Digital Volume Control Circuit using MAX5486

A channel digital volume circuit on IC MAX5486 is shown here. MAX5486 40K digital volume / balance controller that pushbutton interface. The IC bias voltage that eliminated of an external circuitry for purpose and thereby by reduces external count. The IC has an LED indicator driver circuit be used for driving the indicator LEDs indicates level and balance level. The IC operated from or power and in pin TSSOP package. circuit on MAX5486 applied applications like personal audio systems, audio devices, home theatre systems, audio systems, audio systems etc.

The right channel input is applied to the pin8 (high terminal (HR) of internal digital potentiometer of the IC) and left channel input is applied to the pin17 (high terminal (HL) of the second internal digital potentiometer of the IC). Low terminals (pin and 6) of potentiometers are shorted and connected to the mid bias voltage output (pin11) of the IC. at the buffered wiper terminal (pin10) of internal potentiometer and left channel output at the buffered wiper terminal of the second internal potentiometer of the IC. A 1uF capacitor is connected from the bias generator bypass (pin12) to ground. of this capacitor is noise bypassing. of capacitors C4 and C5 are to bypass noise from the VDD and VLOGIC sources. This improves stability and performance of the circuit.

LEDs D1 to D5 are the indicator LEDs indicates volume and balance levels. R1 to R5 limits current through the corresponding LEDs. 1M resistor R6 for activating the indicator LED drivers. LED D6 represents operation mode of IC. When it glows, the IC is in balance mode and when off, the IC in volume mode. Resistor R7 limits through LED D6. volume mode the LEDs work a bar graph indicating volume. balance mode, the centremost LED alone glows when a centred balance. mute mode, all indicator LEDs OFF.

Push button switches S1 to S4 are used for controlling the circuit. Pressing S1 push the IC into mute mode. Push button S4 used between volume mode and balance mode and LED D6 indicated it. Push button S2 and S3 are used for increasing and decreasing volume mode and shifting the balance to left and right balance mode. The Vss pin of the IC is grounded single operation circuit. Shutdown pin (pin6) is tied to the VLOGIC for disabling the shutdown . Connecting the shutdown pin to drive the IC to the shutdown mode.

The output of the MAX5486 is sufficient enough to drive high impedance headphones. For driving low impedance headphones or speakers an amplifier stage be added to the output. power dissipation of MAX5486 is 675mW and consider this point while selecting the loads.

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Digital High Low Logic Tester Circuit diagram

1. 
   When the input signal is logic 1, the display shows H’ and the loudspeaker emits a note which is an octave higher than the low’ tone. Operation of the circuit can be seen from the circuit diagram in figure 1 and the truth table in figure 2. When the input signal is 1, transistor T1 conducts taking the input of gate N2 above the trigger threshold and the trigger output goes to logic 0.
2. This is not our first high and low tester, but the present circuit offers something new: a seven-segment display which shows ’H or ’L’ and at the same time a small loudspeaker emits a corresponding tone.
3. lf required, the loudspeaker can be switched on by means of S1. The switch can, of course, be omitted if the audio tone is always required. lf you have an ear for music, R10 and R12 may be replaced by a 220 Q resistor and a 2509 preset potentiometer so that the tone can be adjusted to your particular liking.!
4. And all that at very reasonable cost.
5. When the supply is switched on, the decimal point of the display lights and indicates that the unit is ready For use. lf this is not the case, or an undefined signal is applied to the input, the display, apart from the decimal point, remains dark and the loudspeaker remains silent. lf the input signal is logic O, the display shows ’L’ and the loudspeaker emits a low note.
6. When the input signal is logic 0, T1 is cut off and T2 conducts. The voltage at the inputs of gates N1 and N2 are below the trigger threshold and both outputs are logic 1, switching on transistors T3 and T4; the emitter voltage of T4 rises and cuts off diodes D4 and D5. This causes a current to flow through segments d, e and f, diodes D2 and D3, resistor R6 and transistor T3.
7. With non-defined inputs (between 0.8.. . 2.15 V) and an open circuit input, both input transistors are cut off, The output of N1 is then logic 0 and that of N2 is logic 1: no current can therefore flow through any of the segments. As regards the drive for the two oscillators, suffice it to say that during low inputs N3 is driven by the output of N1 and during high in- puts N4 is driven directly by T1.
8. Transistor T2 (PNP!) is cut off, the input of gate N1 is also above the trigger threshold and this trigger output is therefore also logic 0. Both switching transistors T3 and T4 are off and a current flows through the corresponding segments (b, c, e, f, g), diodes D4 and D5 and R7. 

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Digital key with just one button Wiring diagram Schematic

This is a digital key that only uses one button to do on and off. The load is powered by the MOSFET IRFZ44 using an output of IC 4093. Only one button allows you to change the on-off state of the electronic diagram.

 Digital key with just one button Circuit Diagram

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