PolySwitch® Resettable Devices

Littelfuse PolySwitch和Poly-Fuse设备是聚合物正温度系数(PPTC)器件,其提供可恢复的过电流保护替代方案,从而减少保修,服务和维修费用。适用于需要常用过流条件或需要恒定的正常运行时间的情况下,可重置的PTCS(PPTC)通常用于消费电子,电源线,电信,I / O端口,过程控制和医疗设备保护应用。

由于流量增加,PTCS增加阻力随温度升高。设计用于限制不安全的电流,同时允许恒定的安全电流水平,当故障移除时,电阻将自动“复位”,并且温度返回到安全水平。

Surface mount resettable PTC devicesprovide overcurrent protection for applications where space is at a premium and resettable protection is desired. Package size varies from 0402 to 3425, while hold current ranges from 50mA to 7.0A.洛罗,0603L.,0805L,1206L.,1210L,1812L,2016L,2920L,250年代,femtoSMD,Picosmd.,nanosmd.,microSmd.,miniSMD,沮丧,SMDC.,,SMD,纳米姆斯,microASMD,miniASMD,ASMD.

径向可引入可复位的PTCSare designed to provide overcurrent protection for applications where space is not a concern and resettable protection is preferred.USBR.,16.,30.R,60.R,72R.,250r.,600r.,RGEF,RUEF,RXEF,RHEF,RKEF,AGRF,AHRF.,Ahef..

电池表带可复位PTCSprovide reliable, non-cycling protection against overcharging and short circuits events for rechargeable battery cells where resettable protection is desired.vlr.,VLP.,VTP,MXP.,MGP,SRP,LR4.,RSD.

New LittelfuseLo Rho重新注入PPTCoffers ultra-low normal operating resistance while maintaining the same performance of other Littelfuse PPTC products and are available inSurface Mount Low Rho SMD SeriesandSurface Mount Lo Rho Series.

电信resettable PTC Seriesis designed to protect against short-duration high-voltage fault currents (power cross or power induction surge) typically found in telecommunications and networking applications. The250r.,250年代,TRF250,TSL250,TS250,TCF250andTSV250系列可用于帮助电信网络设备满足ITU K.20和K.21中规定的保护要求。这600r.,TRF600,TR600,TS600andTSM600series is designed to be used in applications that need to meet the requirements of GR–1089-CORE and UL60950/ EN60950/IEC60950.

Littelfuse plants for PolySwitch devices are ISO/TS 16949:2009 and ISO 9001:2008 certified.

Traditional Fuses vs. PTCs

保险丝and PTCs are both overcurrent protection devices, though each offer their own unique operating characteristics and benefits. Understanding the differences between the two technologies should make the choice in selection easier, depending on the application.

最明显的差异是PTCS自动重置,而传统保险丝需要在绊倒后更换。虽然在大多数相似的过电流事件之后,熔丝将完全停止电流(可能在关键应用中可能需要的流程),但PTC继续使得能够使函数相应于extroun案例。

由于它们自动重置,许多电路设计人员在预期过流事件的情况下选择PTCS,并且在维持低保修和服务成本,恒定系统正常运行时间和/或用户透明度的情况下,请达到溢价。它们通常在难以访问或远程位置的电路​​中选择,熔断器更换是困难的。

这re are several other operating characteristics to be considered that distinguish PTCs and fuses, and it is also best to test and verify device performance before use within the end application.

更多了解有关传统保险丝与PTC的更多信息click here.

PTC特征和术语

可以通过使用传统的保险丝或PTC(正温度系数)装置来实现过电路保护。PTC通常用于各种电信,计算机,消费电子产品,电池和医疗电子产品应用,其中过电流事件是常见的和自动沉积性的。

Littelfuse提供具有以下一般形式和功能的PTC,并具有各种尺寸和能力:

Surface Mount Devices:

  • 全方位的紧凑型脚印
  • 低保持电流
  • Very fast trip time
  • 低阻

径向牵引系列:

  • 高达600VDC的保护装置
  • A very high hold current
  • 低跳闸到保持电流比率
  • 低阻

Battery Strap Devices:

  • A narrow low profile design
  • 可焊接带镍端子
  • 低阻–for extended battery run time

如果您的应用要求落在我们的产品范围之外,在某些情况下,我们可以提供定制的解决方案。请联系Littelfuse获取更多信息。

Littelfuse PTC Characteristics

Both Polymeric (Positive Temperature Coefficient) PTC and traditional Fuse devices react to heat generated by the excessive current flow in a circuit. A fuse melts open, interrupting the current flow whereas a PTC limits current flow as it rises in temperature, changing from low to high resistance state. In both cases this condition is called "tripping." The graph at right shows the typical response of a PTC to temperature.

