Battery-Based Power Supplies - CEDRAT TECHNOLOGIES - #1

Text version of the page

CEDRAT GROUPE www.cedrat.com Battery-Based Power Supplies Battery-based power supplies can be used in a broad range of applications for different reasons. From the customer needing low noise power supplies for sensing equipment, to the customer willing to drive a magneto or piezo-mechanism from an autonomous power supply in embedded applications, Cedrat Technologies can design power supplies using high quality lithium-polymer batteries. Objective The use of battery-based power supplies is a smart solution to solve issues such as the need for: • Systems with autonomous energy source • High power density and efficiency • Reduced size and weight • Low noise • Specific supply voltages The targeted applications are mainly the embedded applications, where it is mandatory to have autonomous power supplies. Low power voltage levels can be provided to supply a low-power board such as a conditioning electronic or a digital controller. High power voltage levels can also be provided if it is required to supply a power amplifier for a piezo-actuator for instance. For noise sensitive electronics and components, it is also interesting to use battery-based power supplies which allow avoiding the noise carried by the power grid. For instance, this is used for high resolution and precision sensing equipments such as accelerometers, 3-D localizing in medical environment. Technology The power supplies are based on 3.7V (typical) lithium-polymer cells which provide an unregulated output voltage, those batteries correspond to the energy storage of the supply. The lithiumpolymer technology is the most efficient battery technology; it is able to provide high power in a reduced package and for a reduced weight. The cells can be arranged in serial or parallel depending on the need for voltage, current, and operation time. This allows fitting easily with the customer’s needs, simply by changing the cells configuration. The supply features a smart charge circuit for the lithium polymer battery cells, which protects the battery cells from overload and over-temperature during charge sequence. The charging circuit is able to operate from a simple AC/DC converter connected to the grid. The regulated voltage levels are generated from the battery power source using DC/DC converters, which can decrease, elevate, or invert the input voltage from the batteries. This means that almost any output voltage can be built from the battery source, using those specific topologies. The DC/DC converters exhibit very high efficiency of more than 80% in 3.7V, 2000mAh, lithium-polymer battery cell. Synchronized DC/DC converters for generating different voltage levels from a battery source.