Showing posts with label usb. Show all posts
Showing posts with label usb. Show all posts
Wednesday, November 19, 2014
USB SPDIF DAC with IC PCM 2902
The tool that I made and I discuss in this article I give the name USB SPDIF DACEvery word in the name corresponds to the function of the tool that I made this.
USB, this device serves to take the music information in digital form from a computer via the USB port
SPDIF, this tool can output digital music information received through the USB port, through the SPDIF output terminal that is also present in this device, so if you have a DAC that does not have a USB input, you can still use and do not need to buy a new DAC that has an input USB.
DAC, this tool can convert the digital signals derived from the USB port, an analog signal, which you can connect to the amplifier to the ahirnya you can hear the speaker
Scheme of the USB DAC can be seen in Figure 1 below.USB, this device serves to take the music information in digital form from a computer via the USB port
SPDIF, this tool can output digital music information received through the USB port, through the SPDIF output terminal that is also present in this device, so if you have a DAC that does not have a USB input, you can still use and do not need to buy a new DAC that has an input USB.
DAC, this tool can convert the digital signals derived from the USB port, an analog signal, which you can connect to the amplifier to the ahirnya you can hear the speaker
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| Click to view larger. | Figure 1 |
As you can see on the schematic in Figure 1 above, which is the heart of the circuit is IC USB DAC PCM2902 made by Texas Instrument, other than that I also added a digital SPDIF output isolation transformer on from this series. 2902 PCM encoding decoding work on the principle that generally abbreviated as word CODEC.
The new circuit will work when the USB input port terminal in the circuit connected to the computer, at this voltage 5V on the USB port of any computer will be triggering the circuit to begin work, and vice versa when the computer is turned off then the circuit will be in standby mode to wait until there is more tension 5V from USB port of computer.
When the received voltage is 5V USB port the computer then the circuit will begin to receive the digital data files during the grace period of 1 ms, all data received during the period of time of 1 ms is called a frame, the data in the first frame is stored in a memory buffer that is in the PCM2902, then the circuit will start the second frame as well as long lead times for 1mS, 1mS a second after the first data from the file will be converted into analog signals for analog terminal is then removed through out the pin 15 and 16 of the PCM2902, other than that this digital signal simultaneously will also excreted through the DOUT terminal pin 25 of the PCM2902 DAC to be connected to older products that do not have a USB input terminal.In addition to functioning as a DAC, PCM2902 actually also has other functions such as setting volume level and ADC, but the circuit that I developed is only aimed for the ADC and the conversion from USB to SPDIF.
Proposed Power Supply For USB SPDIF DAC
Power Supply that I use in this project using the configuration has been proven able to tame the hum in the tube 26, the power supply has karakater very stable, low noise and low impedance, but complicated to make, so for the purposes of this project I recommend another series that is not as complicated Heater power supply 26, but the quality is still better than most of the power supply kit used in the DAC in general, Figure 2 below is the recommendation power supply for USB DAC this project.
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| Click to view larger. | Figure 2 |
1. Diode bridge and capacitor input filter
2. TL431 as the reference voltage
3. OP Amp OP27 as the error amplifier
4. BD139 transistor as a pass transistorThis configuration is basically the general configuration of a linear regulator series, very much the regulator IC using this configuration, but the circuit in Figure 2 above has several advantages that are not owned by the regulator circuit in the form of ICa) high stability, since it uses a reference voltage source of good quality is TL431, and therefore not in a package with a pass transistor, the heat of the pass transistor can not seep into the source of reference voltage and makes it unstable, this sort of thing happens in IC voltage regulator.b) Using the Op Amp high quality, which in this case OP27, so it is not easy to oscillate as the OpAmp used in the regulator IC.c) If there is a chance you could also replace the TL431 or OP27 Op Amp voltage source and another that is expected to be better than either of these components.
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| Series of the finished PCB, top view |
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| IC PCM2902 |
Wednesday, November 5, 2014
USB Powered Audio Power Amplifier
This circuit of multimedia speakers for PCs has single-chip-based design, low-voltage power supply, compatibility with USB power, easy heat-sinking, low cost, high flexibility and wide temperature tolerance. At the heart of the circuit is IC TDA2822M. This IC is, in fact, mono-lithic type in 8-lead mini DIP package. It is intended for use as a dual audio power amplifier in battery-powered sound players. Specifications of TDA2822M are low quiescent current, low crossover distortion, supply voltage down to 1.8 volts and minimum output power of around 450 mW/channel with 4-ohm loudspeaker at 5V DC supply input.
