Method and control structure for a sensor heater
AssigneeDelphi Technologies, Inc.
InventorsJames W. Streit, Dale M. Harris
Life of this patent
Estimating the term…
Abstract
A control structure and method for controlling a sensor heater including a power supply connected to a switching device for pulse width modulating a voltage from the power supply. The switching device is further connected to a resistance heater. A microcontroller having a single output is connected to the switching device and a single input from the microcontroller is connected to a high side of the resistance heater. The microcontroller determines a pulse width modulation duty cycle to maintain a constant power dissipation of the resistance heater.
Claims9
A method of controlling a sensor heater comprising the steps of:
- a) providing a microcontroller for adjusting a pulse width modulation duty cycle of a heater;
- b) measuring a peak voltage across the heater;
- c) determining a pulse width modulation duty cycle according to the equation:
- duty cycle=Ton/Tcycle=Vrms2/Vpeak2 where Ton is the time of the duty cycle when voltage is being transmitted to a heater and Tcycle is the total time of the duty cycle, and Vrms is a constant desired voltage and Vpeak is a voltage that is measured on the high side of the heater;
- d) transmitting the pulse width modulation duty cycle to the heater for maintaining a constant power dissipation of the heater.
A control structure for a sensor heater comprising:
- a power supply connected to a switching device for pulse width modulating a voltage from the power supply, the switching device further connected to a resistance heater;
- a microcontroller having a single output connected to the switching device and a single input connected to a high side of the resistance heater, the microcontroller determining a pulse width modulation duty cycle to maintain a constant power dissipation of the resistance heater.
Dependencies are inferred from the claim text.