- 您现在的位置：买卖IC网 > PDF目录19752 > TOP256GN-TL (Power Integrations)IC OFFLINE SWIT PROG OVP 8SMD PDF资料下载
参数资料
| 型号： | TOP256GN-TL |
| 厂商： | Power Integrations |
| 文件页数： | 26/50页 |
| 文件大小： | 0K |
| 描述： | IC OFFLINE SWIT PROG OVP 8SMD |
| 产品培训模块： | TOPSwitch® HX General Introduction |
| 标准包装： | 1 |
| 系列： | TOPSwitch®-HX |
| 输出隔离： | 隔离 |
| 频率范围： | 119kHz ~ 145kHz |
| 输出电压： | 700V |
| 功率（瓦特）： | 63W |
| 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： | 标准包装 |
| 配用： | 596-1193-ND - KIT REF DESIGN TOP HX FOR TOP258 |
| 其它名称： | 596-1182-6 |
第1页第2页第3页第4页第5页第6页第7页第8页第9页第10页第11页第12页第13页第14页第15页第16页第17页第18页第19页第20页第21页第22页第23页第24页第25页当前第26页第27页第28页第29页第30页第31页第32页第33页第34页第35页第36页第37页第38页第39页第40页第41页第42页第43页第44页第45页第46页第47页第48页第49页第50页
TOP252-262
TOPSwitch-HX Design Considerations
Power Table
The data sheet power table (Table 1) represents the maximum
practical continuous output power based on the following
conditions:
1. 12 V output.
2. Schottky or high efficiency output diode.
3. 135 V reflected voltage (V OR ) and efficiency estimates.
4. A 100 VDC minimum for 85-265 VAC and 250 VDC mini-
mum for 230 VAC.
5. Sufficient heat sinking to keep device temperature ≤100 ° C.
6. Power levels shown in the power table for the M/P package
device assume 6.45 cm 2 of 610 g/m 2 copper heat sink area
in an enclosed adapter, or 19.4 cm 2 in an open frame.
The provided peak power depends on the current limit for the
respective device.
TOPSwitch-HX Selection
Selecting the optimum TOPSwitch-HX depends upon required
maximum output power, efficiency, heat sinking constraints,
system requirements and cost goals. With the option to
externally reduce current limit, an Y, E/L or M package
TOPSwitch-HX may be used for lower power applications
where higher efficiency is needed or minimal heat sinking is
available.
Input Capacitor
The input capacitor must be chosen to provide the minimum
DC voltage required for the TOPSwitch-HX converter to
maintain regulation at the lowest specified input voltage and
maximum output power. Since TOPSwitch-HX has a high
DC MAX limit and an optimized dual slope line feed forward for
ripple rejection, it is possible to use a smaller input capacitor.
For TOPSwitch-HX, a capacitance of 2 m F per watt is possible
for universal input with an appropriately designed transformer.
Primary Clamp and Output Reflected Voltage V OR
A primary clamp is necessary to limit the peak TOPSwitch-HX
drain to source voltage. A Zener clamp requires few parts and
takes up little board space. For good efficiency, the clamp
Zener should be selected to be at least 1.5 times the output
reflected voltage V OR , as this keeps the leakage spike conduction
time short. When using a Zener clamp in a universal input
application, a V OR of less than 135 V is recommended to allow
for the absolute tolerances and temperature variations of the
Zener. This will ensure efficient operation of the clamp circuit
and will also keep the maximum drain voltage below the rated
breakdown voltage of the TOPSwitch-HX MOSFET. A high V OR
is required to take full advantage of the wider DC MAX of
TOPSwitch-HX. An RCD clamp provides tighter clamp voltage
tolerance than a Zener clamp and allows a VOR as high as 150
V. RCD clamp dissipation can be minimized by reducing the
external current limit as a function of input line voltage (see
Figures 23 and 36). The RCD clamp is more cost effective than
the Zener clamp but requires more careful design (see Quick
Design Checklist).
