Published:2011/5/5 19:21:00 Author:TaoXi | Keyword: Programmable, gain amplifier
The programmable gain amplifier circuit can amplifies, transforms and filter the analog signal, and interconnects the multiple function-modules of the device, and reconstructs the circuit, also it can adjust the circuit's gain, bandwidth, and threshold.
The programmable gain amplifier circuit composed of the AD7523 is as shown in the figure. The circuit's gain is controlled by the 8-bit data to ensure the gain is between 1 to 256, as from the D7 (MSB) there is only one high-level voltage, so it is able to make 6dB as the step length, from 6dB to 42 dB. The AD7523 has the analog switch and R-2R ladder network, the rated resistance is 5~20kΩ, the center value is 10kΩ. If you input the signal from RFB port, the side input resistance will be low, so we connect the buffer amplifier Al before the RFB port as the inverter. If you input from the Al's same-phase port, you can get the same-phase signal. For the variable gain amplifier, if the gain is high, the imbalance voltage is high, so you need to adjust the Op amp to zero and particular pay attention to the output of Al. We usually do the gain calibration on the RFB port series potentiometer RP2. The set gain of op amp A2 is higher, the closed-loop frequency response is worser because the negative feedback of op amp A2 can be changed. We need to use the op amp with narrow gain variable range or good open-loop frequency feature. For small power or accurate op amp, the AC characteristics are sacrificed, so we should pay more attention when we input the signal of thousands Hz. (View)
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Published:2011/5/5 20:59:00 Author:Ecco | Keyword: Single-chip , microcomputer , integrated circuit
PCA84C-440/441 is the single-chip microcomputer integrated circuit produced by Philips company, it is widely used in domestic and imported large screen color TV, such as Philips and other color television.1. The internal block circuit diagram and pin functions PCA84C-440/441 IC uses 42-pin dual in-line package, the internal block circuit diagram and pin functions are shown as the chart. The internal block circuit diagram of PCA84C-440/441 integrated circuit and pin functions and signal flowing2. The typical application circuit The control system typical application circuit composed of PCA84C-440/441 integrated circuit is shown as the chart. The typical application circuit of PCA84C-440/441 integrated circuit 3.PCA84C-440/441 operating parameters The each pins operating parameters of PCA84C-440/441 integrated circuit are listed in Table. The operating parameters of PCA84C-440/441 integrated circuit
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Published:2011/5/5 18:55:00 Author:TaoXi | Keyword: audio frequency, AGC, amplification
The audio frequency AGC can track and keep watch over the preamplifier's output audio signal voltage level, when the input signal increases, the AGC circuit automatically reduces the gain of the amplifier; when the output signal reduces, the AGC circuit automatically increases the gain of the amplifier to keep the best level of the signal which is got into the A/D, and also it minimizes the reduction wave. The audio frequency AGC amplification circuit is as shown in the figure, this kind of amplifier's dynamic range is greater than 50dB, the output distortion is very small, and it has some points of advantages such as starts fast, decay slowly. You can adjust the voltage level of the circuit input 40~20mV and output 0~1.2V, it has the single power supplier, and the current consumption is less than 1mA(5V voltage). VT2 and VT4 are the P-channel JEFT, it constitutes the equivalent resistor divider with R2, R3, R4 (R10, R11, R12), also it accesses to the input circuit. When the input voltage level is less than 40mV (peak-peak), the input voltage assigns between R2 and R3,R4 equally. A1's output amplitude is not enough to conduct the positive peak detector VT2.
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Published:2011/5/5 21:41:00 Author:Ecco | Keyword: single-chip , microcomputer , integrated circuit
PCA841P-177 is a single-chip microcomputer integrated circuit produced by Philips, it is widely used a variety of large screen color TV, which is assembled by Philips movement. 1. Features of functionPCA841P-177 is mainly composed of central processor (CPU), clock oscillator circuit (master clock, the clock display), key decoding circuit, I2C bus control circuit, infrared remote control command signal processing circuit, the screen displays character signal generation and processing circuit, and other control and auxiliary functions circuit. 2. Pin functions and data PCA841P-177 IC uses the package with 42-pin in double rows, the pin code letters and data are listed in the table, the internal block diagram and pin functions and signal flowing are shown as the chart. PCA841P-177 IC pin letter code and data PCA841P-177 IC's internal block diagram and pin functions signal flowing
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Published:2011/5/5 9:17:00 Author:TaoXi | Keyword: pincushion distortion, correction, scanning
The TA8859P pincushion distortion correction and scanning integrated circuit is produced by the TOSHIBA company that can be used in the imported or domestic large-screen color TV.
The TA8859P has the east & west pincushion correction field frequency parabolic wave signal processing circuit, the field scanning circuit.etc, the pin functions and data is as shown in table 1.
Table 1 The pin functions and data of the TA8859P (View)
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Published:2011/5/5 20:44:00 Author:Ecco | Keyword: I2C , bus control, memory , integrated
PCF8581P is the I2C bus control electricity erasable reading memory integrated circuit produced by Philips, it is widely used in large screen color TV and other video, audio, air conditioners and other micro-computer control system. 1. Features of function PCF8581P IC is embedded CMOS 8 Kbit E2PROM read memory and I2C bus control interface circuit. Typical application circuit is shown as the figure. 2. Pin functions and data PCF8581P integrated circuit uses 8-pin dual in-line package, the pin functions and data are listed in Table. PCF8581P IC pin functions and data
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Published:2011/5/5 9:10:00 Author:TaoXi | Keyword: integrated block, typical application
The TDA4860 is designed as one kind of field scanning output integrated circuit that can be used in the color televisions and computer monitors, and this device is produced by the PHILIPS company.
