With the rapid development of technology, smart rings, as an emerging smart wearable device, have drawn increasing attention from brand manufacturers. Chinese wearable manufacturer Huami released a new smart ring called Helio Ring during CES 2024. Samsung Electronics officially released the Galaxy Ring in July 2024, which received a warm response from the market.The smart ring not only has the fashion attribute of decorative trendy products, but also serves as an auxiliary intelligent sensing accessory for smartphones, used for monitoring human health data. Compared with watches and bracelets, the ring closer to the skin, so it has an accuracy advantage in collecting basic human biological information such as the rhythm of the pulse, heart rate, blood oxygen, electrocardiogram, and body temperature, etc. Compared with smart watches, the ring also has the characteristic of wearing without feeling, which can better meet the differentiated needs of users.The smart ring is limited by space size, and the equipped lithium battery capacity is usually between 15mAh and 23mAh, and the battery life needs to reach 5 days or longer. Therefore, chips with ultra-low power consumption and ultra-small size are bound to be favored by product developers. Cellwise has launched multiple ultra-low power small-sized power chips. As shown in Figure 1, which are very suitable for smart ring applications. Linear Charger-CW6308/CW6305/CW6307The CW6308 is the linear charger with the smallest size in the industry that supports the I2C interface and power path management. It supports a maximum charging current of 320mA. The CW6308 could extend the battery life with its ultra low power consumption. After only being powered by the battery and enabling the Watchdog function, the chip has only 5μA quiescent current in normal mode and 500nA in ultra-low power mode. In ship mode, the IC only consumes 300nA. The CW6305 and CW6307 has the similar features as the CW6308，but both support maximum charging current of 470mA. The CW6308 is available in lead-free 0.4mm pitch, 1.25mm x 1.25mm, 9-ball WLCSP package. The CW6305 and CW6307 are available in lead-free 0.5mm pitch, 1.55mm x 1.55mm, 9-ball WLCSP package.Fuel Gauge-CW2215The CW2215 is a single-cell lithium battery fuel gauge with the industry's lowest power consumption of 5μA. It has a high-precision ADC for voltage, current and temperature detection. The chip has a built-in "FastCali" algorithm. Combined with the battery characteristic parameters from the Battery Characterization, it can accurately calculate the remaining capacity (SOC), cycle count (Cycle) and battery health (SOH), and can be configured to report interrupts in case of low power, high temperature or low temperature. The IC is available in Lead-free 0.5mm pitch, 1.58mmx1.53mm, 9-ball WLCSP package.Low-Dropout Linear Regulator-CW6004The CW6004 is a 200mA ultra-low quiescent current LDO. The quiescent current is as low as 300nA. The input voltage ranges from 1.6V to 5.5V. The output voltage is selectable from 1.1V, 1.2V, 1.5V, 1.8V, 2.5V, 2.8V, 3.0V and 3.3V. The CW6004 has a fast response to ensure the stability of the output voltage when the device quickly switches from standby and light load to heavy load. The IC is available in DFN-4, 1.0mm x 1.0mm package.Figure 2.  CW6004 Quiescent Current vs Input VoltageFigure 3.  CW6004 Ground Current vs. Output CurrentBuck Converter-CW6602/CW6603The CW6602 is an ultra-low quiescent current buck converter with an input voltage range from 2.15V to 5.5V and 8 selectable voltage outputs range from 1.2V to 3.3V. The quiescent current is as low as 330nA, and its load current is 0.6A Max. When the output voltage is 1.8V, the heavy load efficiency of the chip is over 90%, and the light load efficiency of 100μA can also reach 85%. The chip has a fast load dynamic response capability. The device is available in a tiny lead-free 0.4mm pitch,1.575mm x 0.825mm, 8 ball WLCSP package.CW6603 has the same functions and package size as the CW6602. The difference is that the output voltage range is 0.6V to 1.2V.Figure 4.  CW6602 Vout=1.8V EfficiencyLoad Switch-CW3301The CW3301 is a load switch with an ultra-low MOS on-resistance and maximum current up to 2.0A with input voltage range from 1.1V to 5.5V. The output voltage slew rate of the chip is controlled to effectively protect the subsequent chips. It has an industry-leading 5nA on-state quiescent current and a 12nA off-state leakage current. It supports optional fast output discharge. The IC is available in a tiny lead-free 0.4mm pitch, 0.76mm x 0.76mm, 4-ball WLCSP package.Battery Protection IC-CW1011The CW1011 is single-cell lithium battery protection chip that supports high-precision overvoltage, undervoltage, charge overcurrent, discharge overcurrent and short circuit protection. The chip integrates dual MOSFETs with an on-resistance of 54 mohm internally. The quiescent current is 2.5μA and it supports sleep mode with a power consumption as low as 20nA. The IC is available in tiny DFN-6L, 1.5mm x 2.0mm package.Cellwise has been deeply engaged in ultra-low power consumption technology for many years and has numerous design wins in wearable devices and digital accessories such as smart watches, TWS earphones, active styluses, and wireless Bluetooth keyboards and mouses. The power IC introduced today will definitely help brand manufacturers and solution developers achieve smaller space stacking, longer battery life, and better user experience for smart rings.Thank you for your continued attention to Cellwise and our products.

