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UCC28070-Q1: Current sense measurement

Mame TINE
Intellectual 305 points
Part Number: UCC28070-Q1

Hi,

I wish use your product in a 3.6 kW PFC with an switching frequency of 300 kHz. for current measurement i like an Hall sensor type melexis MLX91210 but the time response of this sensor is 5µs or the period of cutting current is 3.3 µs therefore this time response of the sensor is higher than the period. My question is to know if the difference can cause error on current measurement. 

i have 3 choice for current measurement : current transformer, Hall sensor or shunt resistor but don't know which of these solution is better can you give me some advice for selection.

when i use shunt resistor or hall sensor can sense the current flowing into inductor and disable the RSYNTH pin?

Can you give some supplies of current transformer?

  • 0
    TI__Mastermind 34465 points
    Hello Mame TINE
    As you discovered the Hall effect current sensor is very slow and is unsuitable for sensing current when you have a switching period of only 3.3uS.
    It is also an expensive part and requires a bipolar power supply to operate. It really has no advantages in sensing high frequency switching currents.
    You can use a current transformer or a shunt resistor in series with the boost MOSFET at 300kHz.
    The RSYNTH function means that you do not need to use another current transformer to sense the boost diode current. But of course you can also disable the RSYNTH and use an extra current transformer if you so desire.
    Regards
    John