to control the current in the off-going leg. The swapping of the two loops is realized with a pair of analog switches that are sequentially switched by the digital commutation circuitry.

The PWM control also causes PWM pulses on the back EMF. These pulses disturb correct sensing of the back EMF for the zero-crossing detection. Consequently, edge-triggered latches are inserted behind the back EMF comparators, thus ensuring reliable back EMF sensing.

In the SPINMODE, programmable via the serial bus, the user can feed their own commutation pulses to the pre-drivers and control the motor in the stepper-motor mode. The commutation pulses are applied to the TDA5149G via the serial bus by setting the COMMCLK bit successively to logic 1 and logic 0.

TDA5149G

The different control modes of the TDA5149G can be commanded via the serial bus. These modes are as follows:

• Sleep mode: all analog circuits, except the power supply monitor, are switched off to reduce the power consumption of both the 12 and 5 V supplies.

• Disable mode: the output voltage of all pre-drivers is LOW thus the external power MOSFETs are not conducting.

• Brake mode: all low side pre-drivers are turned on (output voltage HIGH) thus switching on the low-side power MOSFETs. In this way the back EMF voltage of the motor is short-circuited to ground.

Voice coil motor

The VCM is a linear, symmetrical, class AB, H-bridge type power amplifier with all power devices on-chip. The driver is a transconductance amplifier that controls the output currents up to 1.65 A. The driver is constructed in a master-slave configuration with the zero current level internally adjusted in such a way that it corresponds to the middle of the output swing. Moreover, the gain of the slave has been made greater than 1 in order to ensure full saturation of the driver output VCM+.

The gain of the closed loop is programmable, using the V

GAINSEL

bus. A sense resistor (Rs) allows the measurement of the VCM current. The voltage across this resistor is connected to an accurate sense amplifier with a typical gain of 5. The output of the sense amplifier (V to the input of the VCM amplifier. Because of the symmetry of the circuit, the compensation network can be connected between the VCM1 input and the VCM− output.

Control modes such as VCM-BRAKE, VCM-DISABLE and VCM-PARK can be controlled via the serial bus.

Latch drivers

The TDA5149G provides the possibility of driving an external latch to secure the VCM heads. There are two modes; the activate mode (LACTIVE) and the hold mode (LHOLD). The hold mode is used to preserve power. Both modes are controlled via the serial bus. The drivers are switched off during the SLEEP mode or in the event of a power-down.

bit. This bit can be programmed via the serial

CMSENSOUT

) is fed back

1996 May 06 8

Philips Semiconductors Product speciﬁcation

12 V Voice Coil Motor (VCM) driver and spindle motor pre-driver combination chip

Power-on/power-off reset

The power-on reset circuitry monitors the analog, digital and general supplies. The voltage thresholds have been set internally for both supplies, i.e. 4.4 V for V V

, and 10.5 V for VDD. External adjustment and

DDD

filtering, to suppress supply spikes, has been made possible through the pins POR5

and POR12

ADJ

When either of the supplies falls below their threshold levels, the reset circuit provides two active LOW output signals. The RESETA signal is a full CMOS output and the RESETP signal has an active pull-down MOS transistor with a passive pull-up resistance of 10 kΩ. The latter can be used for emulation purposes. Both signals remain LOW until the supply voltages are again above the threshold level, delayed by a time constant period that is determined by the value of the capacitor connected to pin POR

A park sequence is initiated on a reset fault. This includes disabling the actuator latch drivers and starting a delayed spindle brake operation by switching on the low side pre-drivers simultaneously. This brake delay is determined by an external RC combination connected to BRAKEDELAY. Actuator PARK and spindle BRAKE can also be controlled via the serial port.

At power-up, the two reset output signals (RESETA and RESETP) will remain LOW as long as either supply voltage is below the specified threshold plus the hysteresis voltage. Once the supply voltages are above their specific trip levels, the two reset signals become HIGH after the power-on reset delay (POR

). This delay time is

DELAY

determined by the value of the capacitor connected to the POR

DELAY

pin.

DDA

ADJ

and

DELAY

TDA5149G

To ensure that the stored energy in the clamp capacitor is only used for the park operation, the CLAMP input must be isolated from the power supply. This can be achieved by using a Schottky diode or a reverse connected N-channel power FET (see Fig.1). The TDA5149G provides an output H0 to control this power FET.

At power-down the brake delay circuit is also enabled. The brake delay circuit is supplied by the energy stored in the capacitor (charged during normal operation from VDD) that is connected to the BRAKEPOWER pin. Both the BRAKEDELAY and BRAKEPOWER pins are then isolated from the 12 V supply voltage. When the voltage on the BRAKEDELAY pin reaches a value of 1.6 V (typ.), the low-side external power FETs are turned on to brake the spindle motor. The BRAKEPOWER capacitor then supplies the current to keep the power FETs conducting. This means that the voltage on this capacitor decreases with time.

Serial port

The serial port is used to modify the various operational modes of the TDA5149G and to adjust the timing parameters to ensure the proper commutation sequence of the spindle motor. It is a synchronous, slave only, three-wire communication port with data (SDATA), clock (SCLOCK) and enable (SENABLE) inputs.

The serial port requires the data to be sent in bytes, the LSB (data 0) to be sent first and the MSB (address 2) last. The three most significant bits (MSBs) determine the register address, the remaining five bits represent the data, which means up to 8 registers can be independently addressed.

Powerless park/brake

As with the normal retract procedure, an actuator park sequence is initiated whenever a power-down situation occurs. The power-on/power-off reset circuit generates the two active LOW reset signals and also activates the VCM park circuit. The VCM park circuit provides a voltage, retrieved from the rectified back EMF voltage of the running-out spindle, of 1.2 V (typ.) to the VCM pin. The voltage at pin VCM+ is 0 V. This voltage is supplied by the capacitor C

that is connected to the CLAMP pin.

CLAMP

This capacitor smooths the rectified back EMF and stores the electrical energy generated by the motor.

1996 May 06 9

When SENABLE is LOW, the serial port is disabled and the IC is not affected by any change both on SDATA and SCLOCK. When SENABLE is HIGH the data is written serially to the shift register on the rising edge of SCLOCK. When SENABLE goes LOW the shifting sequence is stopped and the last 8 bits that are clocked in are latched into the appropriate control register. Therefore, the transmission of two consecutive bytes requires that SENABLE is LOW for at least a duration of ‘t’ (see Chapter “Characteristics”).

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