Showing posts with label w. Show all posts
Showing posts with label w. Show all posts
Thursday, August 1, 2013
1 W Home Stereo Amplifier Rise
This is a one watt home stereo amplifier module project using the KA2209 IC from Samsung, which is equivalent to the TDA2822. It operates from 3-12V DC & will work from a battery since the dormant current drain is low. It requires no heat sink for normal use. The input & output are both ground referenced. Maximum output will be obtained with a 12V power supply & 8 ohm speaker, however it is suitable for driving headphones from a supply as low as 3V.
The Specifications of the home stereo amplifier :
The Specifications of the home stereo amplifier :
D.C. input : 3 – 12 V at 200 – 500 mA max
Idle current : approx. 10 mA
Power output : > 1 Watt max. 4-8 ohms, 12V DC
Freq. Resp. : approx. 40 Hz to 200 kHz, 8 ohm, G=10
THD : < 1 % @ 750 mW, 4-8 ohm, 12V
Gain : approx. x10 (20 dB) OR x100 (40dB)
S/N ratio : > 80 dB, G = 20 dB
Sensitivity : < 300 mV, G = 20 dB
Input Impedance : approx. 10 k ohm
Idle current : approx. 10 mA
Power output : > 1 Watt max. 4-8 ohms, 12V DC
Freq. Resp. : approx. 40 Hz to 200 kHz, 8 ohm, G=10
THD : < 1 % @ 750 mW, 4-8 ohm, 12V
Gain : approx. x10 (20 dB) OR x100 (40dB)
S/N ratio : > 80 dB, G = 20 dB
Sensitivity : < 300 mV, G = 20 dB
Input Impedance : approx. 10 k ohm
Description
The gain is adjustable from ten to 100, i.e. twenty to 40 dB. Start with feedback resistors R1 and R3 of 1k ohm, this will give a gain of ten which ought to be adequate for most applications. In case you need more gain, you can remove resistors R1 and R3.This will give a gain of about 100, or 40 dB.The input attenuation can be adjusted by the potentiometer which can be used as a volume control. The IC gain ought to be kept as low as necessary to accomplish full output, with the in put potentiometer and your signal source at maximum.
Voltage Gain = 1+ R1/R2 = 1+R3/R4, however the maximum gain with no outside feedback is about 100, or 40dB. (GdB = 20log Gv)
This will keep the signal to noise ratio as high as feasible. Additional gain provided by the amplifier will reduce the S/N ratio by a similar amount, since the input noise figure is constant. Other values for R1 and R3 of between 1k and 10k ohm can be used if an intermediate gain level is necessary.
This will keep the signal to noise ratio as high as feasible. Additional gain provided by the amplifier will reduce the S/N ratio by a similar amount, since the input noise figure is constant. Other values for R1 and R3 of between 1k and 10k ohm can be used if an intermediate gain level is necessary.
If driving a pair of headphones, you may also need a 100 ohm resistor in series with each output to reduce the output level, depending on headphone impedance & sensitivity. Make positive you start with the volume right down to check. Numerous headphones may be driven from the amplifier in the event you wish, since most headphones have at least 16 ohm impedance, or more often 32 ohm.
There are only a few outside parts, the IC contains most of the necessary circuitry. R1,R2 and R3,R4 are the feedback resistors. C1 provides power supply decoupling. C2 and C3 are the input coupling capacitors, which block any DC that might-be present on the inputs. C4,C5 block DC in the feed back circuit from the inverting inputs, and C6,C7 are the output coupling capacitors. C8, R5 and C9,R6 act as Nobel networks providing a high frequency load to maintain stability at frequencies where loud speaker inductive reactant may become excessive. The pot provides adjustable input level attenuation.
Wednesday, May 15, 2013
Compact 150 240 W Power Supplies offer up to 200 peak power
September 10, 2012 - Exhibiting 91% efficiency, TDK-Lambda ZWS-BP series has universal 85-264 Vac, 47-63 Hz input; can operate with DC input over 120-370 Vdc range; and offers outputs of 24, 36, or 48 Vdc. These open-frame, single-output power supplies, able to withstand 3 kVac input-to-output, have profiles from 1.46-1.65 in. and occupy 2.95 x 6.3 in. or 3.31 x 7.09 in. footprint. With convection cooling, RoHS-compliant products provide up to 150 or 240 W of output.
