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Ordering number : EN4946A
Monolithic Digital IC
LB8108M
Actuator Driver for Portable CD Players
Applications
The LB8108M is an actuator driver for use in portable CD players that operate at a power supply voltage of 2.4 (two nicad batteries) or 3.0 V (two dry-cell batteries).
Functions and Features
* Includes four H bridge driver channels to drive the four CD player actuators (focus coil, tracking coil, spindle motor and sled motor). (output dynamic range: maximum of about 2 V) * Includes a 3.9 V (typical) step-up circuit to supply the DSP, ASP and microprocessor used in the CD player. Also includes another voltage step-up circuit whose voltage can be set with external resistors. (However, note that the transistors, inductors, capacitors and diodes required for drive operation are all external components.) * Built-in oscillator circuit for these converters (external resistor and capacitor required) * Detects the maximum value of the four driver outputs and supplies a voltage slightly higher than that voltage to the H bridge block in each of the four channels using PWM voltage converter. This allows a drive scheme with extremely low loss to be implemented. (However, note that the pnp transistor, inductor, capacitor, and diodes for the PWM circuit are all external components.) * Built-in laser diode drive and APC circuits (IOmax 100 mA. This function can be turned off by a control voltage input. It is composed of step-up converter and series regulator. However, note that the transistors, inductors, capacitors and diodes required for drive operation are all external components.) * The sled motor drive circuit operates in 2 modes, that are normal V-type drive mode and step drive mode which is highly effective in reducing power dissipation.
* A step-down converter that convert external input voltage that exceed 5 V into 3.5 V VCC operates when an external voltage input is applied. This simplifies power supply design and thermal design for applying VCC. (This circuit turns on at the same time an external voltage is applied and generates a 3.5 V VCC, which is utilize for nicad battery charging.) * Built-in microprocessor reset circuit (external capacitor required) (This circuit detects the VCD pin voltage and operates a reset voltage with an H-side of 2.2 V (typical) and an Lside of 2.1 V (typical).) * Two built-in battery check comparator channels * System start and stop under microprocessor control * Actuator muting function included. (all four channels at the same time) * Built-in thermal shutdown circuit
Package Dimension
unit: mm 3148-QFP44MA
[LB8108M]
SANYO: QIP44MA
SANYO Electric Co.,Ltd. Semiconductor Bussiness Headquarters
TOKYO OFFICE Tokyo Bldg., 1-10, 1 Chome, Ueno, Taito-ku, TOKYO, 110-8534 JAPAN
73196RM/51795TH (OT) No. 4946-1/12
LB8108M
Specifications
Absolute Maximum Ratings at Ta = 25C
Parameter Maximum supply voltage External input voltage H bridge output current Step-up circuit output current Allowable power dissipation Operating temperature Storage temperature Symbol VCC max VEXT max IOUT max ICD max Pd max Topg Tstg Independent IC Taking 400 mA per channel as the maximum. Conditions Ratings 7 9 800 150 900 -20 to +75 -55 to +150 Unit V V mA mA mW C C
Allowable Operating Ranges at Ta = 25C
Parameter Supply voltage External input voltage Symbol VCC VEXT Conditions Ratings 1.6 to 3.5 5.0 to 8.0 Unit V V
Electrical Characteristics at Ta = 25C, VCC = 3 V
Parameter [Power Supply Block] Standby current drain Quiescent current [Step-up Circuit (3.9 V)] Step-up output voltage NPN drive current Load regulation Line regulation Minimum off duty [Externally Set Step-Up Circuit] NPN drive current Input bias current Minimum off duty [H Bridge Output Block, PWM Block] Output saturation voltage Maximum output voltage PNP drive current Load regulation Line regulation [Drive Control Block] Input bias current ASP reference input voltage range Transfer gain Transfer gain difference (+/-) Input dead zone voltage [Sled Drive Circuit] SLREF input voltage range Input bias current SLM on voltage [Oscillator Block] Oscillator power output voltage Oscillator maximum frequency OSC pin input bias current VOSCP FMAX IB OSC -2.0 VCC - 0.15 100 V kHz A VSLREF IB SLED VSLM 2.0 VCD - 0.5 200 V nA V IB IN VASPR GIN GIN VDZ For RL = 10 For RL = 10 -1.0 -30 1.2 7.95 0 0 +1.0 +30 2.0 VCD - 1.3 A V dB dB mV VH sat VPWM max ID PWM RLD PWM RLN PWM IO = 200 mA, TOP + BOTTOM 0.30 2.25 VOUT/600 1000 100 0.45 V V mA mV/A mV/V ID UP IB UP DMIN UP 50 3.0 200 mA nA % VCD ID CD RLD CD RLN CD DMIN CD 50 3.7 3.9 3.0 1000 100 4.1 V mA mV/A mV/V % ICCO ICC S/S = high S/S = low, with no drive input 16 100 25 A mA Symbol Conditions min typ max Unit
Continued on next page. No. 4946-2/12
LB8108M
Continued from preceding page.
