Basics
Young enthusiasts started his electronic technology, we might start with the most innovative electronic devices - music and voice integrated circuits start from the beginning to close to new knowledge, new technology, electronic technology from the high-level entry, which take into the electronic world, the colorful Grand View Park, to experience and awareness of the magic and mystery of e-science. If the "great use of small chips" of the group of articles is an interesting attempt by 30 small circuit, built into a kaleidoscope of diverse and changing e-friends dedicated to young people, then "Quick Introduction to Voice IC Trilogy", the is sought from the foundation of knowledge, information and practical examples of the circuit and so on starting, so that young fans in the practice and mastery of certain preliminary study of electronic knowledge and skills at an early date into the electronic world.
We usually see and voice access to integrated circuits, most of the package shown in Figure 1. Figure 1 (a) is a dual in-line plastic package IC (DIP), commonly known as a hard circuit package, pin count is divided into 8 feet by 14 feet, 16 feet and so on, each pin has a different function. The more often pin, the greater the volume of integrated circuit chips, the circuit functions are stronger, the higher the value, of course. Figure 1 (b) integrated circuit package are printed board (COB), commonly known as soft-package circuit, which is the integrated circuit chip packages on printed circuit board directly to a simple semiconductor integrated device. Soft circuit packaging technology is simple, short production cycle, lower cost, and can be repaired many times, so the pass rate is very high. Now widely used in consumer electronic products such soft package circuit.
(B)
Voice integrated circuit chip, also known as the die, which uses multi-layer mask technology and digital voice circuit unit voice mask in semiconductor chips, the manufacturing process is very complex production cycle of about 45 days. Mask before the user must make the following choices: 1. Trigger edge select a trigger (EDGE), triggering a circuit operation time, even if the trigger signal continued to maintain the action only once;-level trigger (LEVEL), the trigger signal and maintained a sustained, the voice output until the trigger to stop repeating the last paragraph shall cease to voice output is completed. 2. Output to select a continuous output (UNHOLD), trigger the action of a stop, when the segment after the speech to continue to output to stop; non-continuous output (HOLD), a stop trigger action, voice output stopped immediately. 3. Touch trigger to select a loop playback (SEOUENTIAL), a voice output for each time the contents of the trigger, loop sections of broadcast speech; speed the whole place (PLAY ALL), a voice in turn trigger all of the paragraphs after the broadcast; Random playback (RING), a trigger output after the irregular voice sections. 4. Back-cover front / no back-cover front to select a paragraph in the existing before the end of the speech, but also trigger the other a voice, the voice front where both players to have stopped immediately after the speech will be overshadowed by the preceding paragraph and playback, which is called the back-cover front. 5. Matrix trigger / trigger select a matrix keyboard trigger (MATRIX), namely the use of output and input points of the criss-cross the trigger input; keyboard trigger (KEYBOARD), both the use of ten digit keys and a median composition of the number of segments to be triggered. The two trigger voice key trigger for more than twenty segments. 6. Light-emitting diode means to select a voice output, a fixed frequency of flashing light-emitting diodes; the light-emitting diodes synchronized with the audio output signal strength of the flash; and voice output signal with a synchronization level signal output to drive LEDs or generated signal cascade. 7. Output current can select a mask to select the output power (COUT) were 1.5mA, 3mA, and 4.5mA and so on, output current, the chip's power consumption is small, and the output volume small; the other hand, the output current, chip power is greater, the output volume to small.
Sampling frequency of speech signals is to determine the sound quality of voice circuits the most important factor. In general, the sampling frequency must be voice-band width of more than 2 letters, for example, to save the maximum frequency bandwidth of the spectrum 6KHz, when the minimum sampling frequency must be 2 × 6KHz = 12KHz. Usually the line bandwidth 3KHz, whichever if the phone sound quality, 7KHz the sampling frequency can meet the requirements, and deal with the general phoneme, with 12KHz sampling can basically reach the level of high fidelity sound quality. The number of voice circuits a variety of synthetic methods, the most commonly used two methods to clear shape memory synthesis method and the parameter analysis. Table 1 lists the main ways of speech synthesis. Table 2 lists a number of little-known list of speech synthesis circuit, for readers to choose. HT81230 voice circuit below to an example, the main parameters of voice circuits and applications circuits.
Table 1

