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About information presented in this cross reference

The information presented in this cross reference is based on TOSHIBA's selection criteria and should be treated as a suggestion only. Please carefully review the latest versions of all relevant information on the TOSHIBA products, including without limitation data sheets and validate all operating parameters of the TOSHIBA products to ensure that the suggested TOSHIBA products are truly compatible with your design and application.
Please note that this cross reference is based on TOSHIBA's estimate of compatibility with other manufacturers' products, based on other manufacturers' published data, at the time the data was collected.
TOSHIBA is not responsible for any incorrect or incomplete information. Information is subject to change at any time without notice.

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How quick is the protection speed of the electronic fuse?

High-speed protection reduces circuit stress

Conventional glass tube fuses and chip fuses are heated by overcurrent and the conductive parts are melted. However, it takes a few seconds to make a physical blow. The poly switch that can be used repeatedly takes several hundred ms to several seconds to protect it from overcurrent generation, because it utilizes PTC [Note 1] in which resistance increases rapidly due to thermal expansion.
On the other hand, the electronic fuse (eFuse IC) is a semiconductor switch. The circuit is protected at an unprecedented high-speed because an error is detected in the semiconductor circuit and the current path is immediately shut down by MOSFET switch. In addition to being repeatedly usable, the short-circuit protection is 150 ns (Typ.), which is approximately 1 million times quicker than conventional fuses.

[Note 1] PTC: Positive Temperature Coefficient

Comparison of various fuses

 

Electronic fuse

Toshiba eFuse IC

Resettable fuse

(poly switch)

Chip fuse

Glass fuse

Protection method

Shut down by MOSFET switch

Current limit by resistance increase

Blown conductive part

Blown conductive part

Protection speed

150ns (Typ.)

Several hundred ms to several seconds

Several  seconds

Several seconds

Repeated use

Possible

Possible

Not possible

Not possible

eFuse IC utilizes semiconductor-based integrated circuits to provide not only a simple shut down function but also a variety of built-in protective functions. Main features are short-circuit protection, overvoltage clamping (OVP) [Note 2], overcurrent clamping (OCP) [Note 2] , overheat protection, inrush current suppression, reverse current prevention, etc., and conformity to the component standards of the safety standard IEC62368-1 for IT/AV equipment.
This article introduces short-circuit protection as basic function of fuse and lineup classification (overvoltage clamp/recovery operation).

[Note 2]  OCP : Over Current Protection OVP : Over Voltage Protection

Quick short-circuit protection

Quick short-circuit protection

The short-circuit protection function prevents excessive current flowing when the load is short-circuited due to an error. Toshiba eFuse IC has an ultra-high-speed circuit technique to shut down current in 150ns (Typ.) after a short-circuit occurs, which greatly contributes to robust designing of equipment. Unlike conventional fuses, they are not destroyed by a single short-circuit and can be used repeatedly, thus reducing maintenance costs and restoration time required for repairs. The figure below shows a simulated waveform when TCKE812 is supplying power of 12V and the output voltage is shorted steeply.

Lineup classification

Lineup classification

TCKE8xx series has a lineup of clamping voltages at overvoltage and recovery operation types.
The overvoltage clamping voltage is set accordingly to system voltage to prevent an overvoltage being applied to the load. The product with the clamping voltage set to 6.04 V (Typ.) is TCKE805, and 15.1 V (Typ.) is TCKE812. If the overvoltage clamping function is not required, use  TCKE800 that does not have this function.

The recovery operation type is a method to recovery from protective operation to normal operation, and two types are available. The auto-retry type will try to recover automatically until the problem is solved. On the other hand, the latch type latches when the overheat protection is activated, and recovers with an external control signal after the cause of the error is eliminated.

* UVLO: Under Voltage Lock Out

Product Number

TCKE800NA

TCKE800NL

TCKE805NA

TCKE805NL

TCKE812NA

TCKE812NL

Data sheet

PDF (1725 KB)

Stock check

StockChecking

StockChecking

StockChecking

StockChecking

StockChecking

StockChecking

Over voltage clamp

VOVC Typ. (V)

-

6.04

15.1

Recovery operation type

Auto-retry

Latch

Auto-retry

Latch

Auto-retry

Latch

Package

Name

WSON10B

Size

Typ. (mm)

3.00×3.00, t=0.75 Max

Operating

ranges

Input voltage

VIN (V)

4.4 to 18

Output current

IOUT (A)

0 to 5.0

Over current limit accuracy (%)

±11 @Ta= -40 to 85℃、ILIM=4.38A

On-resistance

RON Typ. (mΩ)

28

Other protection functions and safety standards

Application

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