DK-Lambda Unveils Compact 150 & 240 Watt Power Supplies with up to 200% Peak Power
Convection Cooled (No Fans) - 91% Efficient - For Industrial, ITE, Comms & Kiosk Applications
San Diego, CA - TDK Corporation announces the new TDK-Lambda ZWS-BP series of compact, open-frame, 150W and 240W power supplies. These single-output supplies have a low profile of 1.46" to 1.65" and compact footprints of 2.95" x 6.3" or 3.31" x 7.09". Moreover, these units can provide a peak output power of up to 200% (for motors, pumps, etc.), making them an ideal choice for applications in industrial, gaming, point-of-sale, test & measurement, LED signage, and communications equipment.
These new TDK-Lambda AC-DC supplies feature a universal 85-264Vac, 47-63Hz input, enabling them to be used anywhere in the world. The ZWS-BP is designed to withstand 3kVac, input-to-output. In addition, they can operate with a DC input over the range of 120-370Vdc. The supplies are available with an output voltage of 24V, 36V or 48Vdc and include an onboard output adjustment potentiometer.
With convection cooling (no fans required), these supplies provide up to 150 or 240-watts of output power. The operating temperature range is from -10°C to +70°C with derating above +50°C. The output is floating so it can be used as either a positive or a negative polarity. The power-saving efficiency is up to 91%. Standard features include overvoltage and overcurrent protections. Optional remote On/Off connections are available to allow for remote control of the supply.
The ZWS-BP series is an extension of the very successful ZWS series, which were employed in the high-definition Diamond Vision video displays that were built by Mitsubishi Electric and have been used to power some of the worlds largest LED displays located at the Cowboys Stadium (Texas), Yankee Stadium (New York) and many other global sites. TDK-Lambda power supplies were selected for their long-term reliability and quality.
The ZWS-BP series feature global ITE and general purpose safety agency certifications per UL/CSA/EN60950-1, EN50178 (OV II), are CE Marked, meet the conducted and radiated EMI requirements of EN55011/EN55022-B, VCCI-B and FCC Class B, which is much tougher than Class A. These units are RoHS compliant and include a 5-year warranty, which is one of the longest-term warranties available in this power range.
Thursday, April 11, 2013
11 W Stereo or 22 W Mono Power Amp
Integrated AF power amps have seen great improvements in recent years offering improved power and easier use. The TDA1519C from Philips contains two power amplifiers providing 11 W per channel stereo or 22 W mono when the two channels are connected in a bridge configuration. The special in-line SIL9P package outline allows the chip to be conveniently bolted to a suitable heatsink. The TDA1519CSP is the SMD version, in this case the heat sink is mounted over, and in contact with, the top surface of the chip.
11W Stereo Amplifier Circuit Diagram The operating voltage of this device is from +6V to +17.5V. The two channels of the amplifier are different in that one channel, between pins 1 and 4, is a non-inverting amplifier, while the other between pins 9 and 6 is an inverting amplifier. It is therefore necessary in stereo operation, to wire the speakers so that one of them has its polarity reversed. Each amplifier has an input impedance of 60kΩ and a voltage gain of 40dB, i.e. 100 times. When both amplifier are used in a bridge configuration, the inputs are in parallel so that the input impedance will be 30kΩ.
22W Stereo Amplifier Circuit Diagram A combined mute/standby function is provided on pin 8. In its simplest form this can be connected to the positive rail via a switch. When the switch is open the amplifier will be in standby mode and current consumption is less than 100µA. When the switch is closed, the amplifier will be operational. A circuit is also shown that uses the mute input to prevent the annoying switch-on plop heard when power amps are first switched on This is caused by the rush of current to charge capacitors C1 and C2.
Mute/Standby Switch Circuit Diagram
The circuit shown generates a ramp voltage, which is applied to pin 8. At switch on, as the voltage rises from 3.3 V to 6.4 V, the amplifier will switch out of standby mode and into mute mode allowing C1 and C2 to charge. Only when the ramp voltage on pin 8 reaches 8.5V will the amplifier switch into active mode. Protection built into the TDA1519C would seem to make it almost foolproof. The two outputs can be shorted to either of the supply rails and to each other. A thermal shutdown will prevent overloading and the power supply input is protected against accidental reversal of the supply leads up to 6V.
Author : G. Kleine - Copyright : Elektor Electronics
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