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There are CellWise Protection ICs inside 30 million Li-ion Battery Packs!     About CellWiseCellWise Microelectronics Co., Ltd. is a leading fabless IC provider of power and battery management devices.We provide our customers with safe, green, high efficient and low cost electric power supply and energy storage solutions. Major product lines are including Battery management system IC, Fuel-Gauge IC, Li-ion battery protection IC, Power management IC, Charge Management IC, USB Charge Controller IC. We have branch offices in Shanghai,Shenzhen,Dongguan to provide battery testing,sells and marketing and high efficient technical support services.

CW1013 series is a protection IC for lithium-ion / lithium polymer rechargeable batteries, which includes high-accuracy voltage detection circuits and delay circuits. It is suitable for protecting 1-cell lithium-ion / lithium polymer rechargeable battery packs from overcharge, overdischarge, and overcurrent. By using an external overcurrent detection resistor, it realizes high accuracy overcurrent protection with less effect from temperature change. Features • Overcharge Detection Voltage      • Range 4.225V~4.600V, Accuracy ± 15mV • Overdischarge Detection Voltage      • Range 2.000V~3.500V, Accuracy ± 40mV • High-accuracy Overcurrent Detection      • Discharge Overcurrent Detection Voltage 1, Accuracy ± 1.0mV      • Discharge Overcurrent Detection Voltage 2, Accuracy ± 1.0mV      • Load Short-circuiting Detection Voltage, Accuracy ± 5.0mV      • Charge Overcurrent Detection Voltage, Accuracy ± 1.0mV • Detection Delay Times Are Generated only by Internal Circuits • VM Pin and CO Pin Can Withstand Max.28V • 0V Battery Charge: Inhibited or Allowed • Low Current Consumption : 2.28uA Typ. • Package ：DFN-6(1.57mmx1.90mmx0.45mm)   Application Field •  Lithium-ion Rechargeable Battery Pack • Lithium Polymer Rechargeable Battery Pack Application Circuits

The CW6601 is a high efficiency synchronous step-down converter with ultra-low quiescent current of typ. 120nA. The device is optimized to operate with a 2.2μH inductor and 10μF output capacitor and its typical switching frequency is 1.0MHz. It provides high efficiency at light load down to 10μA. The CW6601 input voltage range is from 2.5V to 5.5V and it has eight programmable output voltage from 1.2V to 3.3V while delivering output current up to 300mA. The device is available in a tiny lead-free 0.4mm pitch, 1.575mmx0.825mm, WLCSP-8 package.   Features     • Input Voltage Range: 2.5V to 5.5V • Programmable Output Voltage:   • 8 Options from 1.2V to 3.3V • Output Current up to 600mA, Peak to 1A • Typical 330nA Quiescent Current • Up to 90% Efficiency at 10µA Output Current • Low Output Voltage Ripple • Output Voltage Discharge • Automatic Transition to 100% Duty Cycle • Over Current Protection • Lead-free WLCSP-8 Package         Application Circuits  

