ADM1041-EVAL Analog Devices Inc, ADM1041-EVAL Datasheet - Page 20

• Manufacturer Part Number: ADM1041-EVAL
• Description: BOARD EVALUATION ADM1041
• Manufacturer: Analog Devices Inc

Specifications of ADM1041-EVAL

• Main Purpose: AC/DC, Secondary Side
• Outputs And Type: 1, Non-Isolated
• Power - Output: 24W
• Voltage - Output: 12V
• Current - Output: 2A
• Voltage - Input: 85 ~ 132VAC
• Board Type: Fully Populated
• Utilized Ic / Part: ADM1041
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Frequency - Switching: -
• Regulator Topology: -
• Lead Free Status / Rohs Status: Not Compliant

ADM1041
DIFFERENTIAL REMOTE SENSE AMPLIFIER
This amplifier senses the load voltage and is the main voltage
feedback input. A differential input is used to compensate for
the voltage drop on the negative output cable of the power
supply. An external voltage divider should be designed to set the
V
gain is 1.0. See Figure 9.
SET LOAD VOLTAGE
The load voltage may be trimmed via the SMBus by a trim stage
at the output of the differential remote sense amplifier. The
voltage at the output of the trimmer is 1.50 V when the voltage
loop is closed. See Figure 9.
LOAD OVERVOLTAGE (OV)
A comparator at the output of the load voltage trim stage
detects load overvoltage. The load OV threshold can be
trimmed via the SMBus. The main purpose is to turn off the
OrFET when the load voltage rises to an intermediate over-
voltage level that is below the local OVP level. This circuit is not
latching. See Figure 9.
LOCAL VOLTAGE SENSE
This amplifier senses the output voltage of the power supply just
before the OrFET. Its input is derived from one of the pins used
for current sensing and is set to 2.0 V by an external voltage
divider. The amplifier gain is 1.3. See Figure 9.
S
+ pin to approximately 2.0 V with respect to V
REMOTE
SENSE
FROM
LOAD
V
V
V
LS
S
S
+
–
21
20
2
NOTE:
ALL POTENTIOMETERS (
×1.3
35kΩ
35kΩ
SET UV CLAMP
THRESHOLD
THRESHOLD
SET LOAD
35kΩ
35kΩ
VOLTAGE
SET OVP
THRESHOLD
) ARE DIGITALLY PROGRAMMABLE THROUGH REGISTERS.
SET UVP
S
Figure 9. Block Diagram of Voltage Sense Amplifier
–. The amplifier
OVERVOLTAGE
SET LOAD
FALSE UV
1.5V
CLAMP
Rev. A | Page 20 of 64
1.25V
25kΩ
LOCAL OVERVOLTAGE PROTECTION (OVP)
This is the main overvoltage detection for the power supply. It is
detected locally so that only the faulty power supply shuts down
in the event of an OVP condition in an N+1 redundant power
system. This occurs only after a load OV event. The local OVP
threshold may be trimmed via the SMBus. See Figure 9.
LOCAL UNDERVOLTAGE PROTECTION (UVP)
This is the main undervoltage detection for the power supply. It
is also detected locally so that a faulty power supply can be
detected in an N+1 redundant power system. The local UVP
threshold may be trimmed via the SMBus. See Figure 9.
FALSE UV CLAMP
If a faulty power supply causes an OVP condition on the system
bus, the control loops in the good power supplies is driven to
zero output. Therefore, a means is required to prevent the good
power supplies from indicating an undervoltage, and they must
recover quickly after the faulty power supply has shut down.
The false UV clamp achieves this by clamping the output voltage
just above the local UVP threshold. It may be trimmed via the
SMBus. The OCPF signal disables the clamp during overcurrent
faults. See Figure 9.
DIFF. VOLTAGE SENSE
LOADVOK
OVP
UVP
CURRENT SHARE
CURRENT LIMIT
OCPF
TO
GENERAL
LOGIC
TO
GENERAL
LOGIC
CAPTURE
1V
V
1.5V
REF
3V
RAMP UP
70µA
START
SOFT-
ERROR AMP
VOLTAGE
5
V
CMP