2SC3320 HIGH VOLTAGE HIGH SPEED SWITCHING

The 2SC3320 is a triple diffused planer type high voltage high speed switching.

2SC3320 absolute maximum ratings: (1)VCBO: 500 V; (2)VCEO: 400 V; (3)VCEO(SUS): 400 V; (4)VEBO: 7 V; (5)IC: 15 A; (6)IB: 5 A; (7)Pc: 80 W; (8)Tj: +150 ℃; (9)Tstg: -65 to +150 ℃.

2SC3320 features: (1)high voltage, high speed switching; (2)high reliability.

C-52 Evaluation Board 62256

A circuit diagram of the C-52 EVB is depicted in Figure 1. See at EA pinfirst, I put EA to Vcc configuring the 89C52 started internal code executionwhen reset. The first 8kB code space, 0000H-1FFFH is then be a monitorprogram, i.e., PAULMON2. A 32kB SRAM 62256 uses 15 lines address, A0-A14,while A15 of the 89C52 connects inverter gate, 74HC00, to CE pin. Thismakes the address space of the SRAM to be 8000H-FFFFH, i.e., A15 must be'1' to enable 62256. See OE pin, RD and PSEN are tied together with ANDgate made by two NAND gates. This makes the address space 8000H-FFFFH seenby 89C52 can be external code and data memory. Thus during in monitor modethat runs under PAULMON2, user may write hex code or download intel HEXfile to 62256. When jump from PAULMON2 to user program and run user program,this space is then be seen by 89C52 as a code space. Since P0 and P2 areused for connecting external RAM, left P1 and P3 for experimenting withreal world interfacing through input/output port. Nowadays there are manyperipheral chips that use serial protocol, say I2C, SPI. Thus only twoport is surely enough.

Serial EEPROM Interfacing - 24C08

24C08 
Many designers today are implementing embedded systems that require low cost non-volatile memory. Microchip has addressed this need with a full line of serial EEPROMs, in a variety of memory configurations, using the industry-standard 2- or 3-wire communication protocols.

HIGH CURRENT DC DEVICES TIP122

  


The Controlling Multiple LEDs Tutorial uses the 2N3904 small current transistor. This works well for controlling additional relatively small current devices with the Arduino. You may want to use the Arduino to control a DC powered device that draws more current that the 2N3904 transistor can supply. A solution for this situation is to use an NPN Darlington Transistor designed for medium power linear switching applications. In this tutorial we will use a TIP122 transistor, which can power devices up to 100VDC at 5 Amps. This can be used to power devices such as motors, solenoids and fans, where the only necessary operation control operation is ON and OFF (see the H-Bridge Tutorial for bi-directional rotation and speed control of DC motors.)

The circuit is identical to the 2N3904 transistor circuit - the base of the transistor (PIN 1) is connected to the Arduino output pin (D6) through a 1K OHM resistor. The emitter (PIN3) is connected to ground and the collector (PIN2) is connected to one end of the coil of the device being driven (in our example we have a 12VDC Solenoid connected). The other end of the coil is connected to the +12VDC external power supply (the ground from this power supply is connected to a common ground with the Arduino - this is necessary for the transistor to function). It is very important to put a diode across the coil of the device being powered to protect the control circuit from a potential voltage spike that can be created when current is released from the device being powered.

Multi Output DC to DC Converter LM2596

This is the circuit diagram of DC to DC converter based LM2596, the circuit has a single input supply and multiple voltage outputs. The circuit has an input voltage range of 15V to 40V. It has 5 outputs: 3.3V at 1.5A; +12V and −12V at 50 mA each; and +5V and −5V at 50 mA each. The 3.3V, +5V and −5V outputs are regulated with ±5% accuracy over line and load variations.

