4-channel BTL driver for CD players
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4-channel BTL driver for CD players
The BA6793FP is a 4-channel BTL driver for CD player actuators and motors. This IC has an internal 5V regulator and
a standard operational amplifier, making it suitable for a wide spectrum of applications.
CD players, CD-ROM drives
1) 28-pin HSOP power package allows for application
2) Minimum attached components.
3) Driver gain is adjustable with a single attached resistor.
Absolute maximum ratings (Ta = 25C)
Recommended operating conditions (Ta = 25C)
4) Internal 5V regulator. (requires attached PNP transistor)
5) Internal standard operational amplifier.
6) Internal thermal shutdown circuit.
7) Three separate power supplies.
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Block diagram
Pin descriptions
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Pin equivalent circuit diagrams
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Electrical characteristics (unless otherwise noted, Ta = 25C, VCC = 12V, BIAS = 2.5V, f = 1kHz, RIN = 20kΩ,
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Measurement circuit
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Circuit operation
(1) Driver
Inputs to the IC are the focus tracking error signal from
the servo preamplifier and the control signal from the motor. The input signals, which normally center on 2.5V, are
V / I converted by the preamplifier, generating a current
corresponding to the input voltage. This current is
(2) Regulator
This is a typical series regulator that generates a reference voltage internally. A PNP low saturation transistor
must be connected.
(3) Operational amplifier
A standard 4558 type.
passed through a resistor and into the internal reference
voltage component, the preamplifier output being a signal centering on the internal reference voltage. Two systems (positive phase and negative phase) are created
during V / I conversion, generating BTL output via the
driver buffer.
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Application example
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Operation notes
(1) The BA6793FP has a thermal shutdown circuit.
The output current is muted when the chip temperature
rises above 175C (typically). When the chip temperature falls to 150C (typically), the driver circuit starts up
(2) The output currents (channels 3 and 4) can be
muted by pulling up the mute pins (pins 24 and 26) above
2.0V. During ordinary use, pins 24 and 26 should be left
open or lowered below 0.5V.
(3) Muting also occurs when the bias pin (pin 22) drops
below 1.4V (typically). Make sure it stays above 2.0V during normal use.
Electrical characteristic curves
(4) Muting occurs during thermal shutdown, mute-on
operations or a drop in the bias pin voltage. In each case,
only the drivers are muted. During muting, the output pins
remain at the internal bias voltage, roughly (VCCVF) / 2.
(5) Connect the IC to a 1µF bypass capacitor between
power supplies, at the base of the IC.
(6) The radiating fin is connected to the package’s internal GND, but should also be connected to an external
(7) The capacitor between regulator output (pin 2) and
GND also serves to prevent oscillation of the IC, so select
one with good temperature characteristics.
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External dimensions (Units: mm)
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