Littelfuse聚合物PTC主要由与石墨混合的高密度聚乙烯制成。在过电流事件期间,聚合物PTC将热和膨胀,这又导致导电颗粒断裂接触并停止电流。

在发生过载后重置设备的一般过程是删除电源并允许设备冷却。

Leakage Current

When a PTC is in a "tripped state" it protects the circuitry by limiting the current flow to a low leakage level. Leakage current can range from less than a hundred milliamps (mA) at rated voltage up to a few hundred milliamps (mA) at lower voltages. Fuses on the other hand completely interrupt the current flow when tripped, and this open circuit results in no leakage current when subjected to an overload current.

Interrupting Rating

PTCS被评定为最大短路电流,额定电压也称为“断开容量”或IMAX。该故障电流水平是设备可以安全地承受的最大电流,请记住,PTC实际上不会中断电流(参见上面的漏电流)。典型的Littelfuse PTC短路额定值为40A;或者对于电池表带PTC,该值可以达到100A。保险丝实际上确实在响应过载和中断额定值范围内中断电流,从额定电压下达10,000(a)安培的数十台(A)。

Operating Voltage Rating

一般用途Littelfuse PTC在60V高于60V时,保险丝额定到600V。

保持当前评级

PTCS的保持(操作)电流额定值最长可达14A,而保险丝的最大水平可超过30A。

Resistance

Reviewing product specifications indicates that similarly rated PTCs have about twice (sometimes more) the resistance of fuses.

代理批准s

Littelfuse PTCs are Recognized under the Component Program of Underwriters Laboratories to UL Standard 1434 for Thermistors. The devices have also been certified under the CSA Component Acceptance Program.

时流特征

Comparing the time-current curves of PTCs to time-current curves of fuses show that the speed of response for a PTC is similar to the time delay of a Littelfuse Slo-Blo® fuse.

温度更新

PTC的有用上限通常为85°C,而保险丝的最大工作温度为125°C。

环境温度影响是除了normal rerating. PTCs hold and trip rating must be rerated when applied at conditions other than room ambient. For example, any rise in ambient temperature will decrease the hold current rating as well as the trip current. A reduction in ambient temperature will increase the trip current as well as the hold current.

这temperature rerating curves in the table below compare PTCs to fuses and illustrate that more rerating is required for a PTC at a given temperature.

温度更新Curves Comparing PTCs to Fuses

图表钥匙 Temperature-Rerating-Curves-Comparing-PTCs-to-Fuses
曲线A.
薄膜保险丝和313系列(.010至.150A)

曲线B.
平底锅®,Nano2.®,pico®, Blade Terminal,
专用和其他铅和墨盒保险丝
(except 313.010 – .150A)

曲线C.
Resettable PTCs

PTC通常用作电路保护,在敏感组分处于过流条件损坏的持续风险中。PTC在曝光到故障电流后,PTC将自己重置的能力使得它们在不容易被用户或技术人员无法访问的电路中,或者需要持续正常运行时间。

典型应用包括个人计算机的端口保护(USB,FireWire,键盘/鼠标和串行端口),外围设备(硬盘驱动器,视频卡和集线器),手机,电池组,工业控制,照明镇流器和电机控制。

这chart below is meant as a quick guide in narrowing to a Littelfuse PTC device that may be appropriate to certain end applications.

有关详细的申请援助,请访问我们的Application Design Center Site.

SURFACE MOUNT
洛罗 0603L. 0805L 1206L. 1210L 1812L 2016L 2920L 250年代
电信
UL60950,TIA-968-A,GR-1089 REQ的
ITU-T Recoomendations
CPE (Customer Premises Equipment)
Analog Line Card
T1/E1/J1 And HDSL
isdn.
ADSL
有线电话
PBX / KTS和关键电话系统
电脑 CPU
USB
IEEE1284 Parallel Data Bus
IEEE 802.3.
IEEE 1394.
I/O Ports
PC Card
SCSI
视频端口
HDMI / LCD显示器
Consumer
Electronics
套上盒子
喇叭
智能读卡器
手机
线性AC / DC适配器
Portable Electronic Input Port
Electromagnetic Loads, Motor
Solenoid Protection
Medical
electronic
Voltage / Current Input Terminal
径向引线 电池表带
USBR. 16. 30.R 60.R 72R. 250r. 600r. LR LT SL ST VL VT
Battery Lithium Cell
Battery Pack
UL60950,TIA-968-A,GR-1089 REQ的
ITU-T Recoomendations
CPE (Customer Premises Equipment)
Analog Line Card
T1/E1/J1 And HDSL
isdn.
ADSL
有线电话
PBX / KTS和关键电话系统
电脑 CPU
USB
IEEE1284 Parallel Data Bus
IEEE 802.3.
IEEE 1394.
I/O Ports
PC Card
SCSI
视频端口
液晶显示器
消费类电子产品
喇叭
线性AC / DC适配器
Electromagnetic Loads, Motor
Solenoid Protection

Note: The application summary is for reference only. Determination of suitability for a specific application is the responsibility of the customer.

r

典型的PTC电路保护设计

这following are examples of typical circuits using Littelfuse PTCs in combination with other Littelfuse circuit protection devices to provide a comprehensive protection solution. Contact a Littelfuse application expert for design assistance or visit www.kyqhra.com/designcenteror //www.kyqhra.com/PTCs for additional information. Be sure to to veryify specifications and test device performance before use in the end application.