Rule synthesis method   
Extremely difficult    This will be the smallest unit of speech into phonemes, the other calibration stress and intonation
Table 2

Figure 2 shows the type of 2.8 seconds for the HT81230 voice integrated chip pin graphs, tables 3, the pin coordinates of its data, HT81230-type chip dimension is 2160 × 2450 (μm) 2, Figure 3 is a type of chip HT81230 external wiring diagram. Figure 4 HT81230 IC pin plastic dual in-line arrangement diagram, typical application circuit shown in Figure 5. Table 4 lists the pin functions HT81230 brief description of each, Table 5 HT81230 integrated circuit electrical parameters. Each model should be given the speech IC 3 Figure 3 Table. Beginners through Figures 2 to 5, Table 3 to Table 5 to master HT81230-based voice and application of the basic characteristics of integrated circuits. According to Figure 2, Figure 3, we can design according to the actual needs of a variety of printed circuit board (Figure 6), very useful and flexible.
Table 3 Unit: μ m

Table 4

Table 5

 

The circuit in Figure 6, HT81230 voice ICs IC, a total of 10 pads, aluminum wire press welder by the microcomputer thinner than human hair using a special metal wire, respectively, bonding them in the printed circuit board, professional by microscopic examination to confirm correct welding, and then mixed with black epoxy glue chip package (part of the black circle in Figure 6). HT81230 of 10 pins, respectively, in Figure 6, the printed circuit board 10 connected to printed circuit, which receives power supply VDD pin 1 positive (+) terminal, the first 6 VSS pin power supply is negative (-) terminal, 3V DC power through the two-pin power supply to the IC. Section 3 4 feet OSS2 and external oscillation resistor between pin OSS1 ROSC, appropriate adjustments to the resistance of the resistor, the frequency of the internal IC can be changed to achieve the playback speed of adjustment. Section 5 feet FLAG VD light-emitting diode through a resistor to the power positive terminal, when the circuit when playing audio, VD light means there are 3, 1 species is the playback duration of light, the first 2 is accompanied by strobe playback produces 3HZ , No. 3 is a shining moment about the end of voice playback, this 3 way light mask before the select OK. 2 output pin AUD first audio signal amplified by NPN silicon transistor, 8Ω speaker directly promoting the work. Article 7 ~ ​​10 feet KEY1 ~ KEY4 respectively, then four micro-switches, control the trigger 4 different sounds, voice IC trigger level is divided into high and low 2, HT81230 low trigger.

 

Next, several application circuits described HT81230 for beginners reference.
1. Parallel application circuit shown in Figure 7, the two or more pieces of the same audio content is not connected with the output of the circuit, circuit and connection method. This parallel application circuit, the number of voice segments can be extended.

 

2. Series application circuit shown in Figure 8, the two or more pieces of audio content with a different termination circuit output, LED output circuit FLAG and the next one is connected to the trigger terminal KEY (light emitting diode output mode should be selected 3 above), the first one circuit of the output signal as the first two circuits of the control trigger signal, two circuit in series before and after control. The application circuit can not only extend the length of each speech, but also simplify the circuit. For example: the first a circuit with 4 different storage statement and request broadcast each statement followed by a piece of music, this series can be used to control the circuit.

3. Automatic power-play circuit application circuit shown in Figure 9, the circuit of the difference is the trigger in the IC and the VSS client KEY 0.1μ F between the series with a capacitor and 1.2MΩ resistance, when the circuit is powered on, the role of the capacitor , IC is an instant trigger, voice finished playing automatically stop working.

4. Loop power circuit circuit shown in Figure 10, when the trigger end of KEY direct access VSS, when power on, the circuit automatically loop until the power off.

5. Adjust the volume application circuit of Figure 11, an external audio output AUD 1KΩ trim resistor and 10μ F capacitor, which can change the transistor's input voltage, in order to achieve the purpose of adjusting the volume.

6. Differential amplifier circuit shown in Figure 12, type NPN silicon transistor from the 8050 and 8550-type PNP silicon transistor and rectifier diode IN4148-type transistors, etc. constitute the differential amplifier circuit, the circuit output sound particularly loud.

7. External power amplifier circuit shown in Figure 13, through the sliding contacts 10KΩ potentiometer, external LM386, TDA2003 power amplifier integrated circuits, etc., in order to obtain greater output power.

In addition, light control, voice circuits and other applications, due to limited space, stop here.