The CW6601 is a high efficiency synchronous step-down converter with ultra-low quiescent current of typ. 120nA. The device is optimized to operate with a 2.2μH inductor and 10μF output capacitor and its typical switching frequency is 1.0MHz. It provides high efficiency at light load down to 10μA. The CW6601 input voltage range is from 2.5V to 5.5V and it has eight programmable output voltage from 1.2V to 3.3V while delivering output current up to 300mA. The device is available in a tiny lead-free 0.4mm pitch, 1.575mmx0.825mm, WLCSP-8 package.   Features     • Input Voltage Range: 2.5V to 5.5V • Programmable Output Voltage:   • 8 Options from 1.2V to 3.3V • Output Current up to 300mA • Typical 120nA Operational Quiescent Current • Up to 95% Efficiency • Low Output Voltage Ripple • Output Voltage Discharge • Over Current Protection • Lead-free WLCSP-8 Package         Application Circuits  

The CW6308 is a high accuracy linear charger IC with power path management for Wearables and IoT devices using single-cell Li-ion/Li-Polymer batteries. The device embeds a charge management block and fulfills full charge phases, including pre-charge, fast charge constant current (CC), fast charge constant voltage (CV) and charge termination. The device integrates power path management (PPM) that allows the device to provide power for the system running while charging the battery even with a depleted battery. It also supports full system reset and ship mode. The CW6308 provides system over current protection (OCP) by limiting the current from the input to the system and that from the battery to the system. The battery to system discharging path will be cut off when battery voltage is lower than the battery under voltage lockout (UVLO) threshold. The CW6308 could monitor the battery pack temperature via the NTC pin (10K or 100K NTC thermistor supported) and suspend charging once the battery is in hot or cold condition. The device also integrates charge safety timer and pre-charge timer. The ongoing charge will be turned off when either of the two is expired. An I2C control interface allows the host to configure charger parameters and also get the IC status. I2C watchdog is available during charge and discharge. The device is available in a tiny lead-free 0.4mm pitch, 1.25mm x 1.25mm, 9-ball WLCSP package.   Features     • Linear Charger for 1S Li-ion/Li-Polymer Batteries   • +16V Maximum Voltage for Input Source   • Configurable 3.85V-4.6V CV Regulation   • ±0.5% CV Regulation Accuracy   • Configurable 10mA-320mA CC Charging   • Down to 1mA Termination Current • Power Path Management   • System Reset and Ship Mode Supported   • Battery Supplement Mode Supported • Configurable Input Voltage Regulation and Input Current Limit up to 500mA • NTC Thermistor Monitor Supported • OCP in Discharge and Supplement Mode • Charge Safety Timer and Pre-charge Timer • Watchdog during Charge and Discharge • Ultra-Low Battery Quiescent Current:   • 5µA in Normal Mode   • 500nA in Ultra Low Power Mode   • 300nA in Ship Mode • I2C Serial Interface • Lead-free 1.25mmx1.25mm, WLCSP-9 package         Application Circuits  