以太网供电

PTC  - 电源以太网

LI-ION Battery Pack

PTC-LI离子电池组

USB 1.1

PTC-USB-1-1

USB 2.0

PTC-USB2-0.

IEEE 1394.- Firewire

PTC-IEEE-1394-Firewire

尖端/环电路 - 金属

PTC-Tip-Ring-Circuit-Metallic

PTC Selection Worksheet

  1. 定义电路操作参数

    安培正常运行电流:

    伏特的正常工作电压:

    最大中断电流:

    环境温度:

    Typical overload current:

    Required opening time at specified overload:

    瞬态脉冲预计:

    Agency approvals:

    安装类型/表单因子:

    典型抵抗(电路中):

  2. Select the proper circuit protection component.

    (请参阅下面的PTC选择表和使用数据表的规格)

  3. Determine the opening time at fault.

    请参阅每个PTC系列的时间电流(T-C)曲线,以确定所选部件是否在应用程序的约束中运行。

    如果设备打开太快,则应用程序可能会遇到滋扰操作。如果设备不足,过电流可能会损坏下游组件。

    确定选择德维克的开放时间e, locate the overload current on the X-axis of the appropriate T-C Curve and follow its line up to its intersection with the curve. At this point read the time tested on the Y-axis. This is the average opening time for that device.

    如果过载电流落在曲线的右侧,则设备将打开。如果过载电流位于曲线的左侧,则设备将无法操作。

  4. 验证环境操作参数。

    确保应用电压小于或等于设备的额定电压,并且操作温度限制在设备指定的那些内。

  5. 验证设备的尺寸。

    Compare the maximum dimensions of the device to the space available in the application. The dimension of each product is included within each data sheets on the following pages.

  6. 在实际应用中测试所选产品。

PTC选择表

类型 Surface Mount
Series 0603L. 0805L 1206L. 1210L 1812L 2016L 2920L 250年代
芯片尺寸 0603 (1608) 0805 (2012) 1206(3216) 1210 (3225) 1812 (4532) 2016年(5041) 2920(7351)
保持电流(i抓住) 0.10 - 0.35 a 0.10 - 1.00 a 0.125 - 1.50 a 0.05 - 1.50 a 0.10 - 2.60 a 0.30 - 2.00 a 0.30 - 3.00 a 0.13A
Max Voltage (VMAX) 6 –15 V 6 –15 V 6 – 30 V 6 – 30 V 6 - 60 V 6 - 60 V 6 - 60 V 60 V.
最大故障电流(iMAX) 40 A. 40/100 a 100 A. 10/100 a 10 / 20 / 100 A 20/40 a 10 / 40 A 3 A.
工作温度范围 -40ºC to 85ºC
代理批准 PTC-Surface-Mount-Agency-ApprovalPTC-Surface-Mount-Agency-Approval PTC-Surface-Mount-Agency-Approval
符合rohs
PTC-Surface-Mount-RoHS兼容
是的
无铅
PTC-表面安装无铅
是的
类型 径向引线
Series USBR. 16. 30.R 60.R 72R. 250r. 600r.
保持电流(i抓住) 0.75 - 2.50 a 2.50 - 14.00 a 0.90 - 9.00 a 0.10- 3.75 A 0.20 - 3.75 A 0.08- 0.18 A 0.15- 0.16 A
Max Voltage (VMAX) 6 / 16 V 16 V 30 V. 60 V. 72.V 60/250 V. 60/600 v
最大故障电流(iMAX) 40 A. 100 A. 40 A. 40 A. 40 A. 3/10 a 3 A.
工作温度范围 -40ºC to 85ºC
代理批准 PTC-Radial-Leathed-Ordio-ApprovalPTC-Radial-Leathed-Ordio-Approval
符合rohs
PTC-Radial-Leaded-RoHS-Compliant
是的
无铅
PTC-radial-Lign-Ligh-in无铅
是的
类型 Battery Strap
Series LR LT ST VL VT
保持电流(i抓住) 1.90 - 7.30 A 0.70 - 3.40 A 1.20 - 1.75 A 1.70 - 2.30 A 1.70 - 2.40 A
Max Voltage (VMAX) 15 / 20 V 15 / 24V 15 V 12 V 16 V
最大故障电流(iMAX) 100A
工作温度范围 -40ºC to 85ºC
代理批准 PTC-Battery-Strap-Agency批准PTC-Battery-Strap-Agency批准
符合rohs
PTC-Battery-Strap-RoHS-Compliant
是的
无铅
PTC-电池 - 带状无铅
是的

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