ADP1048 Analog Devices, ADP1048 Datasheet - Page 23

• Manufacturer Part Number: ADP1048
• Description: Digital Power Factor Correction Controller with accurate AC Power Metering
• Manufacturer: Analog Devices

Data Sheet
Missing AC Line Cycles
Figure 22 shows examples of the typical missing ac line cycles
fault. The VIN_LOW flag is set when the instantaneous voltage
is below VIN_OFF for more than a quarter or half line cycle
(depending on how it is programmed). This flag can be used as
an early warning to the system via the AC_OK pin when more
than a half cycle is missing. The BROWN_OUT flag is also set;
this flag does not cause a shutdown.
If any other flag that is programmed for shut down is set (in this
example, VOUT_UV_FAULT), the power supply shuts down,
the INRUSH pin is asserted, and the controller prepares for the
next soft start cycle.
If the BROWN_OUT flag is cleared before VOUT drops below
the VOUT_UV_FAULT_LIMIT value (Register 0x44), opera-
tion resumes in normal mode (or fast loop mode if enabled);
otherwise, if VOUT drops below VOUT_UV_FAULT_LIMIT,
the INRUSH pin is reset and a new soft start cycle is started.
BROWN_OUT FLAG
(REG 0xFE80[2])
VIN_LOW FLAG
(REG 0x7C[3])
INRUSH PIN
Figure 23. Brownout Timing Diagram (VIN_UV_FAULT_RESPONSE Register Programmed to Shut Down After a One-Cycle Debounce)
(1 CYCLE DEBOUNCE)
VIN_UV_FAULT_LIMIT
VIN_UV_FAULT FLAG
BROWN_OUT FLAG
VIN_ON (REG 0x35)
VOUT
(REG 0xFE80[2])
VAC
INRUSH PIN
(REG 0x59)
VAC
Figure 22. Line Fault (Missing Cycles) Timing Diagram
VOUT_UV_FAULT_LIMIT
Rev. 0 | Page 23 of 84
(REG 0x44)
PSON Delay
The PSON start delay is programmable using Register 0xFE06,
Bits[3:2]. Four options are available: 0 ms, 50 ms, 250 ms, and
1000 ms.
Brownout Conditions
Brownout is another typical line fault condition in which the
line drops below the minimum specified operating level. This
level can be set with VIN_UV_FAULT_LIMIT (Register 0x59).
This flag can be programmed according to the standard PMBus
flag response. For example, it can be programmed to shut down
and restart after a certain delay.
During brownout, there are other conditions that can occur,
such as input overcurrent or output undervoltage. Each of these
faults can be programmed to shut down or disable the output,
based on the response action.
INRUSH DELAY TIME
SHUTDOWN
(REG 0xFE2E[2:0])
SOFT START TIME
(REG 0xFE2D[2:0])
ADP1047/ADP1048
VIN_ON (REG 0x35)
VIN_OFF (REG 0x36)