Circuit parts list:

    Cin : 220 μF, 50V, Nichicon UPL1H221MPH
    C1: 270 μF, 63V, Nichicon UPL1J271MRH
    C2, C3: 47 μF, 35V, Nichicon UPL1V470MPH
    D1: MBR360,
    D2, D3: 1N459,
    C4, C5: 0.01 μF
    IC1: LM2596-3.3 (SIMPLE SWITCHER® Step-Down Voltage Regulator)
    IC2, IC3: LM78L05, and LM79L05. (3- Terminal Regulators)
    L1: Custom Inductor with three windings (W1, W2 and W3) with the following specs:

        W1: 47 μH; Peak Current: 2.6A, RMS Current ≈ 2.32A
        W2: Number of turns = 3.4 x Number of turns in W1; RMS Current; 113 mA
        W3: Same as W2

The +12V and −12V outputs are regulated with ±20% accuracy. A typical application of this circuit is where the 3.3V output provides the power to the main circuit which is 3.3V logic, the ±5V outputs power the 5V logic and ±12V outputs provide the bias supply of op-amps.

The efficiency of the circuit with full load at all outputs is 75%. The ripple voltage across the 3.3V output is less than 20 mV and that across the ±12V outputs is less than 30 mV. The ripple across the ±5V is less than 10 mV.

Hardware 74HC164

Stefan Heinzmann's circuit requires only a 74HC164 8 bit shift register and a 10K trimpot to adjust the LCD's contrast.

The AVR's hardware requirements are 3 port pins:
PORTB bit 5 (LCDE) is connected to the E Clock (E) pin on the LCD module.
PORTB bit 6 (LCDDat) is connected to the register select (RS) pin on the LCD module and to the two data inputs (A and B) of
the 74HC164 shift register.
PORTB bit 7 (LCDClk) is connected to the CLK input of the 74HC164 shift register.
Any other three output port bits could be used.
It's a very simple circuit but adding a 0.1µf capacitor between the +5V and ground of the 74HC164 would be a good idea.
If you can't see any characters displayed on the LCD (and you've checked that the hardware and software are working) turn the LCD Contrast pot until you can see the characters.

Multi-purpose dual power supply regulator board AMS1117

All embedded systems require electric power to operate. Most of the electronic components inside them, including the processors, can operate at a wide range of supply voltage. For example, the operating voltage range for the PIC16F1847 microcontroller is 2 to 5.5 V. But there are certain applications where you need a regulated constant voltage to avoid malfunctioning of the circuit or getting erroneous results. For instance, any application that involves analog-to-digital conversion (ADC) requires a fixed reference voltage to provide accurate digital count for input analog signal. If the reference voltage is not stable, the ADC output is meaningless. Here is my latest dual power supply regulator board that provides constant 3.3V and 5.0V outputs from an unregulated DC input (6.5-10V). It is small in size and can be easily enclosed inside the project box along with a project circuit board. It can also be used to power test circuits on breadboard. The board uses two AMS1117 series fixed voltage regulators and receives input power through a DC wall wart or an external 9V battery.

he regulator circuit uses two AMS1117 series fixed voltage regulators, AMS117 5.0 and AMS1117 3.3, to derive constant 5.0V and 3.3V outputs from an unregulated DC input voltage. The circuit diagram of the board is shown below.

Note that both AMS1117-3.3 and AMS1117-5.0 derive input power directly from the unregulated supply voltage, which means each of them can deliver up to 0.8A of current. However, for this particular board it is recommended to limit the output current up to 500 mA maximum. For the safety of the AMS1117-3.3 regulator IC, the unregulated input voltage is also recommended to be within 6.5 to 10.0 V. This board is best to use in a project that is designed tobe powered with a 9V DC from either a PP3 battery or a wall adapter. The PCB is only 1.9″ x 1.4″, and occupies a small area inside the project box.

 

The board doesn’t have any ON/OFF switch, because it may not be useful if this board is enclosed inside the project box. But through-hole pads are provided on the board if you want to add one externally. There are two surface mount pads which are shorted together by default with solder to close the circuit permanently. These must be disconnected if an external ON/OFF switch has to be added.

The regulated output voltages (5V and 3.3V) are accessed through screw terminal blocks. This power supply board can also be used to power breadboard circuits (see the picture below).

 

Full Bridge Inverter with MOSFET - IR2110 gate driver

This is the project to make a grid connected inverter.

