Supporting your IoT system construction
Key person interview
Ricoh has been leading the CMOS power supply technology in the world. It is one of the world‘s largest producers of power management ICs for mobile phone applications. With the emergence of the Internet of Things, IoT, how does Ricoh capture IoT? What sort of vision and answer does Ricoh have to prepare for the future expansion of the IoT market? We have asked Mr. Takahashi, a key person to the IoT strategy of Ricoh.
Please tell us about Ricoh's concept on Internet of Thing (IoT).
We see IoT as a possible way to resolve the social challenge where all sorts of "things" are connected to the Internet, particularly where sensing devices are exploding.
What made Ricoh to concentrate on the IoT market?
We have a corporate philosophy, "To create new value with analog IC and contribute to eco-friendly social growth." We thought our analog power supply technology, which has been cultivated over the years, helps to achieve challenges on IoT market such as autonomous power supply, extended-life power supply, and sensing accuracy. This concept is settled after various discussion.
What are the technical challenges of IoT system?
The amount of data becomes enormous as sensing devices increase, and a load to the network is the major challenge. The security of the information gained from sensing devices and the communication distance of sensing devices are additional issues.
Future IoT trends and solutions to challenges
What are the solutions to the challenges for IoT system?
There are two future IoT trends. First trend is the Artificial Intelligence (AI) will be built inside of IoT devices, and it enables required data be sorted and encrypted. The second trend is the change of the communication method for extending communication distance. Although it is hardly conceivable before, "The power supply capable of flowing large current while having ultra-low supply current" will be necessary. Ricoh will respond to these trends promptly and have an appropriate lineup available.
What are the features of the "power supply capable of flowing large current while having ultra-low supply current" ?
IoT devices do not always operate, they often operate intermittently. As for intermittent operation, having ultra-low supply current is necessary since the current at standby mode is an important element to determine a battery life. On the other hand, the large current is temporarily needed in order to sort/encrypt data and extend communication distance as an active operation. For example, the only 1 µA increase of current at standby mode of the IoT device that operates by 1 A within 5 ms once an hour shortens the battery life of device by half.
Ricoh offers lineups of DCDC converters that ensure important characteristics of power management IC including output voltage accuracy and output response while suppressing the supply current. The buck-boost converter RP604 suppresses the supply current to about 1/90, from 27.5 µA to 0.3 µA, comparing it with our conventional products. The buck converter R1800 for photovoltaic suppresses the supply current to 144 nA. Both of them have one of the top characteristics in the industry (Researched by Ricoh as of December 2017).
How did you manage to suppress the supply current while having the output characteristics ensured?
We can't mention too much details because it is our core technology, but using our original merged process and circuit design technology, we were able to reduce the supply current while maintaining the output voltage accuracy and the output response characteristics. You can experience this effect very well by using our products.
With these technologies, what are the benefits does the chipset vendor can get?
There are two major benefits; the first benefit achieves battery-less and maintenance-free IoT devices. The second benefit is the miniaturization of harvester and battery due to the ultra-low supply current of power management IC. IoT devices are miniaturized thereby.
Last but not least, tell us Ricoh's future prospects and resolutions.
The main line of our business is power management ICs, but we will continue to collaborate and propose total solutions with manufacturers of harvesters, secondary cells, sensors, microcomputers, and communication ICs.
Please look forward to our power management ICs for IoT market and our solutions.
The RP604 is a buck-boost DCDC converter IC for IoT devices that achieves ultra-low quiescent current and miniaturization. Input voltage: 1.8 V to 5.5 V, output voltage: 1.6 V to 5.2 V, and maximum output current: 300 mA at buck.
Since it is a buck-boost type, the boost operation enables the continuous battery use even if a battery voltage drops below the system use voltage. The flatted output voltage prevents instantaneous stop of system devices by facilitating a system design and supporting a rapid power voltage drop.
|RP511||Low Quiescent Current Buck DCDC Converter with Synchronous Rectifier||300 nA||100 mA||2.0 V to 5.0 V|
|RP512||Low Quiescent Current Buck DCDC Converter with Synchronous Rectifier||300 nA||300 mA||2.0 V to 5.0 V|
|RP604||Low Quiescent Current Buck-Boost DCDC Converter with Synchronous Rectifier||300 nA||300 mA||1.8 V to 5.5 V|
|RP118||Low Supply Current Voltage Regulator (LDO Regulator)||200 nA||100 mA||1.7 V to 5.5 V|
IQ: Operating Quiescent Current
The RP122, a low-noise LDO regulator, offers low output noise of 8 µVrms (10 to 100 kHz). It is capable of handling analog signal without deteriorating the accuracy of 16-bit ADC/DAC. It also achieves a high ripple rejection of 90 dB@1 kHz, 85 dB@10 kHz, and 65 dB@100 kHz. It allows designing IoT devices without being concerned with noise since it reduces noise even if it is used for post-switching regulator.
The R1800 is a power-storing buck DCDC converter for a photovoltaic and vibration energy harvester. It achieves a minimum starting power of 720 nW, one of the top electromotive force level in the industry, while having an ultra-low quiescent current of 144 nA (Typ.) at no load and normal temperature. It also provides a high efficiency of 90% at a light load with 10 µA output current. The maximum power control, which utilizes the harvester capability, optimizes a power supply from an energy harvester. The reverse current protection provides highly efficient power extraction with the lossless charge saved in the power storage element even if there is no supply of power from the energy harvester.
*1: Researched by Ricoh as of December 2017.
|Product Name||Function||IQ||IOUT||VIN||Minimum Starting Power|
|R1800||Low Quiescent Current Buck DCDC Converter for Energy Harvester||144 nA||1 mA||2.0 V to 5.5 V||0.72 µW|
IQ: Operating Quiescent Current