TPSF12C1-Q1: What is RPAR CPAR in TPSF12CX-DESIGN-CALC

Yee Wilson

Part Number: TPSF12C1-Q1

In TPSF12Cx quickstart calculator Rev A2.xlsm, what's the definition of RPAR and CPAR in CM choke model. Could you draw the equivalent model to let me know the location of RPAR and CPAR?

11 months ago

0 Timothy Hegarty 11 months ago

TI__Guru 50937 points

Hi Yee,

Cpar is the effective parasitic capacitance from the switch node to chassis ground, and Rpar is the associated series resistance. Cpar is the critical parameter here as it sets the amplitude of the common-mode (CM) current for a given dv/dt of the switch voltage. 100pF is a typical value.

Regards,

Tim

0 Yee Wilson 11 months ago in reply to Timothy Hegarty

Prodigy 30 points

I means the RPAR and CPAR in red box.

0 Timothy Hegarty 11 months ago in reply to Yee Wilson

TI__Guru 50937 points

Hi Yee,

That’s the CM choke parasitic capacitance and parasitic resistance. The impedance vs. frequency curve enables derivation of these parameters (Rpar is the peak impedance at resonance and Cpar sets the resonant frequency with Lcm).

Regards,

Tim

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TPSF12C1-Q1: What is RPAR CPAR in TPSF12CX-DESIGN-CALC