With this in mind scientists have recently presented a new power converter that maintains its efficiency at currents ranging from 500 picoamps to 1 milliamp. This is significant since it represents a 200,000-fold increase in operating current levels. With electronics, power conversion refers to converting electric energy from one form to another such as converting between AC and DC; or just changing the voltage or frequency; or some combination of these.
The Internet of Things covers a vast spectrum, from vehicles, appliances, civil structures, manufacturing equipment, and life in home, being equipped with sensors designed to report information to networked servers. This aids the coordination of tasks.
For these sensors to work effectively they need to function at low power in order to conserve battery life. To do this the sensors are required to draw upon a wide range of electrical currents. Sometimes an operation will require a low current, such a taking a simple measurement; whereas at other times a sensor requires a high level of current, such as when transmitting to a radio receiver located some distance away.
Most power converters are efficient only within a narrow range of currents, which limits the effectiveness of sensors and could potentially delay developments with connected devices. To overcome this MIT’s Microsystems Technologies Laboratories has proposed a new power converter. The convertor can maintain its efficiency at currents ranging from 500 picoamps to 1 milliamp.
Discussing this in a university research brief, principal scientist Arun Paidimarri explains: “Typically, converters have a quiescent power, which is the power that they consume even when they’re not providing any current to the load.”
He adds: “So, for example, if the quiescent power is a microamp, then even if the load pulls only a nanoamp, it’s still going to consume a microamp of current. My converter is something that can maintain efficiency over a wide range of currents.”
The type of convertor is what is known as a step-down converter. This means the output voltage is lower than its input voltage. For example, it takes input voltages ranging from 1.2 to 3.3 volts and reduces them to between 0.7 and 0.9 volts. This happens due to packets of energy, analogous to a switch being turned on and off.
The new convertor contains a variable clock. This device can run the switch controllers at a wide range of rates. This results in a 50 percent reduction in power compared with previously reported experimental low-power, step-down converters.