The CW6307 is a high accuracy linear charger IC with power path management for Wearables and IoT devices using single-cell Li-ion/Li-Polymer batteries. The device embeds a charge management block and fulfills full charge phases, including pre-charge, fast charge constant current (CC), fast charge constant voltage (CV) and charge termination. The device integrates power path management(PPM) that allows the device to provide power for the system running while charging the battery even with a depleted battery. It also supports full system reset and ship mode. The CW6307 provides system over current protection (OCP) by limiting the current from the input to the system and that from the battery to the system. The battery to system discharging path will be cut off when battery voltage is lower than the battery under voltage lockout (UVLO) threshold. The CW6307 could monitor the battery pack temperature via the NTC pin (10K or 100K NTC thermistor supported) and suspend charging once the battery is in hot or cold condition. The device also integrates charge safety timer and pre-charge timer. The ongoing charge will be turned off when either of the two is expired. An I2C control interface allows the host to configure charger parameters and also get the IC status. I2C watchdog is available during charge and discharge. The device is available in a tiny lead-free 0.5mm pitch, 1.55mm x 1.55mm, 9-ball WLCSP package.   Features     • Linear Charger for 1S Li-ion/Li-Polymer Batteries   • +28V Maximum Voltage for Input Source   • Configurable 3.85V-4.6V CV Regulation   • ±0.5% CV Regulation Accuracy   • Configurable 10mA-470mA CC Charging   • Down to 1mA Termination Current • Power Path Management   • System Reset and Ship Mode Supported   • Battery Supplement Mode Supported • Configurable Input Voltage Regulation and Input Current Limit up to 500mA • NTC Thermistor Monitor Supported • OCP in Discharge and Supplement Mode • Charge Safety Timer and Pre-charge Timer • Watchdog during Charge and Discharge • Ultra-Low Battery Quiescent Current:   • 5µA in Normal Mode   • 500nA in Ultra Low Power Mode   • 300nA in Ship Mode • I2C Serial Interface • Lead-free, 1.55mmx1.55mm WLCSP-9 package         Application Circuits  

CW5053 is BDC Motor controll IC which provides PWM motor driver, voltage, current and temperature protections, also supports LED lighting and battery gauge.Features    • BDC Motor Controller with MOSFET Pre-driver    • Input Voltage Range: 5.5V to 42V    • Supports 3/4/5s Li-ion Battery Cells     • Supports up to 10s Cells with External Resistor Divider    • Motor Over Current Protection:         • 3 Over Current Settings with Configurable Threshold and Delay         • “True Motor Current” Technique Compensates PWM Duty-cycle Effects     • Short Circuit Protection         • Threshold from 40mV to 240mV     • Battery Over Discharge Protection:         • Threshold From 1.9V to 3.16V     • Battery High/Low Temperature Protection     • Motor Over Temperature Protection     • BDC Motor Control:          • PWM Duty-cycle Control with Digital Deglitch and Soft Start         • 12V MOSFET Pre-drive    • NTC Based Over Temperature Protection    • Lighting LED Driver with Alarm Indication     • 3-LEDs Battery Gas Gauge     Application Circuits

CW1353 is 4~5 cells protection IC which provides voltage, current，open wire and temperature protection and cell balancing.Description• Overcharge protection      • Threshold 3.750V, and 4.175V ~4.450V,   25mV steps,  ±25mV accuracy• Over discharge protection      • Threshold from 2.100V to 3.000V,   100mV steps,   ±30mV accuracy• Excess discharge current protection      • Excess discharge current 1            • Threshold from 0.050V to 0.100V,   50mV steps,  ±5mV  accuracy      • Excess discharge current 2            • Threshold from 0.100V to 0.200V,    100mV steps,  ±10mV  accuracy      • Short circuits protection            • Threshold from 0.200V to 0.500V,   100mV steps,   ±20mV  accuracy• Flexible temperature protection threshold (Set up by external resistor)      • Charging over&under temperature protection      • Discharging over temperature protection      • Discharging under temperature protection(optional)• Cell balancing function• SEL pin to choose 4 or 5 series battery• Open wire detection• Load detection• PWM control discharge MOSFET• Ultra low power dissipation      • Normal working 15μA  (25°C)      • Sleep mode 5μA   (25°C)• Package type: SOP16Application Field• Power tools• E-bike• Vacuum cleaner• Other Lithium-ion or Lithium polymer battery packsApplication Circuits

