DEMO MANUAL DC2151A LTC3331EUH Nanopower Buck-Boost DC/DC with Energy Harvesting Battery Charger Description Demonstration Circuit DC2151A is a nanopower buckboost DC/DC with energy harvesting battery charger featuring the LTC(R)3331. The LTC3331 integrates a high voltage energy harvesting power supply plus a DC/DC converter powered by a rechargeable cell battery to create a single output supply for alternative energy applications. The energy harvesting power supply, consisting of an integrated low-loss full-wave bridge with a high voltage buck converter, harvests energy from piezoelectric, solar or magnetic sources. The rechargeable cell input powers a buck-boost converter capable of operating down to 1.8V at its input. Either DC/DC converter can deliver energy to a single output. The buck operates when harvested energy is available, reducing the quiescent current drawn on the battery to essentially zero. The buck-boost takes over when harvested energy goes away. A 10mA shunt allows simple battery charging with harvest energy while a low battery disconnect function protects the battery from deep discharge. A supercapacitor balancer is also integrated, allowing for increased output storage. Voltage and current settings for input and output as well as the battery float voltage are programmable via pinstrapped logic inputs. The LTC3331EUH is available in a 5mm x 5mm 32-lead QFN surface mount package with exposed pad. L, L, LTC, LTM, LT, Burst Mode, OPTI-LOOP, Over-The-Top and PolyPhase are registered trademarks of Linear Technology Corporation. Adaptive Power, C-Load, DirectSense, Easy Drive, FilterCAD, Hot Swap, LinearView, Module, Micropower SwitcherCAD, Multimode Dimming, No Latency , No Latency Delta-Sigma, No RSENSE, Operational Filter, PanelProtect, PowerPath, PowerSOT, SmartStart, SoftSpan, Stage Shedding, SwitcherCAD, ThinSOT, UltraFast and VLDO are trademarks of Linear Technology Corporation. Other product names may be trademarks of the companies that manufacture the products. Board Photo 100 Buck Efficiency vs ILOAD 90 EFFICIENCY (%) 80 70 60 50 40 VOUT = 1.8V VOUT = 2.5V VOUT = 3.3V VOUT = 5V 30 20 10 0 Figure 1. DC2151A Demoboard VIN = 6V, L = 22H, DCR = 0.19 1 10 100 1m ILOAD (A) 10m Figure 2. Typical Efficiency of DC2151A 100m 3331 G34 dc2151af 1 DEMO MANUAL DC2151A Performance Summary Specifications are at TA = 25C SYMBOL PARAMETER CONDITIONS VIN Input Voltage Range VOUT 1.8V Output Voltage Range VOUT 2.5V Output Voltage Range VOUT 2.8V MIN MAX UNITS 3.0 to 18.0 V OUT0=0, OUT1=0, OUT2=0 1.728 to 1.872 V OUT0=1, OUT1=0, OUT2=0 2.425 to 2.575 V Output Voltage Range OUT0=0, OUT1=1, OUT2=0 2.716 to 2.884 V VOUT 3.0V Output Voltage Range OUT0=1, OUT1=0, OUT2=0 2.910 to 3.090 V VOUT 3.3V Output Voltage Range OUT0=0, OUT1=0, OUT2=1 3.200 to 3.400 V VOUT 3.6V Output Voltage Range OUT0=1, OUT1=0, OUT2=1 3.492 to 3.708 V VOUT 4.5V Output Voltage Range OUT0=0, OUT1=1, OUT2=1 4.365 to 4.635 V VOUT 5.0V Output Voltage Range OUT0=1, OUT1=1, OUT2=1 4.850 to 5.150 V VBAT 3.45V Float Voltage Range FLOAT1=0, FLOAT=0 3.381 to 3.519 V VBAT 4.00V Float Voltage Range FLOAT1=0, FLOAT=1 3.920 to 4.080 V VBAT 4.1V Float Voltage Range FLOAT1=1, FLOAT=0 4.018 to 4.182 V VBAT 4.2V Float Voltage Range FLOAT1=1, FLOAT=1 4.116 to 4.284 V Operating Principle Refer to the block diagram within the LTC3331 data sheet for its operating principle. a total drop of about 800mV at typical piezo-generated currents, but is capable of carrying up to 50mA. The LTC3331 combines a buck switching regulator and a buck-boost switching regulator to produce an energy harvesting solution with battery backup. The converters are controlled by a prioritizer that selects which converter to use based on the availability of a battery and/or harvestable energy. If harvested energy is available, the buck regulator is active and the buck-boost is off. With a battery charger and a supercapacitor balancer and an array of different configurations, the LTC3331 suits many applications. When the voltage on VIN rises above the UVLO rising threshold the buck converter is enabled and charge is transferred from the input capacitor to the output capacitor. When the input capacitor voltage is depleted below the UVLO falling threshold the buck converter is disabled. The synchronous buck converter is an ultralow quiescent current power supply tailored to energy harvesting applications. It is designed to interface