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LM5026: LM5026 Vcc

Part Number: LM5026

Hi,

Modify the TIME resistor and connect it to REF (R16 NC, R10=100k ohm) as shown in the figure below. An abnormality of the VCC power supply occurs.

If R10 is changed to 33k ohm, the VCC is normal.

please help confirm

1. Are there upper and lower limits for the original resistance values of R10 and R16?
2. How does the resistance of REF to TIME (R10) affect VCC?
3. REF, TIME has a current limit or related requirements?

 

  • Hello Rock,

    The use of RSET (R16 in their circuit) depends on the type of active clamp used, P-channel or N-channel.  For a ground referenced P-channel clamp RSET should be connected to GND to control overlap time.  For a high-side N-channel clamp RSET should be connected to REF to control deadtime.  This is discussed in section 7.3.3 of the datasheet.  Figure 14 shows the two modes of operation.  The modes are not interchangeable.

    You must connect RSET depending on the clamp configuration.

    Regards,

    Eric