Advertisement

Article

BTL power amp and multi voltage regulator support car radio apps

The TDA8587J from Philips Semiconductor is a combination of a quad Bridge-Tied Load (BTL) power amplifier, a multiple voltage regulator and a power switch. Several protections and diagnostic options, including. DIAG, WARN, are incorporated in this design.

schematic

The TDA8587J supports the complete power supply and audio amplifier requirements in low and mid-end car radio applications. The switchable regulators (regulators 1, 3 and 4) are intended to be used as supplies for the tuner, logic, digital or analog sound processor and CD / tape control.

The standby regulator (regulator 2) is specially designed as a supply for a microcontroller. In combination with the reset delay capacitor (pin RDC) and the reset output (pin RST), a proper start-up sequence for the microcontroller is guaranteed. The storage capacitor (pin STC) makes this regulator output insensitive for short battery drops (e.g. engine start).

The power switch (pin PSW) can be used for switching an electrically powered antenna, display unit or CD / tape driver. The smart combination of two dynamic buffers and four amplifier output stages makes it possible to create a full quad BTL amplifier, using only six output pins.

General features
* Protected against ElectroStatic Discharge (ESD)
* Thermal (foldback) protection to prevent overheating
* Load dump/overvoltage protection
* Single mode control pin (standby, operating: mute/on)
* Low standby current (only regulator 2 active)
* Hysteresis on internal switching levels
* Low power dissipation in any short-circuit condition
* Package with flexible leads (easy manual assembly)
* DBS27 package with low thermal resistance

Regulator features:
* Three mode pin controlled regulators i.e. regulator 1 = 8.5 V, regulator 3 = 5.0 V and regulator 4 = 3.3 V
* One mode pin controlled power switch
* One standby regulator i.e. regulator 2: 5.0 V (e.g. supply for a microcontroller)
* A storage capacitor is present as back-up supply for regulator 2 in case of loss of battery
* All regulator and power switch outputs are short-circuit proof to ground and to the supply lines (current foldback)
* In the event of an internal or external fault condition a warning output can be used to trigger a microcontroller
* A reset output can be used to 'call' a microcontroller in a smooth way (adjustable delay) at the first power-up

Amplifier part
* Four 25 W BTL power amplifiers, realized in a unique six pin output configuration
* Internally fixed gain (26 dB)
* No switch-on / switch-off plops when switching between standby and mute and between mute and operating
* All amplifier outputs are short-circuit proof to ground, supply lines and across the speakers (soft + hard detection)
* A low supply mute function is implemented to obtain a fast mute at supply voltage drops (e.g. engine start)
* A diagnostic output gives clip information (THD = 10 pct.), indicates a short-circuit at an amplifier output and gives a thermal foldback pre-warning

TDA8587J data sheet

0 comments on “BTL power amp and multi voltage regulator support car radio apps

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.