For the full bridge inverter circuit i planned to use IRF2807 (75V Vds, 82A Ids) and Two IR2110 for the driver. I never use IR2110 before and failed many time when i want to make a H-Bridge for DC motor last year.

I planned to design the circuit based on this sample project  :

There are some questions about the schematic since the specification is quiet different.

My DC input voltage is 34V (2 series solar panel), The power rating is about 100Watt so the MOSFET should able to drain about 10A max current. The output of the inverter will be connected to 18V - 220V step up transformer. My controller will use hysteresis current control method so the switching frequency is not fixed and varied up to 100kHz.. and i want to isolate (different ground) between my micro controller and power circuit. How can i use the optocoupler to isolate it? is there any optically isolated buffer since i planned to use buffer (micro controller (ATmega 8535, 16MHz -> Buffer IC -> Optocoupler -> IR2110).

Based on the specification, is there any component that i should change?   read before to change the diode to the fast recovery one, and change the resistor value..

If you have to isolate your ground, I would recommend you to use isolation transformer instead of optocoupler. In this, you will no longer need to use high-side capable driver ICs, you will instead use a small gate drive transformer, buffered by the totem-poles.

The transformer is very easy to wind, use small toroid core, about 10mm
outer diameter or even slightly smaller. Make sure that it will not saturate.

Just make sure that you follow the polarities, you already know that of course.

TIP122 Connection Diagram

TIP122



Speed control of permanent-magnet (PM) dc motors with the aid of optical or dc tachometers is generally inconvenient and difficult, particularly on motors with integral gearboxes. The high-speed shaft of the motor that drives the gearbox isn't always accessible and the speed of the geared-down shaft often is too low for tachometers. Described here is a single-supply regulating speed-control circuit that doesn't require a tachometer. It keeps the motor torque high under load by using positive feedback to compensate for the drop caused by armature resistance. In unregulated variable-speed PM dc motor systems, the drop in speed under load is particularly pronounced at low motor-supply voltages. The positive feedback generates a negative resistance that compensates for the nonlinear effects caused by armature resistance. It thereby ensures that the speed-control input voltage (V_i) linearly controls the speed of the motor. Armature resistance compensation is achieved if:

             R_S= R_A/[gain(R₃) / (R₃ + R₄)] - 1

The divider action of R3 and R4 together with the gain reduces the value required for R_s to minimize the power dissipation. C1 and R4 dampen the positive-feedback signal's response time, but they also form a low-pass filter and attenuate the motor current noise fed to the A2 input. The maximum output voltage swing from A2 is approximately V_CC-2 V, and there is a 1.2-V V_be loss by T1. This implies that the supply voltage (V_cc) should be about 5 V above the maximum desired motor voltage in order to allow for extra output drive to the motor under heavy load conditions. A reason-able choice for R_s is approximately R_A/10, and the gain of A2 should be trimmed with RV2 to ensure that the motor's speed does not drop when loaded.

Simple Switch Step Down Regulator Circuit LM2596

The LM2596 series of regulators are monolithic integrated circuits that provide all the active functions for a step-down (buck) switching regulator, capable of driving a 3A load with excellent line and load regulation.
These devices are available in fixed output voltages of 3.3V, 5V, 12V, and an adjustable output version.

Requiring a minimum number of external components, these regulators are simple to use and include internal frequency compensation†, and a fixed-frequency oscillator.

The LM2596 series operates at a switching frequency of 150 kHz thus allowing smaller sized filter components than what would be needed with lower frequency switching regulators. Available in a standard 5-lead TO-220 package with several different lead bend options, and a 5-lead TO-263 surface mount package.

A standard series of inductors are available from several different manufacturers optimized for use with the LM2596 series. This feature greatly simplifies the design of switch-mode power supplies.

Other features include a guaranteed ±4% tolerance on output voltage under specified input voltage and output load conditions, and ±15% on the oscillator frequency. External shutdown is included, featuring typically 80 µA standby current. Self protection features include a two stage frequency reducing current limit for the output switch and an over temperature shutdown for complete protection under fault conditions.

