New electronic systems over-temperature detection ICs

Toshiba Electronics Europe GmbH has released two over-temperature detection ICs – the first in its Thermoflagger family. The devices can be combined with PTC thermistors to detect over-temperature conditions within electronic systems to take countermeasures if required. They are ideal for various applications, including mobile devices, home appliances and industrial equipment.

The devices provide a simple, inexpensive, low-current consumption solution that connects to several PTC thermistors. Extra over-temperature protection solutions can be realised by combining them with general temperature sensor ICs.

Two devices have been released. These are TCTH021BE, which provides a non-latching function for the FLAG signal when it detects abnormal states, and TCTH022BE, which offers a latching function for the signal.

The new products have a built-in current source and are utilised together with PTC thermistors, which greatly boost their ohmic resistance values once a certain temperature level has been exceeded. A rising temperature close to any PTC will cause the voltage to increase at the PTCO pin, activating the FLAG signal and detecting an over-temperature condition. By connecting numerous thermistors in series, over-temperature detection for multiple locations is readily possible.

The products are supplied in the small, standard SOT-553 package measuring only 1.6mm x 1.6mm x 0.55mm. They provide a low current consumption (IDD10U) of 11.3μA (typ), and the PTCO output current may be selected. Typically, IPTCO is 10μA with a strong accuracy of ±8%.

Operating supply voltage (VDD) may range from 1.7V to 5.5V, and the devices can function at temperatures between -40C to +125C.

These products enable users to configure over-temperature detection for a complete electronic device easily without greatly impacting the size and power consumption of the device.