Ordering number: EN*5825
Monolithic Digital IC
LB8118M
Actuator Driver for Portable CD Players
Preliminary
Overview
The LB8118M is an actuator driver IC designed for portable
CD players that operate at 2.4 V (two Ni-Cd batteries) or 3.0 V
(two dry cells). Because the four-channel driver control outputs
are divided into two groups, this device reduces power
dissipation considerably during double-speed play.
Package Dimensions
unit : mm
3148-QFP44MA
[LB8118M]
Functions and Features
SANYO : QIP44MA
.
H bridge drivers (output dynamic range maximum is about 2 V) on chip for four channels to drive each CD actuator (the focus
tracking coil,
motor, and the sled motor).
.
coil, the circuit (voltagethe spindleby an external resistor) on chip that is used to apply voltage to the CD DSP, ASP and
Step-up
to be set
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microcontroller. Center-tap coil for step-up circuit makes it possible to supply the driver control voltage. (However, the drive Tr,
L, C, and Di are all external.)
Oscillator circuits for each converter on chip. (C is external.)
Four-channel driver control output is divided into two groups (the focus/tracking group and the spindle/sled group) for minimum
loss at double-speed playback. Highest operating voltage detected in each group is supplied for each 2ch H bridge driver after
PMW conversion. The single channel PWM drive without dividing the outputs into two groups is also possible. (However, the
PWM PNP-Tr, NPN-Tr, L, C, and Di are all external.)
The dynamic range of 4-channel H bridge driver output voltage is up to 2 V on the focus and tracking side, and can be set by
the Vosat pin on the spindle and sled side. However, if the 4-channel H bridge voltages in the H bridge driver block are the
same, the maximum voltage is determined using the Voset pin.
Sled motor driving mode is switchable between step drive mode for lower power dissipation, and normal V-type drive mode.
(The other three channels are fixed to V-type.)
In the spindle motor drive circuit, the control gain can be set higher for double-speed playback.
PWM step-down circuit for external power operates when external power (4 V or higher) is supplied.
In this function, external power is converted to V
CC
power supply, and two type voltage setting is possible.
In playback mode, step-up voltage for DSP has to be set equal to or lower than V
CC
, but in charging the battery, it has to be set
higher enough than V
CC
.
So step-down voltage (V
CC
) setting of two types is possible with two pairs of external resistor. (Switching port is provided.)
(However, the PWM PNP-Tr, NPN-Tr, L, C, and Di are all external.)
APC step-up power supply for the laser diode. (Also supports a pre-power supply for the internal bias.) The laser diode is
controlled with a voltage of roughly 0.5 V.
Battery pulse charging function on chip. (However, the drive NPN-Tr, and the current feedback C and R are external.)
Battery check comparator on chip.
The system can be started up and stopped by outputs from the microcontroller.
Actuator muting function on chip (for all four channels simultaneously).
Thermal shutdown circuit on chip.
SANYO Electric Co.,Ltd. Semiconductor Bussiness Headquarters
TOKYO OFFICE Tokyo Bldg., 1-10, 1 Chome, Ueno, Taito-ku, TOKYO, 110 JAPAN
D3097HA (II) No.5825-1/11
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