SA1469TN Datasheet, PDF (5/11 Pages) Silan Microelectronics Joint-stock – 4-CH BTL DRIVER FOR CD PLAYER WITH 3.3V OUTPUT VOLTAGE

2. TSD (THERMAL SHUTDOWN)
SA1469TN
1) The VREF is the output voltage of the band-gap-referenced biasing circuit and acts as the input voltage of the
TSD circuit.
2) The base-emitter voltage of the TR, Qn is designed to turn-on at below voltage.
VBE=VREF * R2/(R1+R2)=460mV
3) When the chip temperature rises up to 175°C, then the turn-on voltage of the Qn would drop down to 460mV.
(Hysteresis: 25°) and, the Qn would turn on so the output circuit will be muted.
3. OP-AMP
OP-Amp is integrated in the IC for user convenuence.
OPIN(+)
OPIN(-)
OPOUT
Pins 14, 15 and 16 may be left open when the operational amplifier is not used.
4. DRIVER
1) The voltage, VREF, is the reference voltage given by the BIAS voltage of the pin # 23.
2) The input signal through the pin # 3 is amplified by 10K/10K times and then fed to the level shift.
3) The level shift produces the current due to the difference between the input signal and the arbitrary reference
signal. The current produced as +ΔV and -ΔV is fed into the driver buffer.
4) Driver buffer operates the power TR of the output stage according to the state of the input signal.
5) The output stage is the BTL driver and the motor is rotating in forward direction by operating TR Q1 and TR
Q4. on the other hand, if TR Q2 and TR Q3 is operating, the motor is rotating in reverse direction.
6) When the input voltage through the pin # 3 is below the VREF, then the direction of the motor in forward
direction.
7) When the input voltage through the pin # 3 is above the VREF, then the direction of the motor in reverse
direction.
8) If it is desired to change the gain, then the pin # 4 or # 24 can be used.
HANGZHOU SILAN MICROELECTRONICS CO.,LTD
Http://www.silan.com.cn
REV:1.2 2008.07.23
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