參數(shù)資料
型號(hào)： TOP250R
英文描述： Up to 290 W Extended power. design flexible.
中文描述： 高達(dá)290瓦的擴(kuò)展能力。設(shè)計(jì)靈活。
文件頁(yè)數(shù)： 6/52頁(yè)
文件大?。?/td> 468K
代理商： TOP250R
TOP242-250
6
K
9/03
supply under-voltage comparator keeps V
within a window
of typically 4.8 V to 5.8 V by turning the high-voltage current
source on and off as shown in Figure 8. The auto-restart
circuit has a divide-by-eight counter which prevents the output
MOSFET from turning on again until eight discharge/charge
cycles have elapsed. This is accomplished by enabling the
output MOSFET only when the divide-by-eight counter reaches
full count (S7). The counter effectively limits
TOPSwitch-GX
power dissipation by reducing the auto-restart duty cycle to
typically 4%. Auto-restart mode continues until output
voltage regulation is again achieved through closure of the
feedback loop.
Design Ideas 4
Quality and Reliability 6
Package Information 7
~
DPA-SwitchDC-DC Seminar 8
LinkSwitch & TinySwitch-IIAC-DC Seminar 9
TOPSwitch-GXAC-DC Seminar 10
Sales Representatives and Distributors 11
~
~
PI-2545-082299
S1
S2
~
S6
S7
S1
S2
~
S6
S7
S0
S1
S7
S0
S0
5.8 V
S7
0 V
0 V
0 V
V
LINE
V
C
V
DRAIN
V
OUT
0 V
Note: S0 through S7 are the output states of the auto-restart counter
2
1
2
3
4
~
~
~
S6
S7
~
~
~
V
UV
~
~
S2
CONTROL (C) Pin Operation
The CONTROL pin is a low impedance node that is capable of
receiving a combined supply and feedback current. During
normal operation, a shunt regulator is used to separate the
feedback signal from the supply current. CONTROL pin
voltage V
is the supply voltage for the control circuitry
including the MOSFET gate driver. An external bypass
capacitor closely connected between the CONTROL and
SOURCE pins is required to supply the instantaneous gate drive
current. The total amount of capacitance connected to this pin
also sets the auto-restart timing as well as control loop
compensation.
When rectified DC high voltage is applied to the DRAIN pin
during start-up, the MOSFET is initially off, and the
CONTROL pin capacitor is charged through a switched high
voltage current source connected internally between the DRAIN
and CONTROL pins. When the CONTROL pin voltage V
C
reaches approximately 5.8 V, the control circuitry is activated
and the soft-start begins. The soft-start circuit gradually
increases the duty cycle of the MOSFET from zero to the
maximum value over approximately 10 ms. If no external
feedback/supply current is fed into the CONTROL pin by the
end of the soft-start, the high voltage current source is turned
off and the CONTROL pin will start discharging in response
to the supply current drawn by the control circuitry. If the
power supply is designed properly, and no fault condition such
as open loop or shorted output exists, the feedback loop will
close, providing external CONTROL pin current, before the
CONTROL pin voltage has had a chance to discharge to the
lower threshold voltage of approximately 4.8 V (internal supply
under-voltage lockout threshold). When the externally fed
current charges the CONTROL pin to the shunt regulator
voltage of 5.8 V, current in excess of the consumption of the
chip is shunted to SOURCE through resistor R
as shown in
Figure 2. This current flowing through R
controls the duty
cycle of the power MOSFET to provide closed loop regulation.
The shunt regulator has a finite low output impedance Z
that
sets the gain of the error amplifier when used in a primary
feedback configuration. The dynamic impedance Z
of the
CONTROL pin together with the external CONTROL pin
capacitance sets the dominant pole for the control loop.
When a fault condition such as an open loop or shorted output
prevents the flow of an external current into the CONTROL
pin, the capacitor on the CONTROL pin discharges towards
4.8 V. At 4.8 V, auto-restart is activated which turns the output
MOSFET off and puts the control circuitry in a low current
standby mode. The high-voltage current source turns on and
charges the external capacitance again. A hysteretic internal
Oscillator and Switching Frequency
The internal oscillator linearly charges and discharges an
internal capacitance between two voltage levels to create a
Figure 8. Typical Waveforms for (1) Power Up (2) Normal Operation (3) Auto-restart (4) Power Down.
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
TOP250R- 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
TOP250RN- 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
TOP250RN-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
TOP250R-TL 功能描述:交流/直流開(kāi)關(guān)轉(zhuǎn)換器 55 W 85-265 VAC 82 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(kāi)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
TOP250Y 功能描述:交流/直流開(kāi)關(guān)轉(zhuǎn)換器 210 W 85-265 VAC 290 W 230 VACX 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(kāi)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
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