User Interface - Lcd Driver Based On The HT1621 Controller

Application Note Abstract This Application Note describes implementation of a liquid crystal Display (LCD) driver based on the widely available HOLTEK HT1621 LCD Controller Methods and algorithms of Display control are described and an API library is provided. The LCD used in this example was a customer’s custom part. The proposed algorithms CAN be easily adapted to any custom LCD panel connected to the controller. Introduction LCDs are widely used as data Display devices in embedded systems. Among the features that have made LCDs popular are low price, low power dissipation, lightweight, durability, reliability, and broad support by dedicated ICs for Communication with Microcontrollers A good example of an LCD Driver is the Hitachi character LCD Driver HD44780, the industry standard. This dot-matrix LCD Controller is supported by PSoC APIs. It is useful in applications that permit alphanumeric data Display However, specialized Displays are often needed. Specialized Displays keep end- product prices low, simplify the Interface between the Microcontroller and LCD Driver and decrease weight and size parameters. Examples of specialized Displays include Clocks calculators, telephones, and home and industrial appliances. This implementation is based on one of these dedicated drivers, the HT1621. This Application Note addresses the proposed implementation in two parts: ƒ General Description ƒ LCD Driver Implementation General Description The HT1621 driver is a 128-segment (32x4), multi-functional LCD Driver with memory mapping. The software configuration feature of HT1621 makes it suitable for many LCD applications, including LCD modules and Display subsystems. Only three or four connections are required for interfacing between the host controller and the HT1621. A structural schematic of the Display system is shown in Figure 1. This structure requires few external components and uses only three Interface connections. The system consists of the PSoC, HT1621 controller, and an LCD panel. The HT1621 besides its primary function as an LCD controller, has peripherals including the watchdog Timer time base generator and the Tone frequency generator. For more information about these features, refer to the HT1621 data sheet. Note that the controller has an on-chip RC Oscillator (256 kHz) for controlling the LCD and peripherals. This General Description focuses on the components and functions of the HT1621 driver that relate directly to the LCD: ƒ Display Memory RAM ƒ LCD Driver in HT1621 ƒ Command Format ƒ Interfacing with HT1621

Big Motor Driver TLP250

I have posted a motor controller design that is supposed to be simple, robust, cost effective, and able to handle high currents.  Above is a schematic of the first part of the design.  I will post an updated version to include a PIC to accept commands from a PC, Microcontroller, etc. and provide the direction/PWM signals to the H-bridge.  I am still working on the PCB but here is what I have done so far for review/critism.  What is not shown in the schematic are the in-line fuses for protection.

For the PIC, I use MBasic and PicBasic Pro to write the code.  This should convert easly to the BS2 and PicAxe.


 I updated the schematic again.  As suggested I changed the MOSFET driver to a TLP250 and dropped the 1K resistor across the Gate to source.
Update the schematic to show that the logic grounds are isolated from the dirty motor grounds.

Finished the PCB design.  Once boards are complete will test and post schematic and board files once any kinks are worked out.

I got the prototype boards back from the manufacture two days after I sent them off.  As you'll see below, the quality is excellent.  Tonight I populated the board and checked out functionality with a multimeter prior to testing with a motor.  I managed to get everything put together right so on to the smoke check.  I hooked up a good size motor with a lot of torque and applied power.  The motor moved in both directions and the MOSFET did not even get warm.  This test was applying full power to the motor and not PWM.  Next, I'll write some code and test functionality with PWM hooked to my Oscope so I can check the signals and see how high I can take the frequency.  I'll get around to posting some video but, in the mean time, here are some pictures of one of the finished boards.

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.