CW1274 is 4~7 cells protection IC which supports cascading and also prorivdes full protection and balancing features.Features• Overcharge protection      • Threshold 3.650V, 3.850V,and 4.175V ~4.375V,   25mV steps,  ±25mV accuracy• Over discharge protection      • Threshold from 2.300V to 2.800V,   100mV steps,   ±30mV accuracy• Excess discharge current protection      • Excess discharge current 1            • Threshold from 0.050V to 0.100V,   ±5mV  accuracy      • Excess discharge current 2            • Threshold from 0.100V to 0.200V,    ±10mV  accuracy      • Short circuits protection            • Threshold from 0.200V to 0.500V,    ±20mV  accuracy      • Excess charge current protection            • Threshold from-0.010V to -0.050V,   ±5mV  accuracy• Flexible temperature protection threshold (Set up by external resistor)      • Charging over&under temperature protection      • Discharging over&under temperature protection• Cell balancing function• Open wire detection• Load detection• Ultra low power dissipation      • Normal working 20μA  (25°C)      • Sleep mode 5μA   (25°C)• Package type: SSOP24Application Field• Robotcleaner• Power tools• E-bike• Portable UPS• Other Lithium-ion or Lithium polymer battery packsApplication Field

CW1254 is 4~5 cells series protection IC which provides voltage, current, open wire, temperature protections and cell balancing.    Features    •Overcharge protection         • Threshold 3.650V, 3.850V,and 4.175V ~4.375V,   25mV steps,  ±25mV accuracy    •Over discharge protection         • Threshold from 2.300V to 2.800V,   100mV steps,   ±30mV accuracy    •Excess discharge current protection         • Excess discharge current 1：              • Threshold from 0.050V to 0.100V,   ±5mV  accuracy         • Excess discharge current 2：              • Threshold from 0.100V to 0.200V,    ±10mV  accuracy         • Short circuits protection              • Threshold from 0.200V to 0.500V,    ±20mV  accuracy         •Excess charge current protection              •Threshold from-0.010V to -0.050V,   ±5mV  accuracy    •Flexible temperature protection threshold (Set up by external resistor)         • Charging over&under temperature protection         • Discharging over&under temperature protection    •Cell balancing function    •Open wire detection    •Load detection    •Ultra low power dissipation         • Normal working 20μA  (25°C)         • Sleep mode 5μA   (25°C)    •Package type: SSOP16    Application Field    • Robotcleaner    • Power tools    • Portable UPS    • Other Lithium-ion or Lithium polymer battery packs    Application Circuits    .ueditorTableStyle {margin-bottom:10px;border-collapse:collapse;display:table;}.ueditorTableStyle table.noBorderTable td,.ueditorTableStyle table.noBorderTable th,.ueditorTableStyle table.noBorderTable caption{border:1px dashed #ddd !important}.ueditorTableStyle table.sortEnabled tr.firstRow th,.ueditorTableStyle table.sortEnabled tr.firstRow td{padding-right:20px; background-repeat: no-repeat;background-position: center right; background-image:url(undefinedthemes/default/images/sortable.png);}.ueditorTableStyle table.sortEnabled tr.firstRow th:hover,.ueditorTableStyle table.sortEnabled tr.firstRow td:hover{background-color: #EEE;}.ueditorTableStyle table{margin-bottom:10px;border-collapse:collapse;display:table;}.ueditorTableStyle td,.ueditorTableStyle th{ background:white; padding: 5px 10px;border: 1px solid #DDD;}.ueditorTableStyle caption{border:1px dashed #DDD;border-bottom:0;padding:3px;text-align:center;}.ueditorTableStyle th{border-top:1px solid #BBB;background:#F7F7F7;}.ueditorTableStyle table tr.firstRow th{border-top:2px solid #BBB;background:#F7F7F7;}.ueditorTableStyle tr.ue-table-interlace-color-single td{ background: #fcfcfc; }.ueditorTableStyle tr.ue-table-interlace-color-double td{ background: #f7faff; }.ueditorTableStyle td p{margin:0;padding:0;}

