Temperature indicators protect USB Type C and USB PD cables
Littelfuse expands its PolySwitch setP series of digital temperature indicators, introducing the SETP0805-100-CC which is designed to protect USB Type‑C and USB power delivery charging cables from overheating. It is optimised for use in cables equipped with USB Type-C connectors at both ends.
Typical applications for SETP0805-100-CC temperature indicators include consumer electronics, primarily for mobile and wearable devices equipped with USB Type-C cables (with a Type-C plug on each end) and USB Type-C chargers (such as cables fixed or captive to a charger for laptops).
When dust, dirt, or other debris is trapped in a USB Type-C cable connector or the connector has deformed pins, it creates a resistive fault from the power line to ground, which can cause a dangerous temperature rise without increasing the current. When the temperature reaches the setP’s indicating temperature (100 degrees C), the setP switches from low resistance to very high resistance, shutting down the flow of power. Once the user disconnects the cable and removes the debris, the cable can resume normal operation.
The compact 0805 footprint of Littelfuse’s setP temperature indicators makes them at least 50 per cent smaller than other versions that require placing a device on the power line, claims Littelfuse. The setP devices can be used to protect cables designed for 100 W of power or more.
The number of consumer electronics, wireless, and computing devices equipped with USB Type-C connectors sold each year is estimated to reach 5bn by 2021. This is expected to spur demand for products that can protect cables and connectors from overheating damage. The SETP0805-100-CC temperature indicators are claimed to offer the smallest, most energy-efficient solution available today to protect people and electronics against overheating.
The setP temperature indicators have a rigid structure which is compatible with conventional assembly and moulding operations used in cable and connector manufacturing. They are independent of power simplifies part selection to protect systems that operate at 100 W of power or more.
The setP indicator is an easy drop-in replacement for over-temperature protection to existing designs as there is no disruption of the communication channel, reports Littelfuse.
The original (single-end) setP series digital temperature indicator (part number SETP0805-100-SE) and the SETP0805-100-CC are available as surface mount devices in tape and reel packaging. Sample requests may be placed through authorised Littelfuse distributors worldwide.