In this post we learn about a simple single cheap 70 watt high efficiency power amplifier circuit using the IC TDA1562
The TDA1562Q consists of a mono class-H BTL output power amplifier.
During lower output power, approximately 18 W, the system works like a typical BTL amplifier. If a much larger output voltage swing is necessary, the internal supply voltage will be elevated by using the external electrolytic capacitors. Because of this for a few seconds increased supply voltage the accessible output power becomes 70 W.
Within regular use, once the output is powered using music-like signals, the high output power is barely required throughout a modest portion of time. With the supposition that a audio signal includes a regular (Gaussian) amplitude syndication, the decrease in dissipation is approximately 50% while in comparison to a class-B output ampliﬁer using the identical output power.
The heatsink must be suitable for utilizing with audio signals. In the event the case temperature surpasses 120 C, the IC may move back through class-H to class-B functionality. The higher power supply voltage can now be impaired as well as the output power will be limited to 20 W. Once the supply voltage declines under the lowest working point, the amplifier is going to be muted right away.
Mode select input (pin MODE) This pin offers 3 settings:
1. LOW, ‘standby’: the entire circuit is turned off, the supply current is rather reduced
2. MID, ‘mute’: the circuit is started up, however the input signal will be diminished
3. HIGH, ‘on’: standard functioning, the input signal is amplified through 26 dB. Once the circuit is actually switched through mute to ON or vice versa typically the switching happens with a zero crossing of the input signal. The circuit includes a speedy start off alternative, i.e. whenever it is turned straight from standby to on, the amplifier can be completely functional within just 50 ms (vital for purposes such as car telephony and vehicle direction-finding).
Status IIO input (pin STAT) INPUT
This input offers 3 options:
1. LOW, ‘fast mute‘: the circuit continues to be switched on, however the input signal is under control
2. MID, ‘class-B’: the circuit works like class-B amplifier, the high power supply voltage is unable to function well, in addition to the case temperature
3. HIGH, ‘class-H’: the circuit functions as class-H amplifier, the high power supply voltage is actually endowed, regardless of the case temperature.
Once this 70 watt power amplifier circuit is turned up through fast mute to class-B/H or vice versa the transitioning is quickly executed. When the circuit is transferred from class-B to class-H or the other way round the particular changing happens in a zero crossing of the input signal.
OUTPUT This output offers 3 options: 1. LOW, ‘mute’: approve of muted ampliﬁer 2. MID, ‘class-B’: the circuit works as class-B amplifier, the high power supply voltage is unable to function well, due to the case temperatures TC > 120 C 3. HIGH, ‘class-H’: the circuit runs like class-H amplifier, the high power supply voltage is activated, since the case temperature TC < 120 C. Once the circuit is transferred from class-B to class-H or vice versa the particular transitioning occurs in a zero crossing of the input signal. The state I/O pins of maximum 8 ICs could be connected collectively for synchronizing functions.
Diagnostic output (pin DIAG) DYNAMIC DISTORTION DETECTOR (DDD)
On the start clipping of the output stages, the DDD gets to be effective. These details may be used to commute a sound processor chip or DC-volume control in order to attenuate the input signal and thus control the distortion.
Each time a short-circuit takes place in the output to ground or to the supply voltage, the output stages tend to be turned off. Will have them started up once again around 20 ms following removing the short-circuit. Within this short-circuit condition the diagnostic result is actually consistently REDUCED.
Whenever a short-circuit arises over the load, the output stages tend to be turned off throughout roughly 20 ms, Right after that period will be examined throughout around 50 us whether or not the short-circuit continues to be present. In this short-circuit condition the diagnostic output is REDUCED for 20 ms and also high for 50 us. The power dissipation in a short-circuit condition is incredibly reduced.
Right before the temperature security gets to be effective the diagnostic output turns into endlessly LOW.
Load detection: instantly following the circuit is turned from standby to mute or on, the built-in recognition circuit check ups if the load exists.
The outcomes of this test could be discovered in the diagnostic output, through switching the mode select input within the mute mode. Because the diagnostic output can be an open collector output, a lot more devices could be connected jointly.
Technical Specifications for the IC TDA1562
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