Safe Heating Circuit and Electric Blanket Provided with Safe Heating Circuit

Abstract

A safe heating circuit, including: a PTC electric heating element, generating heat when being electrified; a first switching element, coupled into a ground loop of the PTC electric heating element and configured to switch on or off a power loop of the PTC electric heating element based on an on-off control signal; a first voltage acquisition circuit, configured to sample a first temperature voltage based on a ground current of the PTC electric heating element; an NTC element, disposed between the PTC electric heating element and a sensing element; the sensing element, configured to receive a leakage current from the PTC electric heating element transmitted by the NTC element; a second voltage acquisition circuit, configured to sample a second temperature voltage based on the leakage current; and a controller, configured to compare the first temperature voltage or the second temperature voltage to a set temperature voltage and output the on-off control signal based on a comparison result.The safe heating circuit of the present invention can precisely control the heating temperature, and timely detect a fault and switch off a power supply to ensure the safety of a user.

Dependencies are inferred from the claim text.