MAX232 product image MAX232 DUAL ELA-232 DRIVERS/RECEIVERS

The physical communication standard defines the signal voltage of -10V for logic '1', and +10V for logic '0'. However in practise, the voltage can be ranging from +/-3V to +/-25V. Not to worry if the measured voltage is not +/-10V. Typical receiver is able detect the incoming signal with voltage as low as +/-3V.
A microcontroller like PIC16F877a uses USART (5V system). The PC (personal computer) that we have in the office/home uses the standard RS232. To enable a microcontroller to communicate with the computer, a RS232 to TTL converter is required.

 

IC chip maker has come up with the integrated circuit for interfacing RS232 with TTL logic (5V for logic 1, 0V for logic 0), making the interfacing work very simple. MAX232 is one of the many IC in the market which helps to convert between RS232 -/+10V and TTL +/- 5V. It is a simple voltage level converter in short. The charge pump design allows the circuit to generate +/-10V from a 5V supply, with the help from the four capacitor. With charge pump to double up the supply voltage for RS232 transmitter, there is no need to design a power supply for +/-10V.
The diagram on the left shows the schematic of the MAX232 IC circuit. It consist of only 4x 1uF 16V electrolytic capacitor, and the MAX232 IC itself. It is that simple. I have include a layout which I always use for PC to PIC16F877a microcontroller, RS232 interface.

Interesting mosfet voltage regulator IRF3205

  The mosfet used was the IRF3205 Enhancement Mosfet. Its function is to boost the current induced into the transmitting coil to increase its distance level. Mosfet ratings; Peak Drain to Source Voltage (VDS)= 55V On Resistance = 8.0 ohm Peak current = 110A when VDS = 10V So the current used was derived using the equation; ION = k (VDS(on) – VDS(th))2 Using the ratings to get the constant k we have, K = 110A/ (10V – 4V)2 K= 110/62 K = 110/36 K = 3.10AV2 Having gotten the constant k as 3.10AV2, we can derive our drain current as; I = 3.10 x (9V – 4V)2 I = 3.10 x 25 I = 77.50A

  The inductance of the inductor to use is derived using the equation; L = n2 x R2/ 9R + 10x Where, L is the inductance N is the number of turns R is the radius of coil X is the distance of turns To get the required reactance of the coil to use, we divide the DC supply Voltage by the Drain Current of the MOSFET. Therefore, XL = 21.21/77.50 XL = 0.27ohm If Reactance of an inductor XL = 2 x 3.142 x f x L, then 0.27 = 6.284 x 50 x L L = 0.27 / 314.2 L = 0.0008593H RECEIVING CIRCUIT: The receiving circuit has basically the receiving coil, half wave rectifier circuit/filter and the voltage capacitor. The value of R is used to set the charging current to a fixed value which is determined by the Charging voltage/ charging current. For this project, the charging voltage was 5V DC. And the charging current required was 500mA. Therefore the value of R will be; R = 5/0.5 = 10ohm

2N3906 PNP General Purpose Transistor

The 2N3906 is the general purpose (PNP Silicon) PNP switching transistor, which is produced by Fairchild Semiconductor.

2n3906 absolute maximum ratings: (1)Collector–Emitter Voltage: 40 Vdc; (2)Collector–Base Voltage: 40 Vdc; (3)Emitter–Base Voltage: 5.0 Vdc; (4)Collector Current — Continuous: 200 mAdc; (5)Total Device Dissipation, TA = 25℃: 625mW; (6)Total Power Dissipation, TA = 60℃: 250 mW; (7)Total Device Dissipation, TC = 25℃: 1.5 Watts; (8)Operating and Storage Junction Temperature Range: –55 to +150℃.

2N3906 features: (1)Capable of 600mW of Power Disspation and 200mA Ic; (2)Lead free finish/ROHS compliant; (3)Epoxy meets UL 94 V-O flammability rating; (4)Moisure sensitivity level 1; (5)Through Hole pakage; (6)Marking: type number.

MC34063 mp3 player charger - Battery charger circuits

This mp3 player charger electronic project circuit diagram is designed using the MC34063 circuit which is a monolithic control circuit delivering the main functions for DC DC voltage converting.

