Mc44608; Msp34X0G - Sharp 21LF-90N Service Manual

MC44608

General description
The MC44608 is a high performance voltage-mode controller designed for off–line converters. This high voltage circuit
that integrates the start–up current source and the oscillator capacitor, requires few external components while offering
a high flexibility and reliability.
The device also features a very high efficiency stand–by management consisting of an effective Pulsed Mode operation.
This technique enables the reduction of the stand–by power consumption to approximately 1 W while delivering 300
mW in a 150 W SMPS.
• Integrated start–up current source
• Loss less off–line start–up
• Direct off–line operation
• Fast start–up
General Features
• Flexibility
• Duty cycle control
• On chip oscillator switching frequency 40, or 75 KHz
• Secondary control with few external components
Protections
• Maximum duty cycle limitation
• Cycle by cycle current limitation
• Demagnetization (Zero current detection) protection
• "Over V CC protection" against open loop
• Programmable low inertia over voltage protection against open loop
• Internal thermal protection
GreenLine Controller
• Pulsed mode techniques for a very high efficiency low power mode
• Lossless start-up
• Low dV/dT for low EMI radiation
Pinning, Pin Value
1. Demagnetization Zero cross detection voltage: 50 mV typ.
2. I Sense Over current protection voltage 1 V typ.
3. Control Input Min: 7.5 V Max.: 18 V
4. Ground Iout 2 Ap-p during scan 1.2 Ap-p during flyback
5. Driver Output resistor 8.5 Ohm sink 15 Ohm source typ.
6. Supply voltage Max: 16 V (Operating range 6.6 V - 13 V)
7. No connection
8. Line Voltage Min: 50 V Max: 500 V

MSP34X0G

The MSP 34x0G family of single-chip Multistandard Sound Processors covers the sound processing of all analog TV-
Standards worldwide, as well as the NICAM digital sound standards. The full TV sound processing, starting with analog
sound IF signal-in, down to processed analog AF-out, is performed on a single chip. Figure 3 shows a simplified
functional block diagram of the MSP 34x0G. This new generation of TV sound processing ICs now includes versions for
processing the multichannel television sound (MTS) signal conforming to the standard recommended by the Broadcast
Television Systems Committee (BTSC). The DBX noise reduction, or alternatively, Micronas Noise Reduction (MNR) is
performed alignment free.
Other processed standards are the Japanese FM-FM multiplex standard (EIA-J) and the FM Stereo Radio standard.
Current ICs have to perform adjustment procedures in order to achieve good stereo separation for BTSC and EIA-J.
The MSP 34x0G has optimum stereo performance without any adjustments. All MSP 34xxG versions are pin compatible
to the MSP 34xxD. Only minor modifications are necessary to adapt a MSP 34xxD controlling software to the MSP
34xxG. The MSP 34x0G further simplifies controlling software.
Standard selection requires a single I2C transmission only. The MSP 34x0G has built-in automatic functions: The IC is
able to detect the actual sound standard automatically (Automatic Standard Detection).
19
AK - 44
CHASSIS