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A question about ECCP dead band time setting

 
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lokken



Joined: 21 Feb 2010
Posts: 17

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A question about ECCP dead band time setting
PostPosted: Sat Jul 31, 2010 12:38 am     Reply with quote
I have used these codes for setting dead band time which is located at:
http://www.ccsinfo.com/forum/viewtopic.php?t=40040
Code:

#include <16F684.h>
#fuses XT,NOWDT,BROWNOUT,PUT
#use delay (clock=4000000)

void set_pwm_dead_band(int8 value)
{
int8 temp;
#byte PWM1CON = 0x16

// Put 'value' into the lower 7 bits of PWM1CON
// but don't change the top bit of PWM1CON.
value &= 0x7F;     
temp = PWM1CON; 
temp &= 0x80;   
temp |= value; 
PWM1CON = temp;
}

//=================================
void main()
{
setup_ccp1(CCP_PWM_FULL_BRIDGE  | CCP_PWM_H_H);

set_pwm_dead_band(0x1F);


// Put other PWM setup code here.


while(1);
}

But I couldn't set dead band time. How can I use these code for setting dead band time delay?
PCM programmer



Joined: 06 Sep 2003
Posts: 21708

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PostPosted: Sat Jul 31, 2010 10:53 am     Reply with quote
Quote:

I have used these codes for setting dead band time which is located at:
http://www.ccsinfo.com/forum/viewtopic.php?t=40040

Did you read the whole thread ? Read Ttelmah's comment at the end
of the thread.
lokken



Joined: 21 Feb 2010
Posts: 17

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PostPosted: Tue Aug 03, 2010 12:23 am     Reply with quote
OK I understand what you mean. But I have one more question, by your leave. Is it more reliable to drive H-Bridge with an external hardware like L298? Because if we couldn't set dead band, the mosfets or others can be burnt out because of their delay time. Is it true?
PCM programmer



Joined: 06 Sep 2003
Posts: 21708

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PostPosted: Tue Aug 03, 2010 12:32 pm     Reply with quote
I have used the LMD18200, which is an H-Bridge controller chip.
It contains the driver transistors in the package. It generates the
dead band time. (They refer to it as "no shoot-through current".)

Data sheet and appnote:
http://www.national.com/ds/LM/LMD18200.pdf
http://www.national.com/an/AN/AN-694.pdf

CCS program for the LMD18200:
http://www.ccsinfo.com/forum/viewtopic.php?t=40467
lokken



Joined: 21 Feb 2010
Posts: 17

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PostPosted: Wed Aug 04, 2010 12:27 am     Reply with quote
Ok Thanks for your considering...
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