The output voltage of this MC34063 mp3 player charger will deliver a 5 volts output voltage at 660mA output current .
The MC34063 mp3 player charger contains an internal temperature compensated reference, comparator, duty cycle controlled oscillator with an active current limit circuit, driver and high current output switch.
The output voltage is adjustable through two external resistors with a 2 % reference accuracy.
This IPOD , MP3 device charger circuit require an input voltage from 9 to 15 volts DC .
Modify the VR1 variable resistor you can adjust the output voltage at 5 volts .
The L1 coil has 75 turns of 0.5 mm enameled copper wire on a Neosid powdered iron core 17-732-22 .

UC3842 CURRENTMODE PWM CONTROLLER

This supply uses an SGS-Thomson UC3842 IC in an off-line flyback regulator, providing + 5 V at 4 A and ± 12 V at 300 mA. This enables a small high-frequency (50 kHz) transformer, to handle large amounts of power that are normally handed by a 60-Hz transformer. Q1 is a 5-A 500-V MOSFET, and the diodes are fast-recovery types. T1 has a 45-turn primary winding of #26 wire. The 12-V windings are each 9 turns of #30 wire, bifilar wound. The 5-V winding is 4 turns of four bifilar #26 wires. The control (feed-back) winding is two bifilar, parallel10-turn, #30 windings. The core is Ferroxcube EC35-3C8 with a ³/₈" center leg.

TIMING CALCULATORS FOR LM555

Resistor values are in Ohms (1K = 1000) - Capacitor values are in Microfarads (1uF = 1)

  NOTE: The leakage currents of electrolytic capacitors will affect the actual output results of the timers. To compensate for leakage it is often better to use a higher value capacitor and lower value resistors in the timer circuits.

LM555 Monostable Oscillator Circuit Diagram

The digital voltmeter ICL7107CPL

Here is my lovingly-crafted schematic for the voltmeter module. Note that this could be made as a standalone voltmeter, it will measure up to 20v DC. In our finished product, the +5V will be sourced from an LM78L05 voltage regulator.

And the parts list:

    IC1 – Intersil ICL7107CPLZ
    IC2 – Intersil ICL7660
    D1~D3 – 1N4148 diodes
    LED displays – Agilent HDSP521G 2 x 7-segment green displays (common anode). You can use anything really, as long as it is common anode, and each segment is ~8mA
    R1 – 220 ohm – all resistors 0.25W
    R2 – 10k ohm
    R3 – 1M ohm
    R4 – 47k ohm
    R5 – 15k ohm
    R6 – 100k ohm
    R7 – 1k ohm multiturn potentiometer/trimpot (for calibration)
    C1 – 10nF – all capacitors must be rated for at least 25V
    C2 – 20nF
    C3 – 470 nF
    C4 – 100 nF
    C5 – 100 pF
    C6,7 – 10 uF electrolytic

Please note that this is a work in progress and errors may have been made, or values altered at any time after publication.

An Arduino Compatible - CP2102

Standard Arduino boards use FTDI’s FT232RL to interface with computer’s USB port. Since FT232R is just a USB to UART converter, it is possible to build an Arduino compatible USB interface using other USB to UART chips.

One such alternative is Silicon Labs‘ CP2102. I particularly like this USB to UART transceiver because very few extra components are required for it to work. As an added benefit, this chip is also cheaper than the ubiquitous FT232R. Of course, there are also a few trade offs. First of all, CP2102 does not provide a bit bang interface (the X3 pins on the Arduino board on the other hand can be used for bit bang operations, but the X3 pins are not soldered with header pins by default and thus for the average users no bit bang support should not be an issue). Secondly, CP2102 does not have the configurable general purpose I/O pins to drive the TX/RX LEDs. There are other minor differences as well (for instance the maximum transmission speed for FT232R is 3Mbps while CP2102 tops at 1Mbps. Both chips are more than adequate for the maximum 115,200 baud rate supported in Arduino environment), but they do not affect the performance in our application of interfacing with Arduino.

