150W Car Power Amplifier Circuit
When the amplifier is installed abaft in the suitcase, we shall charge a about-face works stop. The LA47536 possesses a action angle by in it pin4. This ache crave a baby astriction above to 2V in alpha up the amplifier. Transistor Q1 and Q2 makes the action of walking stop for distance. Back the disciplinarian activates the larboard indicator, either ablaze the aback fires or columnist on the anchor , lamps rear burn active Q2 who he alike fabricated to drive Q1 who applies a astriction > 2V on it pin4. Overview
LA47536 Four-Channel 45 W BTL Car Audio Ability Amplifier
The LA47536 is a 4-channel BTL ability amplifier IC developed for use in car audio systems. The achievement date features
- A authentic adulatory anatomy that uses V-PNP transistors on the aerial ancillary and NPN transistors on the low ancillary to accommodate aerial ability and superb audio quality.
- The LA47536 includes about all the functions appropriate for car audio use, including a standby switch, a muting function, and anniversary aegis circuit. It additionally provides a self-diagnosis action (output account detection). (Sanyo)
Functional Description
1. Standby About-face Action (pin 4)
The pin 4 beginning voltage is set to be 2 VBE. Back Vst is 2.0V or higher, the amplifier will be on, and back Vst, is 0.7V or lower, the amplifier will be off. Note that pin 4 requires an operating accepted of at atomic 40uA.
2. Muting Function
The IC is set to the aerial accompaniment by ambience pin 22 to the arena potential. In this state, the audio achievement is muted. The time connected with which the muting action operates is set by an alien RC circuit, and this time connected influences the pop babble that occurs back the amplifier is angry on or off.
The muting on and off times due to the recommended alien basic ethics (R=10k, C=3.3uF) are as follows.
Muting on time: 50ms
Muting off time: 20ms
3. Self-Diagnosis Action (Speaker addict prevention)
During abiding accompaniment operation, the LA47536 detects, internally, whether or not an aberrant amplifier achievement account has occurred, and outputs this arresting from pin 25. Applications can anticipate apostle addict and added problems by accepting the arrangement microcontroller ascertain this pin 25 achievement arresting and ascendancy either the standby accompaniment or the ability supply. (An aberrant achievement account may be acquired by, for example, ascribe capacitor arising current.) The pin 25 arresting is angry off by ambience pin 1 to the arena potential.
4. Oscillator Stability
In some cases, abject oscillations may be induced by the PCB layout. This cadence can be alone by abacus the apparatus listed below. Note that the optimal capacitor amount charge be absolute by testing in the absolute army accompaniment in the end product. Connect a capacitor and resistor (0.1uF and 2.2) in alternation amid anniversary achievement pin and ground.
5. Audio Affection (Low band)
The abundance characteristics in the low frequencies can be bigger by authoritative the capacitance of the ascribe capacitors variable. The recommended capacitance is 2.2uF and smaller.
6. Aegis Circuits
Do not arena the outputs with the STBY voltage at about 1.4V. Also, do not about-face the IC off in the ashore accompaniment with a time connected provided for the STBY voltage.
7. Pop Noise
Although the LA47536 includes an pop babble blockage circuit, pop babble can be bargain alike added by application the muting action as well. Activate the muting action at the aforementioned time as ability is applied. Then, afterwards the achievement DC abeyant has stabilized, about-face off the muting function. Back axis the amplifier off, aboriginal about-face on the muting action and again about-face off the ability supply. These two methods are able at aspersing pop noise.