Output Diode
The output diode is selected for peak inverse voltage, output
current, and thermal conditions in the application (including heat
26
Rev. H 06/13
sinking, air circulation, etc.). The higher DC MAX of TOPSwitch-HX,
along with an appropriate transformer turns ratio, can allow the
use of a 80 V Schottky diode for higher efficiency on output
voltages as high as 15 V (see Figure 41).
Bias Winding Capacitor
Due to the low frequency operation at no-load, a 10 m F bias
winding capacitor is recommended.
Soft-Start
Generally, a power supply experiences maximum stress at
start-up before the feedback loop achieves regulation. For a
period of 17 ms, the on-chip soft-start linearly increases the
drain peak current and switching frequency from their low
starting values to their respective maximum values. This
causes the output voltage to rise in an orderly manner, allowing
time for the feedback loop to take control of the duty cycle.
This reduces the stress on the TOPSwitch-HX MOSFET, clamp
circuit and output diode(s), and helps prevent transformer
saturation during start-up. Also, soft-start limits the amount of
output voltage overshoot and, in many applications, eliminates
the need for a soft-finish capacitor.
EMI
The frequency jitter feature modulates the switching frequency
over a narrow band as a means to reduce conducted EMI peaks
associated with the harmonics of the fundamental switching
frequency. This is particularly beneficial for average detection
mode. As can be seen in Figure 45, the benefits of jitter increase
with the order of the switching harmonic due to an increase in
frequency deviation. Devices in the P, G or M package and
TOP259-261YN operate at a nominal switching frequency of
66 kHz. The FREQUENCY pin of devices in the TOP254-258 Y
and E packages offer a switching frequency option of 132 kHz or
66 kHz. In applications that require heavy snubber on the drain
node for reducing high frequency radiated noise (for example,
video noise sensitive applications such as VCRs, DVDs, monitors,
TVs, etc.), operating at 66 kHz will reduce snubber loss, resulting
in better efficiency. Also, in applications where transformer size is
not a concern, use of the 66 kHz option will provide lower EMI
and higher efficiency. Note that the second harmonic of 66 kHz
is still below 150 kHz, above which the conducted EMI
specifications get much tighter. For 10 W or below, it is possible
to use a simple inductor in place of a more costly AC input
common mode choke to meet worldwide conducted EMI limits.
Transformer Design
It is recommended that the transformer be designed for
maximum operating flux density of 3000 Gauss and a peak flux
density of 4200 Gauss at maximum current limit. The turns
ratio should be chosen for a reflected voltage (V OR ) no greater
than 135 V when using a Zener clamp or 150 V (max) when
using an RCD clamp with current limit reduction with line
voltage (overload protection). For designs where operating
current is significantly lower than the default current limit, it is
recommended to use an externally set current limit close to the
operating peak current to reduce peak flux density and peak
power (see Figures 22 and 35). In most applications, the tighter
current limit tolerance, higher switching frequency and soft-start
features of TOPSwitch-HX contribute to a smaller transformer
when compared to TOPSwitch-GX.
www.powerint.com
相关PDF资料 |
PDF描述 |
|---|---|
| TAJC156K010RNJ | CAP TANT 15UF 10V 10% 2312 |
| EEM03DRKN | CONN EDGECARD 6POS DIP .156 SLD |
| ABM43DSEF-S243 | CONN EDGECARD 86POS .156 EYELET |
| TAJC106K010H | CAP TANT 10UF 10V 10% 2312 |
| NLCV25T-R68M-PFR | INDUCTOR POWER .68UH 1008 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| TOP256LG | 功能描述:交流/直流开关转换器 64W (85-264VAC) 88W (230V AC) 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 |
| TOP256LN | 功能描述:交流/直流开关转换器 64W (85-264VAC) 88W (230V AC) 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 |
| TOP256MG | 功能描述:交流/直流开关转换器 26W/40W PK 85-264VAC 34W/63W PK (230V AC) 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 |
| TOP256MN | 功能描述:交流/直流开关转换器 Off-Line Switcher IC 26W/64W PK 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 |
| TOP256PG | 功能描述:交流/直流开关转换器 26W/40W PK 85-264VAC 34W/63W PK (230V AC) 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 |
发布紧急采购，3分钟左右您将得到回复。