ADP1048WARQZ-R7 datasheet(20/82 Pages) AD

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ADP1048W

Data Sheet

LINE FAULT PROTECTIONS AND SOFT START SEQUENCING

PSON OPERATION

To comply with PMBus standards, the PFC circuit controlled

by the ADP1048W can be turned on and off by the hardware

PSON pin and/or the software PSON command. The setting of

Bit 2 in Register 0x02 determines whether the PSON pin and/or

the PSON command is used. If the PSON pin is used, the pin can

be configured to be either active high or active low (see Table 18).

AC LINE DETECTION

The ADP1048W is capable of detecting several parameters of

the ac line input voltage and taking the appropriate program-

med actions when necessary. The detection is a combination of

time and voltage measurements and is implemented via the

VAC pin, which detects the rectified ac input voltage. This

allows early detection of ac line faults and early warning for

the host system, thereby increasing reliability.

Five main parameters are related to ac line detection.

•

VAC_LINE_PERIOD (Register 0xFE85)

•

VAC_THRESHOLD_SET (Register 0xFE25)

•

VAC_THRESHOLD_READ (Register 0xFE26)

•

MIN_AC_PERIOD_SET (Register 0xFE27)

•

MAX_AC_PERIOD_SET (Register 0xFE28)

AC Line Period and Zero Crossing

The input ac line period is measured every half period of the ac

line cycle and is reported in the VAC_LINE_PERIOD register

(Register 0xFE85).

During the first 40 ms, the ac line period is measured between

two consecutive falling crossings of the threshold value, which

is set in the VAC_THRESHOLD_SET register (Register 0xFE25,

Bits[6:0]). The ac line period is then measured between two

consecutive falling crossings and compared to the average value

of the input line voltage, which is calculated during each half line

period. The VAC average reading can be found in the VAC_

THRESHOLD_READ register (Register 0xFE26, Bits[6:0]).

If the measured period is larger than MAX_AC_PERIOD_SET

or smaller than MIN_AC_PERIOD_SET, the default, MAX_AC_

PERIOD_SET, is used as the value of the period.

As shown in Figure 14, the two consecutive crossing points,

B and C, are used to determine the zero-crossing point of the

ac line. The middle point between B and C is calculated as the

zero-crossing point.

This information is used by the control loop, as well as the

power metering block.

Figure 14. AC Line Period Detection

VAC AVERAGE

(REG 0xFE26)

VAC

THRESHOLD

(REG 0xFE25)

HALF AC

LINE PERIOD

Rev. 0 | Page 20 of 82

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