HR1211 circuit question for CR

AC-DC Power Converters
1

Hi MPSer,

As I know the Cr1&Cr2 are use to monitor Cr voltage make sure maximum output power watt and maximum on time.
May I know the Rc1 & Rc2 function on CR pin? if bad design can affect what’s part?

hr1211 with cr pin question
hr1211 with cr pin question966×600 31.5 KB

3

Dear Sir,

thank you very much!
as I know the R1 and C1 are high frequency filter for CSHB pin. so, the Cr2 and Rc2 are same? Can place same CSHB circuit location for CR pin use?

未命名

4

Hello John.Du,

I apologize, I misread your question. The CR pin takes the divided voltage of CR2, the resonant capacitor. The divided voltage is used to find the LLC switching frequency. If the input voltage to the CR pin is over, it may cause damage to the part. You can take a look at the EVB as a reference. EVHR1211-Y-00A

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Do not use the same circuit. The CSHB is current sensing for the half-bridge. The CR is for voltage sensing on the LLC resonant capacitor.

Thank you,
Vinh Tran
Field Applications Engineer

5

Dear Sir,

Thank you for soft remind.
May I know MPS has CR design formula for Cr1/Cr2/Rc1/Rc2 and like as CSHB detail description?

6

Hello John.du,

Unfortunately, we do not have equations for the selection of those components.

Thank you,
Vinh Tran
Field Applications Engineer

7

Hello Sir I just need to know that if AC Supply is removed and what happens if X-capacitor is not discharged In HR1211 IC?