Here is the schematics for using CP2102 with ATmega328p (the circuit below is compatible with the Arduino IDE):

if you compare the above circuit with the official Arduino Duemilanove board you will see that the interfacing portions (RXD, TXD and TDR) are virtually identical.
Since CP2102 comes only in QFN-28 packaging, some people might find it slightly harder to deal with than TSSOP. Using the prototyping method I mentioned a few months back though, it is fairly straightforward to use the chip on a standard perf-board nevertheless. No special tools or stencils are needed. The following picture shows the USB to UART converter portion of the Arduino, which can be used to replace the FT232 break out board. I chose to break out the converter so that I could use it in other projects that require serial connections.



If you are running Linux, you do not need any third-party device drivers. All recent Linux kernels support CP210x via the usbserial kernel module. Once connected, you should be able to use dmesg and see these messages:

    [ 8333.572512] usb 8-2: new full speed USB device using uhci_hcd and address 3
    [ 8333.744748] usb 8-2: configuration #1 chosen from 1 choice
    [ 8333.785114] usbcore: registered new interface driver usbserial
    [ 8333.785161] USB Serial support registered for generic
    [ 8333.785221] usbcore: registered new interface driver usbserial_generic
    [ 8333.785222] usbserial: USB Serial Driver core
    [ 8333.792419] USB Serial support registered for cp210x
    [ 8333.792460] cp210x 8-2:1.0: cp210x converter detected
    [ 8333.920011] usb 8-2: reset full speed USB device using uhci_hcd and address 3
    [ 8334.076745] usb 8-2: cp210x converter now attached to ttyUSB0
    [ 8334.076760] usbcore: registered new interface driver cp210x
    [ 8334.076762] cp210x: v0.09:Silicon Labs CP210x RS232 serial adaptor driver

If you are running Windows, you will need to install the royalty-free driver from Silicon Labs directly.

Under Linux, CP210x shows up as a a ttyUSB device. You can use the Arduino IDE to program your ATmega328p’s just as you would with an official Arduino. Serial communication via the serial monitor works the same way as well. Like the official Arduino, the above circuit also automatically resets whenever you upload a program.
 

2N2907A Small Signal PNP Transistors

2N2907A

Small Signal PNP Transistors

This circuit shows a synchronous-rectifier-based ac/dc converter which has high accuracy up to about 2.5 MHz. To calibrate, apply a 1- to 2-MHz 1-V pp sine wave and adjust the delay compensation so that bridge switching occurs when the sine crosses zero. Next, adjust both skew compensation pots for minimum aberrations in the ac output signal. Finally, adjust the gain trim for a dc output that corresponds to the ac input.

Circuit diagram ATMEGA64 8-bit Microcontroller with 64K Bytes In-System Programmable Flash

The ATmega64 is a low-power CMOS 8-bit microcontroller based on the AVR enhanced RISC architecture. By executing powerful instructions in a single clock cycle, the ATmega64 achieves throughputs approaching 1 MIPS per MHz, allowing the system designer to optimize power consumption versus processing speed.

The AVR core combines a rich instruction set with 32 general purpose working registers. All the 32 registers are directly connected to the Arithmetic Logic Unit (ALU), allowing two independent registers to be accessed in one single instruction executed in one clock cycle. The resulting architecture is more code efficient while achieving throughputs up to ten times faster than conventional CISC microcontrollers.

TEA2025B bassed amplifier circuit and explanation

A very simple audio amplifier electronic project that can be used in small portable audio applications can be designed using the TEA2025B audio amplifier IC . This audio power amplifier project supports a wide input voltage range between 3 and 15 volts .
Input capacitor is PNP type allowing source to be referenced to ground.
In this way no input coupling capacitor is required. However, a series capacitor (0.22uF)to the input side can be useful in case of noise due to variable resistor contact.
The bootstrap connection allows to increase the output swing. The suggested value for the bootstrap capacitors (100μF) avoids a reduction of the output signal also at low frequencies and low supply voltages.
The voltage gain is determined by on-chip resistors R1 and R2 together with the external RfC1 series connected between pin 6 (11) and ground. The frequency response is given approximated Input capacitor is PNP type allowing source to be referenced to ground.
The frequency response is given approximated : VOUT/VIN= R1/(Rf +R2 +(1/JWC1))
The maximum output power that can be obtained using the TEA2025B audio amplifier in stereo mode is around 2.3 watts on a 4 ohms load .