1.Features
The TDA4860 has the field excitation circuit, the field output circuit, the pump roar source voltage control circuit, the protection circuit, the positive and negative symmetrical voltage power supply circuit and other circuits.
2.Pin functions and data
The TDA4860 is in the 9-pin single in-line package, it can be used in the Lenovo and Philips series color monitors, the pin functions and data is as shown in table 20.
Table 20 The pin functions and data of the TDA4860
2. Typical application circuit
The typical application circuit of the TDA7057AQ is as shown in figure 20.
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Published:2011/5/5 4:04:00 Author:Ecco | Keyword: 0 ~ 5V , line graph, indicator
0 ~ 5V line graph indicator circuit composed of LM3914 series of point / line LED display driver integrated circuit.
LM3914LED display driver IC is widely used, the external components and wiring changes may constitute a variety of display and alarm circuits, cascade using may constitute a multi-level LED display.
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Published:2011/5/5 8:53:00 Author:TaoXi | Keyword: Micro-power, break-type, anti-theft alarm
The Micro-power break-type anti-theft alarm circuit is as shown:
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Published:2011/5/5 4:13:00 Author:Ecco | Keyword: Christmas light
The chart shows the Christmas lights circuit composed of simple, inexpensive CD4069 six-inverter, it can control 4 loops with 200 light-emitting diodes (50 per channel), and they are directly driven by the 220V power supply and does not need power transformer. Ater the power supply rectified by VD1 ~ VD4 bridge, it is filtered by the partial pressure on R1, R5 and C1, the two ends of the C1 will get a DC voltage with about 6V for IC1 (CD4069). D5 and D6 form gate low-frequency oscillation. The frequency is adjusted by RP. Its output passing a combination shaping by D1 ~ D4 could control the four transistors with high back pressure (2N3440/2N3439) VT1 ~ VT4. The per channel of VT1 ~ VT4 uses 50 LEDs as Illumination load. RP2 ~ RP5 are used to adjust the VT1 ~ VT4 to adapt to different working conditions of the lantern load.
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Published:2011/5/5 4:18:00 Author:Nicole | Keyword: power amplifier
AN7112 is a audio power amplifier integrated circuit which is produced by Panasonic, it is used in 3-5.5 inch miniature TV and computer audio system.
1, internal circuit block diagram
AN7112 integrated circuit contains singal input, audio motivation single-ended pull-push amplifier circuit, the integrated block internal circuit block diagram is shown as the figure1.
Figure1 is the AN7112 integrated block's internal circuit block diagram
2, pin function and data
AN7112 integrated circuit adopts one line ⑨ foot package, the integrated circuit's pin function and data is shown in the excel 1.
Excel 1 is the AN7112 integrated circuit's 5 foot function and data. (View)
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Published:2011/5/5 8:38:00 Author:TaoXi | Keyword: voltage, two-way, over-restriction, alarm protection
The voltage two-way over-restriction alarm protection circuit is as shown:
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Published:2011/5/5 8:50:00 Author:Nicole | Keyword: microcomputer, dialing
UM9169 is microcomputer dialing integrated circuit. It is used in all kinds of communication telephones.
1, functions and features
UM9169 integrated circuit contains double audio frequency dialing singal process circuit, key switch singal encoding and decoding and squelch control circuit.
2, pin function and data
UM9169 integrated circuit's pin function and data is shown in the table 1-1.
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Published:2011/5/5 8:23:00 Author:TaoXi | Keyword: Practical, gate contro, anti-theft, alarm
The practical gate control anti-theft alarm circuit is as shown:
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Published:2011/5/5 8:20:00 Author:TaoXi | Keyword: system control, microcomputer
The TB2003-004FN system control microcomputer integrated circuit is produced by the TOSHIBA company, and it can be used in the top grade walkman cassette player applications, and the pin functions and data is as shown in table 1.
Table1 The pin functions and data of the TB2003-004FN (View)
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Published:2011/5/5 8:33:00 Author:Nicole | Keyword: microcomputer, dialing
UM91210 is microcomputer dialing integrated circuit. It is used in all kinds of communication telephones.
UM91210 integrated circuit contains pulse/double audio frequency compatible dialing, key switch singal encoding and decoding circuit and so on, the integrated circuit's pin function and data are shown in the excel 1-1.
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Published:2011/5/5 8:36:00 Author:Nicole | Keyword: microcomputer, single chip dialing
UM91230C、UM91230D are microcomputer single chip dialing integrated circuits which are produced by United Micro Company, as dialing circuit, it is used in communication equipment. This IC adopts 22-foot dual in-line package, the integrated circuit's pin function and data are shown in the excel 1-1.
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Published:2011/5/5 8:11:00 Author:TaoXi | Keyword: Automatic, ignition, gas, blow-off alarm
The Automatic ignition gas blow-off alarm circuit is as shown:
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Published:2011/5/5 8:27:00 Author:Nicole | Keyword: microcomputer, single chip dialing
UM91260A、UM91260C are microcomputer dialing integrated circuit, as dialing circuit, it is used in communication equipment.
UM91260A、UM91260C have the function of: re-dial 32 bits numbers(double audio type is 31 bits), store 10 16-bit numbers, the integrated circuit's pin function and data are shown in the excel 1-1.
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Published:2011/5/5 7:54:00 Author:TaoXi | Keyword: Thunder, warning device
The Thunder warning device circuit is as shown:
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