An ideal power amplifier can be simply defined as a circuit that can deliver audio power into external loads without generating significant signal distortion and without consuming excessive quiescent current. This circuit is powered by 5V DC supply available from the USB port of the PC.
When power switch S1 is flipped to ‘on’ position, 5V power supply is extended to the circuit and power-indicator red LED1 lights up instantly. Resistor R1 is a current surge limiter and capacitors C1 and C4 act as buffers. Working of the circuit is simple. Audio signals from the PC audio socket/headphone socket are fed to the amplifier circuit through components R2 and C2 (left channel), and R3 and C3 (right channel)
When power switch S1 is flipped to ‘on’ position, 5V power supply is extended to the circuit and power-indicator red LED1 lights up instantly. Resistor R1 is a current surge limiter and capacitors C1 and C4 act as buffers. Working of the circuit is simple. Audio signals from the PC audio socket/headphone socket are fed to the amplifier circuit through components R2 and C2 (left channel), and R3 and C3 (right channel)
USB Powered Audio Power Amplifier Circuit Diagram:
Potmeter VR1 works as the volume controller for left (L) channel and potmeter VR2 works for right (R) channel. Pin 7 of TDA2822M receives the left-channel sound signals and pin 6 receives the right-channel signals through VR1 and VR2, respectively. Ampl i f ied signals for driving the left and right loudspeakers are available at pins 1 and 3 of IC1, respectively. Components R5 and C8, and R6 and C10 form the traditional zobel network. Assemble the circuit on a medium-size, general-purpose PCB and enclose in a suitable cabinet. It is advisable to use a socket for IC TDA2822M. The external connections should be made using suitably screened wires for better result.
Sunday, September 7, 2014
USB Charger For Lithium Ion battery
USB Battery Charger For Lithium Ion battery with the LM3622 is a series of lithium ion battery charger. This charger circuit operates using power from the USB source PC.
Current consumption of a series of USB Battery Charger For Lithium Ion battery with 400mA LM3622 is limited by R1, so it does not exceed the current maximum limit that can be given by a USB computer. Brains from USB Battery Charger For Lithium Ion battery with IC LM3622 , it is a national of having special technical specification charger for lithium ion batteries.
In a series of USB Battery Charger For Lithium Ion with LM3622 R1 0.25 Ohm value that serves to limit the charging current 400mA to the battery. Q2 and Q1 is the last part of the USB Battery Charger For Lithium Ion battery with the LM3622. In principle, USB Battery Charger For Lithium Ion with LM3622 identify the condition of the battery full charged battery voltage via pin 6 LM3622. USB Series Lithium Ion Battery Charger For LM3622 is equipped with a switch to select the battery that was in charge of 2.7 volts or 2.1 volts.
Monday, August 25, 2014
USB battery Charger circuit
This is usb Battery charger schema.By using this schema you can charge your batteries.Here you can charge only 3V batteries.Dont connect more than that.Here I have used common Ic LT1301.
Note
# Build this on a PCB
Sunday, August 24, 2014
USB Cellphone Charger
This is the schematic diagram of cellphone charger schema which connecter to the USB as main power. Whit this schema, you can charger your cell phone from USB port in your PC or notebook.
The majority of the cellphones battery is appraised 3.6 volts at 1000 to 1300 mah. These battery packs have 3 Nimh or Lithium cells having 1.2 volt rating. Generally the battery pack requires 4.5 volts and 300-500 mA current for quick charging. Anyway, low present charging is better to build the proficiency of the battery. The schema depicted here gives 4.7 directed voltage and sufficient present for the moderate charging of the cellphone.
Transistor T1 is utilized to give the regulated output. Any medium power NPN transistor like TIP122, Cl100, BD139 could be utilized. Zener diode ZD controls the output voltage and D1 protects the polarity of the output supply. Front end of the schema ought to be joined with A type USB plug. Connect a red wire to pin1 and black wire to pin 4 of the plug for easy polarity identification. Connect the output to a suitable charger pin to connect it with the mobile phone. After assembling the schema, insert the USB plug into the socket and measure the output from the schema. If the output is OK and polarity is correct, connect it with the cellphone.
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