A temperature control device comprises: an operation amount upper limit setting part that sets an upper limit of an operation amount of a heater; and a temperature change rate comparing part that determines, in every prescribed time period, whether an actual measured change rate of the temperature of a body-to-be-heated with respect to time is outside a prescribed range that includes a target rate of change. The operation amount upper limit setting part sets the upper limit to a preset initial value when operation of the heater is started toward the target temperature, and updates the upper limit, in a period until the temperature of the body-to-be-heated reaches the target temperature, such that the difference between an actual measured temperature and a temperature locus that is represented using the target rate of change becomes smaller when it is determined that the actual measured change rate is outside the prescribed range.

A thermal system includes a two-wire heater and a power switch. The power switch is to provide power to the two-wire heater from a power source based on a control signal. The thermal system includes a controller having a sensor circuit configured to measure an electrical characteristic of the two-wire heater. The controller is to calculate a temperature of the thermal system based on a change in the measured electrical characteristic and determine whether the temperature is greater than a temperature setpoint. The controller is to output the control signal based on the determination.

A current sensing circuit includes a first field-effect transistor (FET) coupled to a first current source, an inductor, and a power FET, and includes a second FET coupled to a second current source. The current sensing circuit also includes a temperature circuit coupled to the first FET and the second FET. The temperature circuit is configured to compensate for one or more differences between one or more temperature coefficients of one or more of the first FET, the second FET, and the power FET.

A current sensing circuit includes a first field-effect transistor (FET) coupled to a first current source, an inductor, and a power FET, and includes a second FET coupled to a second current source. The current sensing circuit also includes a temperature circuit coupled to the first FET and the second FET. The temperature circuit is configured to compensate for one or more differences between one or more temperature coefficients of one or more of the first FET, the second FET, and the power FET.