Parameter [Battery Check Block] BI1 and BI2 input bias current BO1 and BO2 output saturation voltage [S/S Pin Function] S/S start voltage S/S off voltage [External Voltage Input Block] Minimum operating input voltage PNP drive current Step-down circuit output voltage [Muting Block] Muting on voltage [APC Circuit Block] Maximum output current LDCTL pin input bias current LDCTL off voltage MDin pin input bias current VLD step-up voltage NPN drive current [Reset Circuit Block] Reset charge current Output saturation voltage H side detection voltage L side detection voltage [TSD Block] TSD operating temperature TSD temperature hysteresis TTSD TTSD Design target value*2 Design target value*2 180 20 C C ICHG VRST VHSENSE VLSENSE For IO = 100 A For the VCD pin voltage*1 For the VCD pin voltage*1 2.1 2.0 2.2 2.1 -1.25 0.3 2.3 2.2 A V V V IO APC IB LDC VLDOFF IB MDIN VLDOUT ID LDO Taking VLDO as the reference -1.0 0.3 1.0 -5.0 0.4 100 mA A V A V mA VMUTE 2.0 V VI EXT ID EXT VO EXT 3.3 5.0 3.0 3.5 3.7 V mA V VSS ON VSS OFF VCC - 0.5 VCC - 1.0 V V IB BI1, 2 VBO1, 2 For IO = 500 A 200 0.3 nA V Symbol Conditions min typ max Unit
Note: 1. VHSENSE and VLSENSE will never be inverted in any individual IC. 2. Items specified to be a design target value in the conditions column are not measured.
No. 4946-3/12
LB8108M Pin Assignment
No. 4946-4/12
LB8108M Pin Functions
Pin No. Symbol Equivalent circuit Function
1, 44 33, 34 2
IN1, IN2 IN3, IN4 ASPREF
The actuator control signals corresponding to IN1: focus, IN2: tracking, IN3: spindle, IN4: sled. Input from the ASP (DSP).
Focus coil actuator drive output 43, 42 41, 40 38, 37 36, 35 OUT1+, 1- OUT2+, 2- OUT3+, 3- OUT4+, 4- Tracking coil actuator drive output Spindle motor drive output Sled motor drive output (Each channel includes built-in spark killer diodes.)
3, 31
VOUT
Power supply for the four H bridge driver channels. An external PWM step-up circuit can be used to generate a voltage slightly higher than the maximum voltage output by any of the four output channels. Input for the 3.9 V step-up circuit. The drive control system operates on this voltage. This voltage can also be supplied to other ICs in the system, such as the DSP and the microprocessor.
4
VCD
5
MUTE
Input for muting of the four actuator channels at the same time. High: mute applied.
6
SLREF
Threshold input used when operating the sled motor in step drive mode.
7
SLM
Input that selects sled motor step drive mode. High: V-type selected Low: Step mode
8
LD GND
Dedicated ground connection for the internal reference voltage for laser diode APC control. Connect to a ground near the laser diode.
Continued on next page. No. 4946-5/12
LB8108M
Continued from preceding page.
Pin No. Symbol Equivalent circuit Function
9
LDCTL
Laser diode APC (auto power control) control signal input. When this voltage falls under about 0.4 V the APC output is turned off.
10
OSCPWR
RC power supply for invalid current prevention for the OSC oscillator circuit.
28
OSC
Input for the free-running oscillator circuit used for PWM step-down and step-up circuits. The oscillator frequency is determined by an external RC circuit.
11
EXTDRV
Base drive output for external step-down pnp transistor used when external power is applied.
12
EXTVCC
External power supply input. This voltage is converted into 3.5 V with a PWM step-down circuit and supplied to VCC.
13
MD in
Input for the output from the laser diode APC monitor diode.
14
CLD
Terminal for the capacitor that eliminates high frequency from laser drive signal. This capacitor is also useful for soft starting in the LD output.
Continued on next page. No. 4946-6/12
LB8108M
Continued from preceding page.
Pin No. Symbol Equivalent circuit Function
15
VLDO
Output that directly drives the laser diode. IO max is about 100 mA.
16
VLD
Input in the laser APC circuit for the external step-up circuit used to assure VLDO (i.e., to assure VCE for the internal output transistor) when VCC falls. VLD is controlled to 0.3 V (typical) more than VLDO.
17
GND
LB8108M small signal system ground (ground for circuits without the output transistor) Base drive circuit for external step-up npn transistor in the laser APC circuit for the external step-up circuit used to assure VLDO when VCC falls.
18
LDUPB
25
DNB
Base drive output for the step-down PWM pnp transistor that generates the power supplied to the actuator H bridge drivers.
27
UPBASP
Base drive output for the external npn transistor for the step-up circuit whose stepup voltage is set externally. Base drive output for the 3.9 V step-up external npn transistor.
29
UPBCD
19
CT
Terminal for the reset circuit capacitor (The reset time will be about 50 ms for a 0.1 F capacitor.)
20
RST
Reset circuit open collector output
21, 22
BO1, BO2
Battery check comparator open collector output
24, 23
BI1, BI2
Battery check comparator input. This voltage is compared to 1.2 V internally.
Continued on next page. No. 4946-7/12
LB8108M
Continued from preceding page.
