Linear Technology Corporation LTC 3110 2 A Bidirectional

Linear Technology Corporation LTC 3110: 2 A Bidirectional Buck-Boost DC/DC Regulator & Charger/Balancer Tony Armstrong Director of Product Marketing Power Products June, 2015 Linear Technology Confidential

2 LTC 3110 2 A Bidirectional Buck-Boost DC/DC Regulator & Charger/Balancer Super Capacitor Benefits: • High Peak power • 1000 times more Charge / Discharge cycles compared to batteries • Uncomplicated and fast charging possible • No damage from over discharge • High energy density compared to Electrolytic capacitors Super Capacitor Challenges: • Low voltage rating, typically 2. 5 V / cap • Charging requires accurate current limiting or large derating factors to avoid overloading the power source • Stacked capacitors must be continually balanced to prevent overvoltage • Wide discharge voltage range requires Step-Up/Step-Down conversion to maximize the usable stored energy • 10 X lower energy density compared to Lead-Acid Linear Technology Confidential April, 2013

3 LTC 3110: Why did we design this product? Industry’s first fully integrated power solution for supercapacitor-based Backup Power systems. The Bi-directional LTC 3110 Buck-Boost replaces two separate DC/DC converters (Backup Regulator + switching charger) and keeps the capacitors balanced. The supercap regulator is an Ultra-wide range Buck-Boost that operates as low as 100 m. V. Previous best was 1. 8 V. This ensures that all available energy from the Supercaps is usable for backup operation. 2 A capability in Backup mode is enough for smaller systems that just need to dump the RAM to Flash storage and smaller RF systems. Linear Technology Confidential April, 2013

4 LTC 3110 2 A Bidirectional Buck-Boost DC/DC Regulator and Charger/Balancer Common Supercapacitor applications: • Temporary power backup for data storage and remote communication systems • Peak load source for vehicle battery systems (caps supply the high peak currents, batteries supply the steady state) • Energy storage element for regenerative braking systems • Small power tools and flashlights Linear Technology Confidential April, 2013

5 LTC 3110 2 A Bidirectional Buck-Boost DC/DC Regulator and Charger/Balancer Linear Technology Confidential April, 2013

6 LTC 3110: What is Bidirectional? The DC current flow In one direction the LTC 3110 operates as buck-boost regulator taking current out from the super cap and is providing a regulated voltage to the load at VSYS. In the other direction the sign of the current flow reverses and an accurately limited current is flowing from the system rail back to charge the supercap. LTC 3110: What is Autonomous Back-Up and Recharge? • The LTC 3110 can be configured to always maintain a minimum system voltage level. If VSYS is dropping due to a power loss it can switch direction autonomously, delivering current from the supercap into VSYS stabilizing the system voltage. Linear Technology Confidential April, 2013

7 LTC 3110: 2 A, Bidirectional Buck-Boost DC/DC Regulator and Super. Cap Charger/Balancer FEATURES VCAP Operating Range: 0. 1 V to 5. 5 V VSYS Operating Range: 1. 71 V to 5. 25 V Automatic Switching from Charge to Back-Up Mode Programmable ± 2% Accurate Charge Input Current Limit – from 150 m. A to 2 A Automatic Backup Capacitor Balancing Fixed 1. 2 MHz Frequency Switching Burst Mode Operation: 40μA IQ Built-in Programmable Multipurpose Comparator with Open-Collector Outputs to Indicate Direction of Operation and End of Charge Low profile, thermally enhanced TSSOP-24 and 4 mm× 4 mm QFN-24 Packages APPLICATIONS Supercapacitor Back-Up Converter and Charger Battery Back-Up Converter and Charger Servers, RAID Systems RF Systems with Battery/Capacitor Back-Up Linear Technology Confidential April, 2013

8 LTC 3110: A look inside… Super Capacitor 1 or 2 Cells Active Voltage Balancer For Super Capacitor Internal Power FETs Bi-Directional Buck_boost Controller Internally Compensated End of Charging Supervisor PWM-Mode / Burst Mode Selector Linear Technology Confidential Accurate Charge Current Limit System Voltage Rail Fast Voltage Supervisor Selecting Back-Up-Mode Or Charge-Mode Accurate Threshold Additional General Purpose Comparator April, 2013

9 LTC 3110 TSSOP (FE) and QFN (UF) Packages Linear Technology Confidential April, 2013

10 LTC 3110 Demo Board • Contains Autonomous Back-Up System, including Supercap • Operation down to VCAP = 0. 1 V, after start up! Backside Active Area ~ 16 mm x 16 mm = 256 mm 2 Linear Technology Confidential April, 2013

11 LTC 3110 Demo Board - Backup Example (1 A) Back-Up Current VCAP VSYS 1 V / Div VMID 0 V Linear Technology Confidential Buck-Boost keeps the System Operational down to 700 m. V on Vcap! April, 2013

12 LTC’s Super. Cap Charger Family Product I-Charge VIN VOUT Comments LTC 3225 0. 15 A 2. 8 – 5. 5 V 4. 8/5. 3 V Charge Pump 2 SCAP LTC 3226 0. 33 A 2. 5 – 5. 5 V Charge Pump 2 SCAPs + Power. Path LTC 3625 1 A 2. 7 – 5. 5 V 4 – 5. 3 V 1, 2 Inductor Buck + Boost 2 SCAPs LTC 3110 2 A 0. 1 -5. 5 V 1. 8 – 5. 5 V Bi-Dir Buck-Boost 1 or 2 SCAPs LTC 3128 3 A 1. 7 – 5. 5 V 1. 8 – 5. 5 V Buck-Boost Charger for 1 or 2 SCAPs LTC 4425 3 A* 1. 7 – 5. 5 V 2. 7 – 5. 5 V Linear/Ideal Diode 2 SCAPs LTC 3355 1 A 3. 0 – 20 V 2. 7 – 5. 5 V System Buck + Boost Backup 1 SCA LTC 3350 10 A+ 4. 5 – 35 V 4. 0 – 35 V Bi-Dir Controller + Monitor 1 -4 SCAPs * limited by thermals Linear Technology Confidential April, 2013

13 LTC 3110 2 A Bidirectional Buck-Boost DC/DC Regulator and Charger/Balancer • Integrates all of the functionality required to exploit the benefits of super capacitors, charging, balancing and backup. High performance + simple design. • Input current limit with +/- 2% accuracy – Eliminates many external components, lowers Iq and can utilize full capability of Power source without exceeding safety limits. • Input Power sharing enables LTC 3110 and other DC/DC converters or loads to share the same power source with minimal derating/margin. • Active balancer synchronously shuttles charge between the capacitors, eliminating external ballast resistors and their power losses resulting in fewer recharge cycles and faster charging. • Will support lower power backup systems for SS Memory, RAID, Server, Remote communications Linear Technology Confidential April, 2013