LB8118M Datasheet, PDF (1/11 Pages) Sanyo Semicon Device – Actuator Driver for Portable CD Players

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}
. coil, the tracking coil, the spindle motor, and the sled motor).
Step-up circuit (voltage to be set by an external resistor) on chip that is used to apply voltage to the CD DSP, ASP and
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.}
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