PM9105AFE datasheet(5/10 Pages) SAMES

5 / 10 page

PM9105AF

sames

5/10

The values of these resistors should be calculated as follows:

Phase 1:

8 = R9 = (IL1/16µA) x R18/2

Phase 2:

10 = R11 = (IL2/16µA) x R19/2

Phase 3:

12 = R13 = (IL3/16µA) x R20/2

Where I

Secondary CT current at rated conditions.

18, R19 and R20

Termination resistors of the three current transformers.

1 + R1A, R4 and R15 set the current for the phase 1 voltage sense input. R2 + R2A,

5 + P5 and R16 set the current for phase 2 and R3 + R3A, R6 + P6 and R17 set the current

for Phase 3. The values should be selected so that the input currents into the voltage

sense inputs (virtual ground) is set to 14

µA at nominal line voltage. Capacitors C1,

C2 and C3 are for decoupling and phase compensation.

14 + P14 defines all on-chip bias and reference currents.

With R

14 + P14 = 24kΩ,

optimum conditions are set. P

14 may be varied within ± 10% for calibration purposes.

Any changes to R

14 will affect the output quadratically (i.e:

∆R = +5%, ∆FOUT =

+10%).

XTAL is a colour burst TV crystal (f = 3.5795 MHz) for the oscillator. The oscillator

frequency is divided down to 1.7897 MHz on-chip to supply the digital circuitry and

the A/D converters.

PM9105AFE 데이터시트(PDF) 5 Page - Sames