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ISO5452: Current levels passing through GND2

Pol REYMOND
Intellectual 2070 points
Part Number: ISO5452
Other Parts Discussed in Thread: TL431

Hi team,

 

In order to size our insulated power supply for the ISO5452 +15V/-8V application, my customer would like to estimate current levels passing through GND2.

1-     Does the “IQ2 Output supply quiescent current 6 mA” flows through/to/from GND2 or rather directly from Vcc2 to Vee2?

 

2-     Do they have other currents that passes through GND2 than the blanking capacitor ones?

  1. “I(CHG) Blanking capacitor charge current 0.5 mA” (assuming that the blanking capacitor is connected to GND2 as Fig 50)
  2. “I(DCHG) Blanking capacitor discharge current 14 mA”

 

 

Do they have to consider other currents through GND2?

 

Thanking you in anticipation

Pol

 

PS

We’ve noticed that on fig 29 of the TL1431, the bipolar type should be a PNP rather than a NPN

  • 0
    TI__Intellectual 1665 points

    Hi Pol,

    There are a few circuits which are referenced to GND2 and would take some currents. The bias current of those circuits is less than 1mA. The discharge currnt of the blanking capacitor just lasts for short period of time over each PWM cycle that the averaged number is much less than 14mA. Reasonably small decoupling capacitors should be able to provide enough charge for circuits to operate while without much voltage ripple. Majority of the supply current flows through VCC2 and VEE2.  

    I think your comments on TL431 are correct. Could you please reach out to the responsible team to get it corrected? 

    With Regards,

    Xiong