Hitachi 32LD8600, Руководство по обслуживанию

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27
TFT TV Service Manual
11.26. LM2576
11.26.1. General Description
The LM2576 series of regulators are monolithic integrated circuits ideally suited for easy and
convenient design of a step–down switching regulator (buck converter). All circuits of this series are
capable of driving a 3.0 A load with excellent line and load regulation.
These devices are available in fixed output voltages of 3.3 V, 5.0 V, 12 V, 15 V, and an adjustable
output version. These regulators were designed to minimize the number of external components to
simplify the power supply design. Standard series of inductors optimized for use with the LM2576 are
offered by several different inductor manufacturers.
Since the LM2576 converter is a switch–mode power supply, its efficiency is significantly higher in
comparison with popular three–terminal linear regulators, especially with higher input voltages. In many
cases, the power dissipated is so low that no heatsink is required or its size could be reduced
dramatically.
A standard series of inductors optimized for use with the LM2576 are available from several different
manufacturers. This feature greatly simplifies the design of switch–mode power supplies.
The LM2576 features include a guaranteed ±4% tolerance on output voltage within specified input
voltages and output load conditions, and ±10% on the oscillator frequency (±2% over 0°C to 125°C).
External shutdown is included, featuring 80 mA (typical) standby current. The output switch includes
cycle–by–cycle current limiting, as well as thermal shutdown for full protection under fault conditions.
11.26.2. Features
• 3.3 V, 5.0 V, 12 V, 15 V, and Adjustable Output Versions
• Adjustable Version Output Voltage Range, 1.23 to 37 V ±4% Maximum Over Line and Load
Conditions
• Guaranteed 3.0 A Output Current
• Wide Input Voltage Range
• Requires Only 4 External Components
• 52 kHz Fixed Frequency Internal Oscillator
• TTL Shutdown Capability, Low Power Standby Mode
• High Efficiency
• Uses Readily Available Standard Inductors
• Thermal Shutdown and Current Limit Protection
• Moisture Sensitivity Level (MSL) Equals 1
11.26.3. Pin description
11.27. TDA1308
11.27.1. General Description
The TDA1308 is an integrated class AB stereo headphone driver contained in an SO8 or a DIP8 plastic
package. The device is fabricated in a 1 mm CMOS process and has been primarily developed for
portable digital audio applications.
11.27.2. Features
• Wide temperature range
• No switch ON/OFF clicks
• Excellent power supply ripple rejection
• Low power consumption