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參數資料
| 型號： | TISP61521DR |
| 廠商： | BOURNS INC |
| 元件分類： | 保護電路 |
| 英文描述： | DUAL FORWARD-CONDUCTING P-GATE THYRISTORS PROGRAMMABLE OVERVOLTAGE PROTECTORS |
| 中文描述： | TELECOM, SURGE PROTECTION CIRCUIT, PDSO8 |
| 封裝： | PLASTIC, MS-012, SO-8 |
| 文件頁數： | 6/11頁 |
| 文件大?。?/td> | 191K |
| 代理商： | TISP61521DR |
APRIL 2001 REVISED FEBRUARY 2005
Specifications are subject to change without notice.
Customers should verify actual device performance in their specific applications.
TISP61521 SLIC Protector
Gated Protectors
This section covers three topics. First, it is explained why gated protectors are needed. Second, the voltage limiting action of the protector is
described. Third, an example application circuit is described.
Purpose of Gated Protectors
Fixed voltage thyristor overvoltage protectors have been used since the early 1980s to protect monolithic SLICs (Subscriber Line Interface
Circuits) against overvoltages on the telephone line caused by lightning, a.c. power contact and induction. As the SLIC was usually powered
from a fixed voltage negative supply rail, the limiting voltage of the protector could also be a fixed value. The TISP1072F3 is a typical example
of a fixed voltage SLIC protector.
SLICs have become more sophisticated. To minimize power consumption, some designs automatically adjust the driver supply voltage to a
value that is just sufficient to drive the required line current. For short lines, the supply voltage would be set low, but for long lines, a higher
supply voltage would be generated to drive sufficient line current. The optimum protection for this type of SLIC would be given by a protection
voltage which tracks the SLIC supply voltage. This can be achieved by connecting the protection thyristor gate to the SLIC VBATH supply,
Figure 3. This gated (programmable) protection arrangement minimizes the voltage stress on the SLIC, no matter what value of supply voltage.
APPLICATIONS INFORMATION
Figure 3. Negative Overvoltage Condition
C1
220 nF
I
G
Th5
SLIC
V
BAT
SLIC
PROTECTOR
TISP
61521
I
K
AI6XABA
Th5
SLIC
V
BAT
SLIC
PROTECTOR
TISP
61521
C1
220 nF
I
F
AI6XACA
Figure 4. Positive Overvoltage Condition
Operation of Gated Protectors
Figure 3 and Figure 4 show how the TISP61521 limits negative and positive overvoltages. Positive overvoltages (Figure 4) are clipped by the
antiparallel diode of Th5 and the resulting current is diverted to ground. Negative overvoltages (Figure 3) are initially clipped close to the SLIC
negative supply rail value (VBATH). If sufficient current is available from the overvoltage, then Th5 will switch into a low voltage on-state
condition. As the overvoltage subsides, the high holding current of Th5 prevents d.c. latchup. The protection voltage will be the sum of the
gate supply (VBATH) and the peak gate-cathode voltage (VGK(BO)). The protection voltage will be increased if there is a long connection
between the gate decoupling capacitor, C1, and the gate terminal. During the initial rise of a fast impulse, the gate current (IG) is the same as
the cathode current (IK). Rates of 70 A/
μ
s can cause inductive voltages of 0.7 V in 2.5 cm of printed wiring track. To minimize this inductive
voltage increase of protection voltage, the length of the capacitor to gate terminal tracking should be minimized. Inductive voltages in the
protector cathode wiring will also increase the protection voltage. These voltages can be minimized by routing the SLIC connection through
the protector as shown in Figure 6.
Figure 5, which has a 10 A/
μ
s rate of impulse current rise, shows a positive gate charge (QGS) of about 0.1
μ
C. With the 0.1
μ
F gate
decoupling capacitor used, the increase in gate supply is about 1 V (= QGS/C1). This change is just visible on the -72 V gate voltage, VBATH.
But the voltage increase does not directly add to the protection voltage, as the supply voltage change reaches a maximum at 0.4
μ
s, when the
gate current reverses polarity, and the protection voltage peaks earlier at 0.3
μ
s. In Figure 5, the peak clamping voltage (V(BO)) is -77.5 V, an
increase of 5.5 V on the nominal gate supply voltage. This 5.5 V increase is the sum of the supply rail increase at that time, (0.5 V), and the
protection circuit’s cathode diode to supply rail breakover voltage (5 V). In practice, use of the recommended 220 nF gate decoupling capacitor
would give a supply rail increase of about 0.3 V and a V(BO) value of about -77.3 V.
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相關代理商/技術參數 |
參數描述 |
|---|---|
| TISP61521DR-S | 功能描述:SCR Dual P Gate Forward Conducting RoHS:否 制造商:STMicroelectronics 最大轉折電流 IBO:480 A 額定重復關閉狀態(tài)電壓 VDRM:600 V 關閉狀態(tài)漏泄電流（在 VDRM IDRM 下）:5 uA 開啟狀態(tài) RMS 電流 (It RMS): 正向電壓下降:1.6 V 柵觸發(fā)電壓 (Vgt):1.3 V 最大柵極峰值反向電壓:5 V 柵觸發(fā)電流 (Igt):35 mA 保持電流（Ih 最大值）:75 mA 安裝風格:Through Hole 封裝 / 箱體:TO-220 封裝:Tube |
| TISP61521DS | 制造商:Bourns Inc 功能描述: |
| TISP61521D-S | 制造商:BOURNS 制造商全稱:Bourns Electronic Solutions 功能描述:DUAL FORWARD-CONDUCTING P-GATE THYRISTORS PROGRAMMABLE OVERVOLTAGE PROTECTORS |
| TISP61CAP3 | 制造商:POINN 制造商全稱:Power Innovations Ltd 功能描述:PROGRAMMABLE OVERVOLTAGE PROTECTOR |
| TISP61CAP3D-S | 制造商:Bourns Inc 功能描述: |
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