directly to a piezoelectric or alternative A/C energy source, rectify and store the harvested energy on an external capacitor while maintaining a regulated output voltage. It can also bleed off any excess input power via an internal protective shunt regulator. An internal full-wave bridge rectifier, accessible via AC1 and AC2 inputs, rectifies AC sources such as those from a piezoelectric element. The rectified output is stored on a capacitor at the VIN pin and can be used as an energy reservoir for the buck converter. The bridge rectifier has 2 These thresholds can be set according to Table 4 of the data sheet which offers UVLO rising thresholds from 4V to 18V with large or small hysteresis windows. Two internal rails, CAP and VIN2, are generated from VIN and are used to drive the high side PMOS and low side NMOS of the buck converter, respectively. Additionally the VIN2 rail serves as logic high for output voltage select bits UV [3:0]. The VIN2 rail is regulated at 4.8V above GND while the CAP rail is regulated at 4.8V below VIN. These are not intended to be used as external rails. Bypass capacitors should be connected to the CAP and VIN2 pins to serve as energy reservoirs for driving the buck switches. When VIN is below 4.8V, VIN2 is equal to VIN and CAP is held at GND. VIN3 is an internal rail used by the buck and the buck-boost. When the LTC3331 runs the buck, VIN3 will be a Schottky diode drop below VIN2. When it runs as a buck-boost VIN3 is equal to BAT. dc2151af DEMO MANUAL DC2151A Operating Principle The buck regulator uses a hysteretic voltage algorithm to control the output through internal feedback from the VOUT sense pin. The buck converter charges an output capacitor through an inductor to a value slightly higher than the regulation point. It does this by ramping the inductor current up to 250mA through an internal PMOS switch and then ramping it down to 0mA through an internal NMOS switch. When the buck brings the output voltage into regulation, the converter enters a low quiescent current sleep state that monitors the output voltage with a sleep comparator. During this operating mode, load current is provided by the buck output capacitor. When the output voltage falls below the regulation point, the buck regulator wakes up and the cycle repeats. This hysteretic method of providing a regulated output reduces losses associated with FET switching and maintains an output at light loads. The buck delivers a minimum of 50mA average load current when it is switching. VOUT can be set from 1.8V to 5.0V via the output voltage select bits OUT [2:0] according to Table 1 of the data sheet. The buck-boost uses the same hysteretic algorithm as the buck to control the output, VOUT, with the same sleep comparator. The buck-boost has three modes of operation: buck, buck-boost and boost. An internal mode comparator determines the mode of operation based on BAT and VOUT. In each mode, the inductor current ramps up to IPEAK which is programmable via IPK [2:0]. See Table 3 of the data sheet. An integrated battery charger operating from the VIN2 rail charges the battery through the BB_IN pin. Connecting BB_IN to the BAT_OUT pin, an internal MOSFET Switch will then connect the battery charger to BAT_IN. The battery charger is a shunt regulator which can sink up to 10mA. The battery float voltage is programmable with two bits and a third bit is used to program the battery connect and disconnect voltage levels. This disconnect feature protects the battery from permanent damage by deep discharge. Disconnecting the battery from the BAT_OUT=BB_IN node prevents the load as well as the LTC3331 quiescent current from further discharging the battery. OUTPUT VOLTAGE 50mV/DIV AC-COUPLED EH_ON 4V/DIV 0V IBB_IN 200mA/DIV 0A 0A ICHARGE 1mA/DIV ACTIVE ENERGY HARVESTER ENABLES CHARGING OF THE BATTERY IN SLEEP BAT = 3.6V VOUT = 1.8V ILOAD = 50mA 100s/DIV 3331 TA01b Figure 3. Charging Battery with Harvested Energy A SHIP mode is provided which manually disconnects the battery. This may be helpful to prevent the battery from discharging when no harvestable energy is available for long periods of time, such as during shipping. Bring the SHIP pin high to engage the SHIP mode. To disengage the SHIP mode, bring the SHIP pin low. The BB_IN pin needs to be brought above the low battery connect (LBC) threshold to reconnect the battery. Power good comparator, PGVOUT, produces a logic