NXP公司的TDF8551J是采用BCDMOS技術的I2C總線控制4x45W功率放大器,包含有四個BTL配置的放大器,能驅動四個揚聲器:兩個前面和兩個后面通路.每個放大器可獨立配置,線路驅動模式的增益為20dB,放大模式的增益為26dB.此外, TDF8551J還集成了6個輸出電壓穩壓器和兩個功率開關.本文介紹了TDF8551J主要特性,方框圖和測試與應用電路圖.
TDF8551J: I2C-bus controlled 4x45 W power amplifier with six voltage regulators
The TDF8551J has a complementary quad audio power amplifier that uses BCDMOS technology. It contains four amplifiers configured in Bridge-Tied Load (BTL) to drive four speakers: two front and two rear channels. The I2C-bus enables diagnostic information of each amplifier and its speaker to be read separately. Both front and both rear channel amplifiers can be configured independently in line driver mode with a gain of 20 dB (differential output) or amplifier mode with a gain of 26 dB (BTL output).
The TDF8551J has six output voltage regulators and two power switches:
• Four switchable regulators and two standby regulators
• Two power switches with loss-of-ground protection and surge protection
• Second supply pin to reduce dissipation by means of an external DC-to-DC converter
• Backup functionality for regulator 2
TDF8551J主要特性:
Amplifiers
I2C-bus control
Can drive a 2 load with a battery voltage of up to 16 V and a 4 load with a battery voltage of up to 18 V
DC load detection: open, short and present
AC load (tweeter) detection
Programmable clip detect; 1 % or 3 %
Programmable thermal protection pre-warning
Independent short-circuit protection for each channel
Selectable line driver (20 dB) and amplifier mode (26 dB)
Loss-of-ground and open VP safe
All outputs protected from short-circuit to ground, to VP or across the load
All pins protected from short-circuit to ground
Soft thermal-clipping to prevent audio holes
Low battery detection
Voltage regulators and switches
I2C-bus control
Good stability for any regulator with almost any output capacitor value
Six voltage regulators (microcontroller, display, audio processor, tuner, bus, mechanical digital and drive)
Selectable output voltages for regulators 1, 4 and 5
Low dropout voltage PNP output stages
High supply voltage ripple rejection
Low noise for all regulators
Two power switches (antenna switch and amplifier switch)
Standby regulators 2 and 6 (microcontroller and bus supply) operational during load dump and thermal shutdown
Low standby quiescent current (regulators 2 and 6 operational only)
Second supply pin for connecting optional external DC-to-DC converter to reduce internal dissipation
Backup functionality for regulator 2
Protection
If connection to the battery voltage is reversed, all regulator voltages will be zero
Withstands output voltages up to 18 V (supply line may be short-circuited)
Thermal protection to avoid thermal breakdown
Load dump protection
Regulator outputs protected from DC short-circuit to ground or to supply voltage
All regulators protected by foldback current limiting
Power switches protected from loss-of-ground and surge conditions
圖1.TDF8551J方框圖
圖2.TDF8551J測試和應用方框圖
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