Texas Instruments Evaluation Board for the LM25066I LM25066I-EVM/NOPB LM25066I-EVM/NOPB 데이터 시트
제품 코드
LM25066I-EVM/NOPB
OUT
UVLO/EN
VIN
GATE
DIODE
ADR2
ADR1
ADR0
VDD
N/C
FB
OVLO
SDA
SCL
PGD
N/C
SENSE
VDD
SMBus
Interface
SMBA
CL
CB
RETRY
VAUX
VDD
VREF
TIMER
PWR
GND
LM25066I/A
Auxillary ADC Input
(0V - 1.16V)
(0V - 1.16V)
UVLO/EN
R
1
R
2
R
3
R
4
R
5
Q
2
V
OUT
C
LOAD
R
S
V
IN
C
VDD
C
VREF
R
PWR
C
T
C
IN
D
Z
Q
1
R
PG
OUT
SNVS824C – JUNE 2012 – REVISED MARCH 2013
FUNCTIONAL DESCRIPTION
The inline protection functionality of the LM25066I/A is designed to control the in-rush current to the load upon
insertion of a circuit card into a live backplane or other “hot” power source, thereby limiting the voltage sag on the
backplane’s supply voltage and the dV/dt of the voltage applied to the load. Effects on other circuits in the
system are minimized, preventing possible unintended resets. A controlled shutdown when the circuit card is
removed can also be implemented using the LM25066I/A.
insertion of a circuit card into a live backplane or other “hot” power source, thereby limiting the voltage sag on the
backplane’s supply voltage and the dV/dt of the voltage applied to the load. Effects on other circuits in the
system are minimized, preventing possible unintended resets. A controlled shutdown when the circuit card is
removed can also be implemented using the LM25066I/A.
In addition to a programmable current limit, the LM25066I/A monitors and limits the maximum power dissipation
in the series pass device to maintain operation within the device Safe Operating Area (SOA). Either current
limiting or power limiting for an extended period of time results in the shutdown of the series pass device. In this
event, the LM25066I/A can latch off or repetitively retry based on the hardware setting of the RETRY pin. Once
started, the number of retries can be set to none, 1, 2, 4, 8, 16, or infinite. The circuit breaker function quickly
switches off the series pass device upon detection of a severe over-current condition. Programmable under-
voltage lockout (UVLO) and over-voltage lockout (OVLO) circuits shut down the LM25066I/A when the system
input voltage is outside the desired operating range.
in the series pass device to maintain operation within the device Safe Operating Area (SOA). Either current
limiting or power limiting for an extended period of time results in the shutdown of the series pass device. In this
event, the LM25066I/A can latch off or repetitively retry based on the hardware setting of the RETRY pin. Once
started, the number of retries can be set to none, 1, 2, 4, 8, 16, or infinite. The circuit breaker function quickly
switches off the series pass device upon detection of a severe over-current condition. Programmable under-
voltage lockout (UVLO) and over-voltage lockout (OVLO) circuits shut down the LM25066I/A when the system
input voltage is outside the desired operating range.
The telemetry capability of the LM25066I/A provides intelligent monitoring of the input voltage, output voltage,
input current, input power, temperature, and an auxiliary input. The LM25066I/A also provides a peak capture of
the input power and programmable hardware averaging of the input voltage, current, power, and output voltage.
Warning thresholds which trigger the SMBA pin may be programmed for input and output voltage, current, power
and temperature via the PMBus interface. Additionally, the LM25066I/A is capable of detecting damage to the
external MOSFET, Q
input current, input power, temperature, and an auxiliary input. The LM25066I/A also provides a peak capture of
the input power and programmable hardware averaging of the input voltage, current, power, and output voltage.
Warning thresholds which trigger the SMBA pin may be programmed for input and output voltage, current, power
and temperature via the PMBus interface. Additionally, the LM25066I/A is capable of detecting damage to the
external MOSFET, Q
1
.
Figure 31. Typical Application Circuit
Power Up Sequence
The VIN operating range of the LM25066I/A is +2.9V to +17V, with transient capability to +24V. Referring to
and
, as the voltage at VIN initially increases, the external N-channel MOSFET (Q
1
) is held
off by an internal 190 mA pulldown current at the GATE pin. The strong pulldown current at the GATE pin
prevents an inadvertent turn-on as the MOSFET’s gate-to-drain (Miller) capacitance is charged. Additionally, the
TIMER pin is initially held at ground. When the V
prevents an inadvertent turn-on as the MOSFET’s gate-to-drain (Miller) capacitance is charged. Additionally, the
TIMER pin is initially held at ground. When the V
IN
voltage reaches the POR threshold, the insertion time begins.
During the insertion time, the capacitor at the TIMER pin (C
T
) is charged by a 5.5 µA current source and Q
1
is
held off by a 2 mA pulldown current at the GATE pin regardless of the input voltage. The insertion time delay
allows ringing and transients at VIN to settle before Q
allows ringing and transients at VIN to settle before Q
1
is enabled. The insertion time ends when the TIMER pin
14
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