Patent ID: 8075178

Claim:
Circuitry for the adjustment and calibration of a heating element and an ambient temperature sensor, comprising: a) an amplifier having a positive input, a negative input, and an output; b) one or more heating metal oxide semiconductor (MOS) transistors selectably coupled in parallel and having a heating transistor gate, a heating transistor source, and a heating transistor drain, wherein: 1) the heating transistor drain is coupled to the positive input of the amplifier; and 2) the heating transistor source is configured to receive a supply voltage; 3) the heating transistor gate is coupled to the amplifier output; c) one or more ambient MOS transistors selectably coupled in parallel and having an ambient transistor gate, an ambient transistor source, and an ambient transistor drain, wherein: 1) the ambient transistor gate is coupled to the amplifier output; and 2) the ambient transistor source is configured to receive the supply voltage; and d) a temperature difference resistance configured: 1) to be coupled at least partially between an ambient connection and the ambient transistor drain; and 2) to be coupled at least partially between the ambient connection and the negative input of the amplifier.