COLUMN Vol.1 Do you know what it is? It is the secret to dramatically extending the battery life of wearable devices! (3)

Technology innovation

In the area of ultra-low energy consumption such as wearable devices, the self-current consumption of switching regulator circuits on their own causes a reduction in power efficiency. When the output load is light, the self-current consumption of switching regulators becomes relatively large, and this reduces the efficiency.

In order to resolve this issue, ABLIC set a target for the self-current consumption of these switching regulators at 260nA (nanoampere) and advanced the development. Based on these innovative technologies, SII has completed the S-85S1A and the S-85S1P series. Among the innovative technologies adopted for the S-85S1A/S-85S1P, lets introduce three remarkable attributes.

(1) Innovative control topology
The target of self-current consumption of 260 nA cannot be reached by extending the existing technology. Accordingly, in developing the S-85S1A/S-85S1P, the foundation of control topology was reviewed. Specifically, ABLIC developed its own COT (Constant On-Time) control technology and created the S-85S1A/S-85S1P Series centered on this technology. The COT control also enables a fast transient response to load fluctuations.

Figure: Comparison of transient response efficiency between the S-85S1A, which utilizes the COT control method, and conventional products

(2) Low power technology that has been demonstrated in IC design achievements from
ABLIC have been accepted in the low power semiconductor market for a long time. SII has established a manufacturing process suited to operating currents in the nanoampere order. This experience was fully utilized for downsizing and reducing the power consumption of the S-85S1A/S-85S1P.

Figure: Quiescent current consumption of S-85S1A and S-85S1P

(3) Adaptation of power gating technology for analog circuits.
The power gating technology used for logic circuits is adopted for analog circuits as well. This is a mechanism that applies the current to circuits only when they are used. Conventional analog circuits have had challenges in that stable control of load current demands are difficult and reducing the IC's self-current consumption is prone to cause a slow response. For the circuits of the S-85S1A/S-85S1P, many advancements have been implemented to solve these challenges.

The industry's smallest class of IC packaging

The S-85S1A/S-85S1P use the industry proven SNT packages from SII. The SNT-6A & SNT-8A are ultra-small outline non-leaded thin packages with an established reputation. It is optimized for use by devices that have many restrictions in terms of space, such as wearable devices. In addition, a variety of protective functions are included within these IC's reducing the need for numerous external components.

Figure: Space-saving implementation of S-85S1A

There are other competitive products that claim to have a self-current consumption of the nanoampere order. However, there are practically no products worldwide that are able to match the level of performance and functionality of the S-85S1A/S-85S1P. These new products have taken the lead over their competitors.

Many customers have already reacted and applications for a wide range of end products, beyond wearable devices, are utilizing these new IC's.

• Wearable Devices
• Bluetooth Devices
• Wireless Sensors
• Healthcare Products
• Smart Meters
• Handheld Game Consoles
• IoT for Household, Automobiles and Industrial

ABLIC will continue to expand the lineup of the S-85S1 Series since the basic circuit can support a high output current such as 2A. Variations will be added. The development of products that support higher input voltages are also under consideration.