Toshiba has recently introduced the Toshiba TCKE9 reusable e-fuse (electronic fuse) series, a new lineup of e-fuse ICs that can be used repeatedly, to protect power supply lines from various electrical faults like overcurrent, overvoltage, overtemperature, and short circuits. These new chips integrate various protection features into a single chip which simplifies circuit design and reduces component count compared to how a traditional protection circuit with multiple components is designed.
This new line of products offers different ICs with different voltage ratings and adjustable current settings, alongside two reset modes auto-retry and latching. All these features make this e-fuse useful for applications like laptops, wearables, audio/video equipment, and industrial applications like automation systems, robotics, and many other applications.
Toshiba TCKE9 reusable e-fuse Specification
- Input Voltage – 2.7V to 23V (Maximum – 25V)
- Output Current – 0 to 4.0A (Adjustable overcurrent limit – 0.5A to 4.0A via external resistor)
- ON Resistance (RON)
- 34mΩ where the input voltage (VIN) is 4V or higher, with an output current (IOUT) of 1.5A.
- 36mΩ where the input voltage (VIN) is between 2.7V and 4V, and the ON resistance typically increases 36mΩ, with output current of 1.5A.
- Overvoltage Clamp Options
- TCKE903 – 3.87V (Typical)
- TCKE905 – 5.7V (Typical)
- TCKE912 – 13.7V (Typical)
- TCKE920 – 22.2V (Typical)
- Slew Rate Control – Adjustable via external capacitance for inrush current reduction
- Under Voltage Lockout (UVLO) – Adjustable via an external resistor
- Fault Response – Auto-retry or latched
- Response Times
- Overvoltage Clamp – 6.0μs (IOUT = 4A)
- Short Circuit – 2.0μs
- Current Limit – 80μs
- Thermal Shutdown Protection – Threshold at 155°C (Typical) with 20°C hysteresis
- Quiescent Current
- ON State – 180μA to 190μA (Typical, depending on the version)
- OFF State – 0.07μA to 2.55μA
- FLAG Output – Open-drain, low when fault detected
- Weight – 7.99mg (Typical)
- Operating Temperature Range – -40°C to 125°C
- Certification – IEC62368-1 (Under planning)
- Package Dimension – WSON8 (2.0mm x 2.0mm x 0.8mm, 0.5mm pitch)
The Toshiba TCKE9 reusable e-fuse has mainly two varients the Auto-retry type (TCKE9XXNA) and the Latched type (TCKE9XXNL) ICs. The auto-retry feature detects overcurrent and tries to limit the overcurrent. If the overcurrent persists the IC overheats and the internal circuitry shuts it down as a protective measure. In the case of latch type, overheat protection operation is latched. To recover from this state, the device must be restarted by applying a control signal on the EN/UVLO pin. The protection operation remains active until it is manually restarted. You can find detailed information about this IC on the datasheet, and some additional information can be found on the press release.
While searching for more information about Toshiba I found out that Nexperia has also launched two new e-fuses with similar features namely the NPS3102A and NPS3102B (PDF). Like Toshiba, the A variant is a latch-type IC whereas the B variant is the auto-retry type. Compared to Toshiba both the ICs has a max current rating of 13.5A with an operating voltage of 21V. Other than that, other features like overcurrent, overvoltage, excess inrush current, and load faults stay the same. On top of that, this IC features 20μs over-current shut-off, and 2μs short-circuit response and both the ICs have a low RDS(on) of 17mΩ.
Like Toshiba and Nexperia, ST has also released their version of an e-fuse for the automotive environment which they are calling an intelligent automotive circuit breaker. The ST VNF9Q20F is a quad-channel intelligent e-fuse IC with integrated high-side MOSFET drivers, which ST mentions that each can be controlled independently with respect to the other. It features ST’s proprietary fast-acting STI2Fuse technology for fault protection within 100µs, along with programmable current limits and latch-off or auto-retry modes. Additionally, the chip also has SPI pins for diagnostics, a 10-bit ADC, fault registers, and a failsafe mode for reliability.
The Toshiba TCKE9 e-fuse series is available on Mouser, priced between $0.531 and $1.16, depending on the quantity. Similarly, the Nexperia NPS3102A and NPS3102B e-fuses can be found on Mouser for $1.93 each. The STMicro VNF9Q20F,also available on Mouser, is priced higher at approximately $5.34 for a single unit.
Debashis Das is a technical content writer and embedded engineer with over five years of experience in the industry. With expertise in Embedded C, PCB Design, and SEO optimization, he effectively blends difficult technical topics with clear communication
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