Design on the basis of electrical home appliances liquid crystal display system MC9S08AW32 and HT1621

Drive the performance characteristic of the chip HTl621 and make up the structure, combine and fly to think of Karl’s little controller MC9S08AW32 according to the liquid crystal, have described the design of a kind of electrical home appliances liquid crystal display system. Have described HT1621 practical application in the display system design of this liquid crystal in detail, have explained hardware forming and software design process of this system especially, and provide interface block diagram of the hardware and software flow diagram. The display system of this liquid crystal reveals steadily, fine performance such as low power dissipation, the interface friendship, and saved little controller I/O port resources. 

The display system of the liquid crystal is the important component of the control system of electrical home appliances. The liquid crystal display system of electrical home appliances reveals the module Liquid Crys-tal Display through the liquid crystal Show important information such as its working state and time out, users assign the operation order to deal with to the little controller according to the information, thus realize the control on function of the electrical home appliances. The liquid crystal reveals the module not merely can reveal figure, Chinese character and character vividly, and the consumption is little, the working voltage is low, so the application in the modern electrical home appliances products is more and more extensive. The intersection of electrical home appliances and the intersection of liquid crystal and display system including liquid crystal reveals the module LCD mainly, backlight source, liquid crystal drive the chip HT1621, flies and thinks of Karl’s little controller MC9S08AW32 and button module etc.. Here, according to the performance characteristic, making up structure and programming method, combine MC9S08AW32 of HT1621, have described HT1621 practical application in the liquid crystal display system of electrical home appliances in detail, have explained hardware design and software design process of this system, and provide hardware interface block diagram and software flow diagram of this system.

A liquid crystal drives the chip HT1621 introduction

1. Characteristic of 1 HT1621

HTl621 is held group HOLTEK in Taiwan 128 sections which the company puts out 32* 4The multi-functional driver of the built-in memory, can drive the multistage LCD character to be its main characteristic. HTl621 can form LCD and reveal module and display system, only needs 3- 4 with the communication of little controller, it also included at the same time the electricity orders in a province, reduced the systematic consumption effectively. SSOP that HTl621 is 48 pins encapsulates, has a lot of fine characteristics, its main characteristic is as follows:

1.Working voltage 2. 4- 5. 2 V;
2.Inlay 256 kHz RC oscillator inside;
3.The order can be used in reducing the consumption economizing on electricity;
4.A LCD driver of 32* 4 sections;
5.32* 4 that inlay in one reveal RAM memory;
6.Mode of three kinds of access to data.

1. Systematic structure within 2 HT1621
The systematic structure includes revealing the memory RAM within HT1621 Systematic oscillator, guard the gate the intersection of dog and timer, the intersection of voice and generator and the intersection of LCD and driver,etc.. Only introduce the display memory correlated to this design RAM as follows With LCD driver.

1. 2. 1 reveals the memory RAM
The static behavior reveals the memory RAM, store the data revealed in the form of 32* 4. The data of RAM can shine upon the driver to LCD; The data stored in RAM can use READ, WRITE and READ-MODIFY-WRITE order to visit. Fig. 1 is the image from RAM to LCD driver.

1. 2. 2 LCD driver
HT1621 is one and 128 sections 32* 4LCD driver. It can dispose from software into LCD driver biasing and 2, 3 or 4 public ports of 1/ 2 or 1/ 3. This characteristic makes HT1621 suitable for many kinds of LcD to employ the occasion. LCD drives the clock to be produced from the frequency division of the systematic clock; LcD drives the frequency value of the clock to keep as 256 Hz, it is 32 by the frequency. The shaking brilliantly of 768 kHz, Rc oscillator or external clock in slice are produced; See Table 1 in relevant order of LcD driver.

Runic 100 is ” 100″ Express the order mode type. If carry out the continuous order, except the first order, mode type of other orders yard will be neglected. LCDOFF orders to make LCD bias the generator and fail, thus close LCD to reveal; LCD ON orders to make LCD bias the generator effectively, thus opened LCD to reveal.