Read Sharp 76FW-53H (serv.man13) Service Manual online
Colour Television – DA100/DW100 Chassis
Sharp Electronics (UK) Ltd
Technical Support
September 99
Page 7
CLASS D OUTPUT STAGES
The class ‘D’ output stages that Sharp Electronics have used since the introduction of the CS chassis
are now incorporated into a specially design integrated circuit (TDA7480 = 10w output power,
TDA7481 = 15w output power and TDA7482 = 25w output power). These devices are ideal for use
with TV Audio & Field output stages where high efficiency (low energy use) is required.
are now incorporated into a specially design integrated circuit (TDA7480 = 10w output power,
TDA7481 = 15w output power and TDA7482 = 25w output power). These devices are ideal for use
with TV Audio & Field output stages where high efficiency (low energy use) is required.
Sharp Electronics are currently using the TDA7480 for Audio and Frame outputs and the TDA7481 to
drive the sub-woofer.
drive the sub-woofer.
T
DA
7480 P
IN
F
UNCTIONS
Pin No.
Name
Function
1
2
3
4
5
6
7
8
9
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
11
12
13
14
15
16
17
18
19
20
-V
CC
-V
CC
-V
CC
OUT
BOOTDIODE
BOOT
NC
FEEDCAP
FREQUENCY
SGN-GND
IN
ST-BY-MUTE
NC
+V
BOOTDIODE
BOOT
NC
FEEDCAP
FREQUENCY
SGN-GND
IN
ST-BY-MUTE
NC
+V
CC
SIGN
VREG
+V
+V
CC
POW
-V
CC
-V
CC
-V
CC
-V
CC
NEGATIVE SUPPLY.
NEGATIVE SUPPLY.
NEGATIVE SUPPLY.
PWM OUTPUT
BOOTSTRAP DIODE ANODE
BOOTSTRAP CAPACITOR
NOT CONNECTED
FEEDBACK INTEGRATING CAPACITANCE
SETTING FREQUENCY RESISTOR
SIGNAL GROUND
INPUT
ST-BY/ MUTE CONTROL PIN
NOT CONNECTED
POSITIVE SIGNAL SUPPLY
10V INTERNAL REGULATOR
POSITIVE POWER SUPPLY
NEGATIVE SUPPLY (De-coupled by 100nF)
NEGATIVE SUPPLY
NEGATIVE SUPPLY
NEGATIVE SUPPLY
NEGATIVE SUPPLY.
NEGATIVE SUPPLY.
PWM OUTPUT
BOOTSTRAP DIODE ANODE
BOOTSTRAP CAPACITOR
NOT CONNECTED
FEEDBACK INTEGRATING CAPACITANCE
SETTING FREQUENCY RESISTOR
SIGNAL GROUND
INPUT
ST-BY/ MUTE CONTROL PIN
NOT CONNECTED
POSITIVE SIGNAL SUPPLY
10V INTERNAL REGULATOR
POSITIVE POWER SUPPLY
NEGATIVE SUPPLY (De-coupled by 100nF)
NEGATIVE SUPPLY
NEGATIVE SUPPLY
NEGATIVE SUPPLY
P
IN
9 – F
REQUENCY
The external components on this pin will determine the base frequency of the PWM section of this IC.
Remember for the audio circuit the frequency will vary from the base frequency by the bandwidth of
the audio signal (20kHz).
Remember for the audio circuit the frequency will vary from the base frequency by the bandwidth of
the audio signal (20kHz).
P
IN
12 – M
UTE
/S
TANDBY FUNCTION
The voltage at pin 12 will determine the working condition of this device. A voltage of less than 0.8v
will tell the device to switch to standby, where a voltage between 1.8v to 2.5v will result in the output
being attenuated between 60 to 80 dB. For normal operation the voltage at pin 12 should be greater
than 4v.
will tell the device to switch to standby, where a voltage between 1.8v to 2.5v will result in the output
being attenuated between 60 to 80 dB. For normal operation the voltage at pin 12 should be greater
than 4v.
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