Background
Conventional pulse-width modulation (PWM) control techniques such as voltage-mode DC-DC converters are susceptible to single event effects (SEE) of radiation in harsh environments due to their inherent analog nature. Digital controllers, on the other hand, are more immune to SEEs than their voltage-mode analog counterparts. Current-mode converters yield better transient response with simpler frequency compensation as compared to voltage-mode converters. However, analog and digital controllers fabricated on widely available Bi-CMOS processes are unable to mitigate the effects of radiation-induced errors.
Time-domain controllers offer benefits of both analog and digital controllers by using time as a processing variable. This approach eliminates the need for a wide-bandwidth error amplifier and PWM comparators used in analog controllers or high-resolution converters used in digital controllers, thus resulting in reduced power consumption and silicon area while being easily scalable to advanced process nodes.
Invention Description
Researchers at Arizona State University and NASA have developed an intermediate bus converter for aerospace applications that uses an adaptive time-domain controller. The controller used in this technology enables constant on-time control for buck converter, and peak-current, constant off-time control for boost converter. The controller uses quasi-constant switching frequency and a bandgap reference with triple redundancy and scaling for radiation protection.
Potential Applications
- Intermediate power bus for space applications:
- Communications
- Control & navigation
- Sensing
Benefits and Advantages
- Programmable (replaces original 1970s analog technologies)
- High reliability and performance
- 5x reduction in size, weight, and power (SWAP) requirements
- Low cost for development
- Scalable to adapt to any power supply design