PWM drives- sets my pulse high !

[dreamproject]

Hi all,

I am planning to use an LM629 to drive a DC motor . Data sheets . Since this IC is to cost me 40 $ , I would appreciate if you could clear up some doubts before I invest so must money. Application example figure 16 , page 23 shows a typical PWM circuit . Can this circuit be used for any DC motor voltage / rating [automobile wiper motor] . Are any modifications necessary.

0. I am not able to understand the instructions (number of inputs) required for motor control .

1. Suppose my input was through a pot, where must this data be input ?

2. My pot's centre voltage (~2.5v) , must provide no deflection of the motor shaft . Moving the pot to the left or right moves the shaft propotionately either direction . (Must the computer process the input to provide the output data ?)

3. If I am to interface this IC to a PC's parallel port , are the number of data lines sufficient ?

4. Can the circuit be modified for continuous monitoring (with minimal inputs from PC) ? ,i.e tying CS,RD - to respective voltage levels.

5. Is this a programmable IC ? (I do not understand the instruction set part, Are these input through the data lines ?)

6 . Beyond the PWM output stage , what other circuits are required to drive a DC motor? (If I'm not able to acquire LM18298 IC)

7. Will this work with home-made encoders ?. (tips on how to make one -please )

8. Can an intermediate IC (between PC and the LM629) be used to buffer / generate outputs and inputs , possibly a micro-controller (any suggestions ?)

9. Any ideas / circuits to the above effect would be accepted with immense gratitude ,

Thanks

 

[audioguru]

Hi Dream,
That's a very complex IC just to control a motor. I think you will get more high pulses when you are writing its computer program.
1) and 2) Your input pot must be translated by an A to D converter to be read by your computer.
6) The LM18298 full-bridge driver IC is discontinued (obsolete), usually operates with a 42V supply, delivers only 2A output and has a max output voltage loss of 4.9V. Search Google for an H-bridge circuit or IC that meets your motor's requirements.
7) The encremental encoder is a mechanical or optical thingy with quadrature and pulse outputs. Will you DIY?

 

[dreamproject]

oh my

Oh my Gosh , I just purchased it for 35$-(1850 INR) , Am i dead , Is it not possible to make an encoder. Please do help .

Thanks