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參數(shù)資料
| 型號(hào)： | TOP247F |
| 英文描述： | SMPS Controller |
| 中文描述： | 開關(guān)電源控制器 |
| 文件頁數(shù)： | 9/52頁 |
| 文件大?。?/td> | 457K |
| 代理商： | TOP247F |
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TOP242-250
9
H
9/02
prevent transformer saturation due to large load transients in
forward converter applications. DC
of 38% at the OV thresh-
old was chosen to ensure that the power capability of the
TOPSwitch-GX
is not restricted by this feature under normal
operation.
Remote ON/OFF and Synchronization
TOPSwitch-GX
can be turned on or off by controlling the current
into the LINE-SENSE pin or out from the EXTERNAL
CURRENT LIMIT pin (Y, R or F package) and into or out from
the MULTI-FUNCTION pin (P or G package) (see Figure 11).
In addition, the LINE-SENSE pin has a 1 V threshold compara-
tor connected at its input. This voltage threshold can also be used
to perform remote ON/OFF control. This allows easy implemen-
tation of remote ON/OFF control of
TOPSwitch-GX
in several
different ways. A transistor or an optocoupler output connected
between the EXTERNAL CURRENT LIMIT or LINE-SENSE
pins (Y, R or F package) or the MULTI-FUNCTION pin (P or G
package) and the SOURCE pin implements this function with
“active-on” (Figures 22, 29 and 36) while a transistor or an
optocoupler output connected between the LINE-SENSE pin
(Y, R or F package) or the MULTI-FUNCTION (P or G package)
pin and the CONTROL pin implements the function with
“active-off” (Figures 23 and 37).
When a signal is received at the LINE-SENSE pin or the
EXTERNAL CURRENT LIMIT pin (Y, R or F package) or
the MULTI-FUNCTION pin (P or G package) to disable the
output through any of the pin functions such as OV, UV and
remote ON/OFF,
TOPSwitch-GX
always completes its current
switching cycle, as illustrated in Figure 10, before the output is
forced off. The internal oscillator is stopped slightly before the
end of the current cycle and stays there as long as the disable
signal exists. When the signal at the above pins changes state
from disable to enable, the internal oscillator starts the next
switching cycle. This approach allows the use of these pins to
synchronize
TOPSwitch-GX
to any external signal with a
frequency between its internal switching frequency and 20 kHz.
As seen above, the remote ON/OFF feature allows the
TOPSwitch-GX
to be turned on and off instantly, on a cycle-
by-cycle basis, with very little delay. However, remote
ON/OFF can also be used as a standby or power switch to turn
off the
TOPSwitch-GX
and keep it in a very low power
consumption state for indefinitely long periods. If the
TOPSwitch-GX
is held in remote off state for long enough time
to allow the CONTROL pin to dishcharge to the internal
supply under-voltage threshold of 4.8 V (approximately 32 ms
for a 47
μ
F CONTROL pin capacitance), the CONTROL pin
goes into the hysteretic mode of regulation. In this mode, the
CONTROL pin goes through alternate charge and discharge
cycles between 4.8 V and 5.8 V (see CONTROL pin operation
section above) and runs entirely off the high voltage DC input,
but with very low power consumption (160 mW typical at
230 VAC with M or X pins open). When the
TOPSwitch-GX
is
remotely turned on after entering this mode, it will initiate a
normal start-up sequence with soft-start the next time the
CONTROL pin reaches 5.8 V. In the worst case, the delay from
remote on to start-up can be equal to the full discharge/charge
cycle time of the CONTROL pin, which is approximately
125 ms for a 47
μ
F CONTROL pin capacitor. This
reduced consumption remote off mode can eliminate
expensive and unreliable in-line mechanical switches. It also
allows for microprocessor controlled turn-on and turn-off
sequences that may be required in certain applications such as
inkjet and laser printers.
Soft-Start
Two on-chip soft-start functions are activated at start-up with
a duration of 10 ms (typical). Maximum duty cycle starts from
0% and linearly increases to the default maximum of 78% at
the end of the 10 ms duration and the current limit starts from
about 85% and linearly increases to 100% at the end of the
10ms duration. In addition to start-up, soft-start is also
activated at each restart attempt during auto-restart and when
restarting after being in hysteretic regulation of CONTROL
pin voltage (V
), due to remote off or thermal shutdown
conditions. This effectively minimizes current and voltage
stresses on the output MOSFET, the clamp circuit and the
output rectifier during start-up. This feature also helps
minimize output overshoot and prevents saturation of the
transformer during start-up.
Shutdown/Auto-Restart
To minimize
TOPSwitch-GX
power dissipation under fault
conditions, the shutdown/auto-restart circuit turns the power
supply on and off at an auto-restart duty cycle of typically 4%
if an out of regulation condition persists. Loss of regulation
interrupts the external current into the CONTROL pin. V
regu-
lation changes from shunt mode to the hysteretic auto-restart
mode as described in CONTROL pin operation section. When
the fault condition is removed, the power supply output
becomes regulated, V
regulation returns to shunt mode, and
normal operation of the power supply resumes.
Hysteretic Over-Temperature Protection
Temperature protection is provided by a precision analog
circuit that turns the output MOSFET off when the junction
temperature exceeds the thermal shutdown temperature
(140
°
C typical). When the junction temperature cools to
below the hysteretic temperature, normal operation resumes
providing automatic recovery. A large hysteresis of 70
°
C
(typical) is provided to prevent overheating of the PC board
due to a continuous fault condition. V
is regulated in hyster-
etic mode and a 4.8 V to 5.8 V (typical) sawtooth waveform is
present on the CONTROL pin while in thermal shutdown.
Bandgap Reference
All critical
TOPSwitch-GX
internal voltages are derived from
a temperature-compensated bandgap reference. This reference
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| TOP247R-TL | SMPS Controller |
| TOP248F | SMPS Controller |
| TOP248R-TL | SMPS Controller |
| TOP249F | SMPS Controller |
| TOP249R-TL | SMPS Controller |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| TOP247F- | 制造商:POWERINT 制造商全稱:Power Integrations, Inc. 功能描述:TOPSwitch-GX Family Extended Power, Design Flexible, EcoSmart, Integrated Off-line Switcher |
| TOP247FN | 功能描述:交流/直流開關(guān)轉(zhuǎn)換器 125 W 85-265 VAC 165 W 230 VAC RoHS:否 制造商:STMicroelectronics 輸出電壓:800 V 輸入/電源電壓（最大值）:23.5 V 輸入/電源電壓（最小值）:11.5 V 開關(guān)頻率:115 kHz 電源電流:1.6 mA 工作溫度范圍:- 40 C to + 150 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SSO-10 封裝:Reel |
| TOP247FN- | 制造商:POWERINT 制造商全稱:Power Integrations, Inc. 功能描述:TOPSwitch-GX Family Extended Power, Design Flexible, EcoSmart, Integrated Off-line Switcher |
| TOP247FN-TL | 制造商:POWERINT 制造商全稱:Power Integrations, Inc. 功能描述:TOPSwitch-GX Family Extended Power, Design Flexible, EcoSmart, Integrated Off-line Switcher |
| TOP247F-TL | 制造商:POWERINT 制造商全稱:Power Integrations, Inc. 功能描述:TOPSwitch-GX Family Extended Power, Design Flexible, EcoSmart, Integrated Off-line Switcher |
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