By Frederik Dostal, field applications engineer, Analog Devices.
Conversion efficiency is a key characteristic of power converters. Common switching regulators for step-down conversion (buck converters) typically have conversion efficiencies of between 85% and 95%. The efficiency to be reached strongly depends on the available supply voltage and the respective output voltage to be generated, as well as the required load current. However, numerous applications require a special type of conversion efficiency for which there are special switching regulator solutions. These deployments require optimised converters for low output power.
Battery-operated systems that are always on often need to consume a very low amount of current in standby mode. Examples include sensors that measure vibrations in bridges or that detect forest fires. In these cases, it is important to have a low battery discharge over long periods of time. This property is particularly important in systems that depend on energy harvesters as energy sources.
Such sensors are frequently also connected via radio to other devices. Individual node points that are usually supplied through energy harvesting or with batteries are linked to transmit signals across several node points and over long distances. These individual radio nodes must always listen for signals in a type of ‘sleep mode’ and then, when a corresponding signal occurs, switch to an operating mode with a higher energy consumption and propagate the corresponding signals.
A new class of DC-to-DC converters has been introduced with the LTC3336. While the output voltage is generated and there is a low load at the output, it only consumes about 65 nA of current in standby mode. Figure 2 shows a compact example circuit that generates an output voltage of 2,5 V from a VIN of approximately 7 V.
As is usual with such voltage converters, the output voltage is not set via a resistor voltage divider. This would waste too much energy. To allow different output voltages to be set, the pins OUT0 to OUT3 are used. Depending on the wiring of these pins, the output voltage can be set in steps between 1,2 V and 5 V.
In many energy harvesting applications, the energy source must be protected from excessive current loads. Some batteries or harvesters can only deliver a limited amount of current. If this specific current limit is exceeded, the voltage sags or, in some cases, damage can even occur. Therefore, it makes sense to limit the current draw of the power converter. The LTC3336 can limit the input current in adjustable steps between 10 mA and 300 mA. This input current limitation is similar to the output voltage in that it can be set through appropriate wiring of the IPK0 and IPK1 pins.
The efficiency plot in Figure 3 shows the efficiencies that can be reached with very low output currents such as 1 µA. A lot of energy is saved, especially in applications with long operating times and low loads.
Conclusion
The LTC3336 is the perfect choice for battery-powered systems since it draws only 65&nbs;nA of current when in standby mode. This means that circuits with fixed battery sizes can be operated for a much longer time, or energy harvesters can be designed to be smaller and therefore lower-cost.
High-precision current transducer
Power Electronics / Power Management
Danisense announces its new high-precision DP12IP current transducer designed for isolated DC and AC current measurement in demanding PCB-mounted power electronics applications.
Read more...Secure holder for protected 18650 batteries
Power Electronics / Power Management
Designed for protected 18650 batteries up to 70 mm long, the holder offers secure retention for portable, industrial, and embedded applications.
Read more...More room to scale Altron Arrow
Power Electronics / Power Management
With the latest STM32H5 lines from STMicroelectronics, you can now scale within the same platform, from a compact 1 Mbyte device to higher-memory MCUs for graphics-rich and feature-heavy designs.
Read more...Multi-constellation GNSS module in a legacy-compatible footprint Altron Arrow
Telecoms, Datacoms, Wireless, IoT
Telit Cinterion has announced the SE869eK2L, a single-frequency L1 GNSS module designed to help device manufacturers upgrade legacy positioning designs with improved performance and cost efficiency, while preserving design continuity.
Read more...Compact SSI family for industrial automation Altron Arrow
Passive Components
Infineon Technologies has introduced the ISSI20BxxF Solid State Isolator (SSI) family, bringing solid-state isolation technology into high-volume applications traditionally served by photovoltaic isolators (PVIs), photovoltaic relays (PVRs), and electromechanical relays (EMRs).
Read more...Rev 2.0 PolarFire FPGA ethernet sensor bridge Altron Arrow
Computer/Embedded Technology
Smaller, multi-camera platform enables scalable Ethernet architectures for NVIDIA Edge AI systems, while lowering power, cost and integration complexity.
Read more...Surface mount power amplifier for high-power applications RF Design
Power Electronics / Power Management
The GNA-63-5W+, from Mini-Circuits, is a GaN MMIC Power Amplifier (PA) designed for demanding RF applications requiring high efficiency, excellent linearity, and a compact footprint.
Read more...1200 V QSiC modules
Power Electronics / Power Management
SemiQ Inc has launched the QSiC Dual3, a family of 1200 V half-bridge MOSFET modules for motor drives in data centre cooling systems, grid converters in energy storage systems, and industrial drivers.
Read more...Universal IR receiver module Altron Arrow
Telecoms, Datacoms, Wireless, IoT
Vishay Intertechnology has introduced a new series of infrared (IR) receiver modules for IR remote control applications, which feature a wide modulation frequency acceptance from 30 kHz to 68 kHz.
While every effort has been made to ensure the accuracy of the information contained herein, the publisher and its agents cannot be held responsible for any errors contained, or any loss incurred as a result. Articles published do not necessarily reflect the views of the publishers. The editor reserves the right to alter or cut copy. Articles submitted are deemed to have been cleared for publication. Advertisements and company contact details are published as provided by the advertiser. Technews Publishing (Pty) Ltd cannot be held responsible for the accuracy or veracity of supplied material.
printer friendly version