Pin No. 26 Symbol VCC Equivalent circuit Function Power supply connection
30
S/S
LB8108M start input (starts on a low level input). No power on lock function is included.
32
UPASP
Voltage feedback input for the externally set step-up circuit. The step-up voltage is determined by comparing this voltage to 1.2 V.
39
PGND
Ground for the four H bridge driver channel output transistors. This ground is not connected to the small signal system ground internally.
No. 4946-8/12
LB8108M Block Diagram
No. 4946-9/12
LB8108M Operating Description Reset Function The LB8108M includes a built-in circuit that outputs a reset signal to the control microprocessor. This circuit operates when VCC is applied. (It does not depend on the S/S circuit.) The reset time is determined by the capacitor connected to the CT pin, and will be about 50 ms for a 0.1 F capacitor. The level detection circuit detects the VCD voltage as shown in the figure.
That is, the reset state is cleared by RST going from low to high after the passage of the time determined by CT starting at the point the VCD voltage exceeds 2.2 V (typical) after VCC is applied. At this time RST will remain cleared even if S/S is turned on and VCD rises to 3.9 V (typical). Then, if S/S is turned off and the VCD voltage returns to the voltage determined by VCC and the Schottky diode voltage drop, and additionally, the VCD voltage falls under 2.1 V (typical) due to a drop in the battery voltage, reset is applied (turned on) again. (In other words, there is hysteresis in the detection level.) (Note that since the RST output has a limited drive current, it should be used with a pull-up resistor of about 100 k.) APC Function In systems that used earlier drivers, the laser diode APC (auto power control) circuit that adopted an ASP (analog signal processor) were generally used. However, this ASP was originally driven by the power supply stepped up from VCC by the driver IC and the laser diode was then driven by a series type regulator supplied by that voltage. This had the problem that the power dissipation was large. This power dissipation takes a large part of the total power dissipation in the whole system, especially in portable equipment. To reduce this power dissipation, the LB8108M takes the power for the laser diode directly from VCC. (In practice, this circuit consists of an up converter and a series regulator. When the VCC voltage is high enough, the circuit operates as a series type circuit, but since these circuits are expected to be used in portable applications, that will be relatively rare.) Laser Diode Drive Technique in General Overview of the LB8108M Laser Diode Drive System
No. 4946-10/12
LB8108M First, when VCC is adequately high (about 2.5 V or over) the laser diode is driven by the system consisting of VCC, an inductor and a Schottky diode without driving LDUPB. Then, when VCC falls and VLD - VLDO become under about 0.3 V, LDUPB is driven, VLD is stepped up, and the circuit is controlled so that VLD - VLDO is held at 0.3 V (typical). The following describes the laser diode intensity adjustment function supported by the LB8108M. First, set up the pickup so that the monitor diode output is about 0.2 V in the normal usage range. When LDCTL is in the range 0.0 to 0.5 V the LD drive function will be in the cutoff state and the laser diode will not be driven. As the LDCTL voltage rises, the LD drive reference voltage shown in the figure varies between 0.1 and 0.3 V. Then, the VLDO pin voltage is controlled so that the monitor diode output and that reference voltage become identical. However, since the output current peak is 100 mA (typical), the output voltage will not increase when an output current in excess of that value is required. (Since the intensity adjustment will go to its maximum setting when the LDCTL pin is open, an appropriate voltage must be applied to the LDCTL pin.) Sled Control The figure below shows the operation of the LB8108M's sled actuator step control. When the SLM pin is set high, the LB8108M operates in the normal V-type control mode. However, the LB8108M can be set to operate in a sled drive mode that is highly efficient at reducing power dissipation by setting the SLM pin low. The step drive start level is input from the SLREF pin. (Only a voltage higher than VASPREF will be accepted.) The circuit operates once in step drive mode following the locus of line in the figure. Then, on returning, it operates in V-type control following the locus of line . Next, the circuit can be operated in step mode by putting the input (VIN4) into the reverse region. (If the input does not enter the reverse region, the circuit will continue to operate in V-type mode.)
No. 4946-11/12
LB8108M
s No products described or contained herein are intended for use in surgical implants, life-support systems, aerospace equipment, nuclear power control systems, vehicles, disaster/crime-prevention equipment and the like, the failure of which may directly or indirectly cause injury, death or property loss. s Anyone purchasing any products described or contained herein for an above-mentioned use shall: Accept full responsibility and indemnify and defend SANYO ELECTRIC CO., LTD., its affiliates, subsidiaries and distributors and all their officers and employees, jointly and severally, against any and all claims and litigation and all damages, cost and expenses associated with such use: Not impose any responsibility for any fault or negligence which may be cited in any such claim or litigation on SANYO ELECTRIC CO., LTD., its affiliates, subsidiaries and distributors or any of their officers and employees jointly or severally. s Information (including circuit diagrams and circuit parameters) herein is for example only; it is not guaranteed for volume production. SANYO believes information herein is accurate and reliable, but no guarantees are made or implied regarding its use or any infringements of intellectual property rights or other rights of third parties. This catalog provide information as of July, 1996. Specifications and information herein are subject to change without notice. PS No. 4946-12/12

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