CW1251 is 3~5 cells 2nd protection IC which provides voltage protections.Description• 3~5 Cells Application• Overcharge Protection     • Threshold from 4.175V to 4.500V，25mV Steps, ±25mV Accuracy• Over discharge protection     • Threshold from 2.000V~3.000V, 100mV steps，±40mV accuracy• Low voltage battery detection     • Threshold option 0.2V, 0.5V, 1.0V, 1.5V, ±50mV accuracy• Open wire detection• Low power dissipation     • Normal operation 6μA (25°C)• Package Type: DFN10/MSOP10Applications• NoteBook• Tablet PC• E-Tools• Backup Power Supply• Other Lithium-ion or Lithium Polymer Battery PacksApplication Circuits

The CW6305B is a high accuracy linear charger IC with power path management for Wearables and IoT devices. It fulfills full charge phases, including pre-charge, fast charge constant current (CC), fast charge constant voltage (CV) and charging termination. The CW6305B integrates power path management (PPM) and supports full system reset and shipping mode.  It also provides system over current protection by limiting the current from the input to the system and that from the battery to the system. The CW6305 could monitor the battery pack temperature via the NTC pin (10K or 100K thermistor) and suspend the charging once the battery is in hot/cold condition. The device also integrates charge safety timer and pre-charge timer to off the charging when timer is expired. An I2C control interface allows the host to configure parameters to target values. I2C watchdog is available during charge and/or discharge.Features    • Linear Charger for Single Cell Li-ion/Li-Polymer Batteries        • +28V Maximum Voltage for the Input Source        • ±0.5% Charge Regulation Voltage Accuracy        • Up to 470mA Constant Current Charging        • Down to 1mA Termination Current        • Configurable 3.85V-4.6V Constant Voltage Charging in 12.5mV Steps        • Configurable 4.2V-4.95V VSYS Regulation Voltage in 50mV Steps    • Power Path Management        • System Reset and Shipping Mode Supported        • Instant On even When Battery is Exhausted    • Battery NTC Thermistor monitor     • Adjustable Thermal Regulation and Protection    • Over Current Protection in Discharge and Supplement Mode    • Charge Safety Timer and Pre-charge Timer    • I2C Interface and Watchdog during Charge and Discharge    • 1.58mm x 1.58mm CSP-9 Package    Application Field    • Smart Watches    • BT Headsets/TWS Earbuds    • Internet of Things Devices    Application Circuits     

CW6116 is a highly-integrated 3A switched-mode Li-Ion and Li-polymer battery charger with power path management. Its ultra-low impedance on power path helps improve charging efficiency, reduce charging time and extend battery life during discharge. The charging efficiency at 5V/2A is 92%. CW6116 supports USB-OTG with up to 1.5A supply current. Charging and system settings could be flexible configured via the I2C interface. Its compact QFN 4mmx4mm package, combing with using 1uH small profile inductor, makes it a good selection for fast charging application.Features    • Single Input Charger Support 3A Fast Charge        • 3.8V–13.5V Input Operating Voltage Range with +28V Absolute Input Voltage Rating        • ±0.5% Charge Voltage Accuracy and ±5% Charge Current Accuracy@1.5A        • Programmable Input Current Limit Supports USB 2.0/USB3.0 and Type-C        • Integrated Power MOSFETs        • Supports USB OTG with 1.5A Maximum Supply Current    • Power Path Management        • Enables System Instant-on with Deeply Discharged Battery        • Smart Power Allocation for System and Charging Current    • Programmable through I2C Interface    • Interrupt Signals for Abnormal Charging Status    • Integrated Thermal Regulation and Over Temperature Protection    • Support OVP and OCP    • Package QFN 4mmx4mm    Application Field   • Smart Phone    • Tablet    • Portable Device    Application Circuits