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| 型号： | TNY279GN |
| 厂商： | Power Integrations |
| 文件页数： | 3/24页 |
| 文件大小： | 0K |
| 描述： | IC OFFLINE SWIT OVP OTP HV 8SMD |
| 标准包装： | 50 |
| 系列： | TinySwitch®-III |
| 输出隔离： | 隔离 |
| 频率范围： | 124kHz ~ 140kHz |
| 输出电压： | 700V |
| 功率（瓦特）： | 32W |
| 工作温度： | -40°C ~ 150°C |
| 封装/外壳： | 8-SMD（7 个接脚），鸥形翼 |
| 供应商设备封装： | SMD-8C |
| 包装： | 管件 |
| 配用： | 596-1194-ND - KIT DESIGN REF TINYSWITCH-III |
TNY274-280
pulled from the pin drops to less than a threshold current. A
modulation of the threshold current reduces group pulsing. The
threshold current is between 75 μ A and 115 μ A.
The EN/UV pin also senses line undervoltage conditions through
an external resistor connected to the DC line voltage. If there is
no external resistor connected to this pin, TinySwitch-III detects
its absence and disables the line undervoltage function.
SOURCE (S) Pin:
This pin is internally connected to the output MOSFET source for
high voltage power return and control circuit common.
TinySwitch-III Functional Description
TinySwitch-III combines a high voltage power MOSFET switch
with a power supply controller in one device. Unlike conventional
PWM (pulse width modulator) controllers, it uses a simple
ON/OFF control to regulate the output voltage.
The controller consists of an oscillator, enable circuit (sense and
logic), current limit state machine, 5.85 V regulator, BYPASS/
MULTI-FUNCTION pin undervoltage, overvoltage circuit, and
current limit selection circuitry, over-temperature protection,
current limit circuit, leading edge blanking, and a 700 V power
MOSFET. TinySwitch-III incorporates additional circuitry for line
undervoltage sense, auto-restart, adaptive switching cycle on-
time extension, and frequency jitter. Figure 2 shows the
functional block diagram with the most important features.
Oscillator
The typical oscillator frequency is internally set to an average of
132 kHz. Two signals are generated from the oscillator: the
maximum duty cycle signal (DC MAX ) and the clock signal that
indicates the beginning of each cycle.
The oscillator incorporates circuitry that introduces a small
amount of frequency jitter, typically 8 kHz peak-to-peak, to
minimize EMI emission. The modulation rate of the frequency
jitter is set to 1 kHz to optimize EMI reduction for both average
and quasi-peak emissions. The frequency jitter should be
600
500
V DRAIN
measured with the oscilloscope triggered at the falling edge of
the DRAIN waveform. The waveform in Figure 4 illustrates the
frequency jitter.
Enable Input and Current Limit State Machine
The enable input circuit at the EN/UV pin consists of a low
impedance source follower output set at 1.2 V. The current
through the source follower is limited to 115 μ A. When the
current out of this pin exceeds the threshold current, a low logic
level (disable) is generated at the output of the enable circuit,
until the current out of this pin is reduced to less than the
threshold current. This enable circuit output is sampled at the
beginning of each cycle on the rising edge of the clock signal. If
high, the power MOSFET is turned on for that cycle (enabled). If
low, the power MOSFET remains off (disabled). Since the
sampling is done only at the beginning of each cycle,
subsequent changes in the EN/UV pin voltage or current during
the remainder of the cycle are ignored.
The current limit state machine reduces the current limit by
discrete amounts at light loads when TinySwitch-III is likely to
switch in the audible frequency range. The lower current limit
raises the effective switching frequency above the audio range
and reduces the transformer ?ux density, including the
associated audible noise. The state machine monitors the
sequence of enable events to determine the load condition and
adjusts the current limit level accordingly in discrete amounts.
Under most operating conditions (except when close to no-
load), the low impedance of the source follower keeps the
voltage on the EN/UV pin from going much below 1.2 V in the
disabled state. This improves the response time of the
optocoupler that is usually connected to this pin.
5.85 V Regulator and 6.4 V Shunt Voltage Clamp
The 5.85 V regulator charges the bypass capacitor connected
to the BYPASS pin to 5.85 V by drawing a current from the
voltage on the DRAIN pin whenever the MOSFET is off. The
BYPASS/MULTI-FUNCTION pin is the internal supply voltage
node. When the MOSFET is on, the device operates from the
energy stored in the bypass capacitor. Extremely low power
consumption of the internal circuitry allows TinySwitch-III to
operate continuously from current it takes from the DRAIN pin.
A bypass capacitor value of 0.1 μ F is suf ?cient for both high
frequency decoupling and energy storage.
400
In addition, there is a 6.4 V shunt regulator clamping the
300
200
100
0
136 kHz
128 kHz
BYPASS/MULTI-FUNCTION pin at 6.4 V when current is
provided to the BYPASS/MULTI-FUNCTION pin through an
external resistor. This facilitates powering of TinySwitch-III
externally through a bias winding to decrease the no-load
consumption to well below 50 mW.
BYPASS/MULTI-FUNCTION Pin Undervoltage
The BYPASS/MULTI-FUNCTION pin undervoltage circuitry
disables the power MOSFET when the BYPASS/MULTI-
FUNCTION pin voltage drops below 4.9 V in steady state
operation. Once the BYPASS/MULTI-FUNCTION pin voltage
0
Figure 4.
Frequency Jitter.
5
Time ( μ s)
10
drops below 4.9 V in steady state operation, it must rise back to
5.85 V to enable (turn-on) the power MOSFET.
3
www.powerint.com
Rev. I 01/09
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相关代理商/技术参数 |
参数描述 |
|---|---|
| TNY279GN0152-TL | 制造商:Power Integrations 功能描述: |
| TNY279GN-TL | 功能描述:交流/直流开关转换器 25W 85-265 VAC 32W/230 VAC RoHS:否 制造商:STMicroelectronics 输出电压:800 V 输入/电源电压（最大值）:23.5 V 输入/电源电压（最小值）:11.5 V 开关频率:115 kHz 电源电流:1.6 mA 工作温度范围:- 40 C to + 150 C 安装风格:SMD/SMT 封装 / 箱体:SSO-10 封装:Reel |
| TNY279GTL | 制造商:POWERINT 制造商全称:Power Integrations, Inc. 功能描述:Energy Efficient, Off-Line Switcher with Enhanced Flexibility and Extended Power Range |
| TNY279P | 制造商:POWERINT 制造商全称:Power Integrations, Inc. 功能描述:Energy Efficient, Off-Line Switcher with Enhanced Flexibility and Extended Power Range |
| TNY279PG | 功能描述:交流/直流开关转换器 25 W (85-265 VAC) 32 W (230 VAC) RoHS:否 制造商:STMicroelectronics 输出电压:800 V 输入/电源电压（最大值）:23.5 V 输入/电源电压（最小值）:11.5 V 开关频率:115 kHz 电源电流:1.6 mA 工作温度范围:- 40 C to + 150 C 安装风格:SMD/SMT 封装 / 箱体:SSO-10 封装:Reel |
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