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參數資料
| 型號： | NCP1337DR2G |
| 廠商： | ON SEMICONDUCTOR |
| 元件分類： | 穩壓器 |
| 英文描述： | PWM Current−Mode Controller for Free Running Quasi−Resonant Operation |
| 中文描述： | 0.5 A SWITCHING CONTROLLER, 130 kHz SWITCHING FREQ-MAX, PDSO7 |
| 封裝： | LEAD FREE, SOIC-7 |
| 文件頁數： | 12/14頁 |
| 文件大小： | 148K |
| 代理商： | NCP1337DR2G |
NCP1337
http://onsemi.com
12
The input information is the current injected in FB pin by
the feedback loop. The range of current is from 40 A for
overload detection to 220 A corresponding to V
CSrippleIN
.
In transients, currents from 0 to more than 400 A may also
appear: the circuitry is able to sustain them.
To regulate the FB pin voltage, the operational amplifier
needs to have a high gain and a wide bandwidth. But the
feedback information used internally needs to be filtered,
because we don’t want the controller to be sensitive to the
switching noise. For this purpose, a 20 kHz filter is added
after the shunt regulator, and any reading of the feedback
signal (for ripple mode, fault detection, or setpoint
elaboration) is done after.
Soft Burst Mode (Protection Mode)
The NCP1337 features a fault timer to detect an overload
completely independently of the V
CC
voltage. As soon as
the feedback loop asks for the maximum power, a fault is
detected, and an internal timer is started. When the fault
disappears the timer is reset, but if the timer reaches 80 ms,
the protection mode is activated.
Once this protection is toggled, output pulses are stopped
and DSS is deactivated (HV current source turnon
threshold changes from VCC
MIN
to VCC
LATCH
). V
CC
slowly decreases (the current consumption is ICC3), and
the HV current source is switched ON when V
CC
reaches
VCC
LATCH
. As a result V
CC
increases until VCC
ON
, but the
controller does not start as the output is still forced low.
V
CC
decreases again down to VCC
LATCH
, and a new
startup cycle occurs. On the second attempt, the output is
released, and NCP1337 effectively starts, with the
softstart activated. Figure 4 illustrates this behavior.
Safety Features
The NCP1337 includes several safety features to help the
power supply designer to build a rugged design:
OVP (Overvoltage on V
CC
): Activated when voltage
on pin V
CC
is higher than 18.6 V
BrownOut (Undervoltage lockout on bulk voltage):
Activated when voltage on pin BO is below 500 mV
Disable (Comparator activated by an external signal):
Activated when the voltage on BO pin is higher than
3.0 V but below 5.0 V
TSD (Temperature shutdown): Typically activated
when the die temperature is above 150
°
C, released at
120
°
C
All these events have the same consequence for the
controller: the DRV pulses are stopped. When the condition
disappears, the controller restarts with the softstart
activated.
Permanent Latch (Comparator activated by an external
signal): Activated when the voltage on BO pin is
above 5.0 V
When this comparator is activated, the DRV pulses are
stopped, and the DSS is deactivated (only the startup
current source is turned on each time V
CC
reaches
VCC
LATCH
, maintaining V
CC
between 5.0 V and 12 V):
the controller stays in this position until the V
CC
voltage is
decreased below 4.0 V, i.e., when the power supply is
unplugged from the mains (in normal operation, as soon as
a voltage is present on the HV pin, V
CC
is always kept
above 5.0 V).
Soft Ripple Mode
The soft ripple mode is a skip mode with a large
hysteresis on the skip comparator in order to ensure a
noisefree and highefficiency operation in lowload
conditions (standby). When internal setpoint is reaching
V
CSrippleIN
= 100 mV (corresponding to 20% of the
maximum setpoint), the output pulses are stopped. Then
FB loop asks for more power and internal setpoint is
increasing: when it reaches V
CSrippleOUT
= 130 mV
(corresponding to 25% of the maximum setpoint), the
output starts pulsing again. Softstart is activated in each
activity following a stop period. See Figure 5 for detailed
timing diagram.
HV Current Source
NCP1337 features a DSS, to allow operation without any
auxiliary voltage. But to protect the die in case of
shortcircuit on V
CC
pin, the current delivered by the HV
current source is lowered when V
CC
voltage is below 1.5 V.
In the case the current consumed on the DRV pin is
higher than the DSS capability (high Qg MOSFET or
failure), the HV current source is switched ON when V
CC
reaches VCC
MIN
, but the voltage on V
CC
pin keep on
decreasing. If there is no UVLO threshold to stop the DRV
pulses, the gate voltage will become too low and the risk is
high to destroy the MOSFET. NCP1337 features an
additional comparator, which threshold is 9.0 V: when V
CC
reaches this level whereas the HV current source is ON,
DRV pulses are stopped and the protection mode is
activated.
BrownOut
The brownout protection comparator has a fixed
reference of 500 mV. When the comparator is activated
(i.e., when the input voltage V
IN
is above the starting level),
a 10
A internal current source is activated and creates an
offset across the bottom resistor of the external resistor
divider. It gives the minimum hysteresis of the brownout
protection. By adding a series resistor between the divider
and the BO pin, it is possible to adjust (increase) the
hysteresis.
The BO pin also features two additional comparators: the
first one (that toggles at 3.0 V) stops the DRV pulses,
whereas the second one (that toggles at 5.0 V) permanently
latches off the controller (the V
CC
should be forced below
4.0 V to release the latch).
Figure 8 gives the internal implementation of the BO
pin.
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相關代理商/技術參數 |
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|---|---|
| NCP1337PG | 功能描述:電流型 PWM 控制器 PWM CONTROLLER RoHS:否 制造商:Texas Instruments 開關頻率:27 KHz 上升時間: 下降時間: 工作電源電壓:6 V to 15 V 工作電源電流:1.5 mA 輸出端數量:1 最大工作溫度:+ 105 C 安裝風格:SMD/SMT 封裝 / 箱體:TSSOP-14 |
| NCP1338 | 制造商:ONSEMI 制造商全稱:ON Semiconductor 功能描述:PWM Current-Mode Controller for Free Running Quasi-Resonant Operation |
| NCP1338DR2G | 功能描述:電流型 PWM 控制器 PWM CNTRL SOIC 8 RoHS:否 制造商:Texas Instruments 開關頻率:27 KHz 上升時間: 下降時間: 工作電源電壓:6 V to 15 V 工作電源電流:1.5 mA 輸出端數量:1 最大工作溫度:+ 105 C 安裝風格:SMD/SMT 封裝 / 箱體:TSSOP-14 |
| NCP1338PG | 制造商:ONSEMI 制造商全稱:ON Semiconductor 功能描述:PWM Current-Mode Controller for Free Running Quasi-Resonant Operation |
| NCP1351 | 制造商:ONSEMI 制造商全稱:ON Semiconductor 功能描述:Power Factor Controllers |
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