Bq2004 and DV2004S1 EVM Question for some Resiter R1,R2,R3 Value

Hi

We thinking use BQ2004 for NiMH battery Charge.

But we have questio for some EVM Resiter Value Caliculate.

EVM DV2004S1  EVM Document , Page 4 , Bq2004S1 EVM Schematic.

【　Question　】

　　We want to know , how to caliculate  R1, R2, R3??

     Now we checking device data sheet , but we can not found about  these Resiter value caliculate.

    And we checked about other EVM with  same device Resister , but other EVM these Resiter value are differente.

    We guess, thise device Input Impedance is very high, and need thise High Value Resiter for them.

     For instnace , R1 => 510kohm , R2 => 510kohm ,,,,,, 

    Please tell me , how to caliculate about thise R1,R2,R3 Resister value , and  reason Why need  High

     value   Resister ??   

 Jasper