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TINA/Spice/NE555: NE555

Swetha Revanna
Prodigy 50 points
Part Number: NE555
Other Parts Discussed in Thread: TINA-TI, , TL494

Tool/software: TINA-TI or Spice Models

Dear Sir/Madam, 

I am designing a PWM generator using a NE555 timer in order to drive Half Bridge (which has both high side and low side switching). I have designed a circuit which gives non-inverting PWM signal using NE555 and I have added the common-emitter to get the inverted PWM to drive low side switch.

I am facing an issue, how this non-inverting PWM signal is used to drive the high side switch with differential potential and I went through some of the analog design circuits for half bridge driver but failed to understand.

Specifications:

  • The input to the NE555 timer is 5V (TTL)
  • The input to the half-bridge circuit is 15V 

I request an expert to answer my question

Thank you in advance, 

Swetha Revanna 

  • 0
    TI__Mastermind 35985 points
    Swetha,
    Since your questions have to do with design and not models, your inquiry has been moved to the Clocks & Timing Forum.
    The product experts who monitor this forum will be the best source of help.
    John
  • 0
    TI__Guru**** 152756 points
    Swetha,

    The trigger and threshold inputs are comparator inputs with the the other comparator inputs based on the voltage at the COMP pin. See section 8.2 of data sheet. Is your PWM similar to section 9.2.2 of the data sheet? The clock must a have a high duty cycle to perform well.

    What is the desired frequency of the PWM and the maximum and minimum duty cycle?

    If you need some dead time between the H driver's low driver and high driver considered using the TL494 instead.