high referenced to the highest of VIN2, BAT and VOUT less a Schottky diode drop. PGVOUT will transition high the first time the respective converter reaches the programmed SLEEP threshold, signaling that the output is in regulation. The pin will remain high until the voltage falls to 92% of the desired regulated voltage. An integrated supercapacitor balancer with 150nA of quiescent current is available to balance a stack of two supercapacitors. Typically the input, SCAP, will be tied to VOUT to allow for increased energy storage at VOUT with supercapacitors. The BAL pin is tied to the middle of the stack and can source or sink 10mA to regulate the BAL pin's voltage to half that of the SCAP voltage. To disable the balancer and its associated quiescent current, the SCAP and BAL pins can be tied to ground. dc2151af 3 DEMO MANUAL DC2151A Quick Start Procedure Using short twisted pair leads for any power connections, with all loads and power supplies off, refer to Figure 4 for the proper measurement and equipment setup. Follow the procedure below: 1. Before connecting PS1 to the DC2151A, PS1 must have its current limit set to 300mA and PS2 must have its current limit set to 100mA. For most power supplies with a current limit adjustment feature the procedure to set the current limit is as follows. Turn the voltage and current adjustment to minimum. Short the output terminals and turn the voltage adjustment to maximum. Adjust the current limit to 300mA for PS1 and 100mA for PS2. Turn the voltage adjustment to minimum and remove the short between the output terminals. The power supply is now current-limited to 300mA and 100mA respectively. 2. Initial Jumper, PS and LOAD settings: JP1 = 0 JP2 = 0 JP3 = 0 JP4 = 0 JP5 = 0 JP6 = 0 JP7 = 0 JP8 = 0 JP9 = 0 JP10 = 0 JP11 = RUN JP12 = OFF PS1 = OFF PS2 = OFF LOAD1 = OFF Remove battery from battery holder 6. Decrease PS1 to 0V and disconnect PS1 from VIN. Set the current limit of PS1 to 25mA as described above. 7. Move the connection for PS1 from VIN to AC1. Slowly increase PS1 voltage to 2.0V while monitoring the input current. If the current remains less than 5mA, increase PS1 to 19V. Verify voltage on VOUT is within the VOUT 1.8V range listed in the Performance Summary. Decrease PS1 to 0V, swap the AC1 connection to AC2 and repeat the test. Decrease PS1 to 0V and move the connection for PS1 from AC2 to VIN. 8. Set JP5 to 1, JP6 to 1, and JP7 to 1. Increase PS1 to 19V and set LOAD1 to 50mA. Verify voltage on VOUT is within the VOUT 5.0V range listed in the Performance Summary. Verify that the output ripple voltage is between 40mV and 90mV. Set PS1 to 0V. 9. Set the current limit of PS2 to 60mA as described above. Set JP1 to 0, JP2, JP3 and JP4 to 1, JP5-JP7 to 1 and JP8-JP10 to 0. Set JP12 to CHARGE. Increase PS1 to 12V and set LOAD1 to 0mA. Connect PS2 to the BAT_IN Terminals, then turn on PS2 and slowly increase voltage to 1.0V while monitoring the input current. If the current remains less than 15mA, increase PS2 until VM4 reads 2.7V. Verify that the current in AM2 is approximately 660A. Increase PS2 to 3.5V and verify that VM4 is approximately 3.45V. 3. Connect PS1 to the VIN Terminals, then turn on PS1 and slowly increase voltage to 2.0V while monitoring the input current. If the current remains less than 5mA, increase PS1 to 5.0V. 10. Set JP8-JP10 to 1. Increase PS1 to 12V and set LOAD1 to 0mA. Set PS2 to 3.7V. Verify that the current in AM2 is approximately 330A. Increase PS2 to 4.3V and verify that VM4 is approximately 4.2V. 4. Set LOAD1 to 50mA. Verify voltage on VOUT is within the VOUT 1.8V range listed in the Performance Summary. Verify that the output ripple voltage is between 10mV and 50mV. Verify that PGVOUT is high. Decrease LOAD1 to 5mA. Verify that PGVOUT and EH_ON are high. Decrease PS1 to 2.0V. Verify that VOUT is 0V. 11. Set JP12 to FAST_CHRG. Set PS2 to 3.7V. Verify that the current in AM2 is approximately 10mA. Set JP12 to CHARGE 5. Set JP1, JP2, JP3, JP4 to 1. Slowly increase PS1 to 16V and verify that VOUT is off. Increase PS1 to 19V and verify that VOUT is within the VOUT 1.8V range listed in the Performance Summary. Decrease PS1 to 4.0V. Verify that VOUT is 0V. 4 12. Set the current limit of PS2 to 100mA as described above. Set PS1 to 14V. Set JP1 to 1, JP2, JP3 and JP4 to 0, JP5 to 0, JP6 and JP7 to 1. Set JP8 to 0. Set PS2 to 3.2V. Set LOAD1 to 5mA. Remove PS1 lead from the VIN turret. Verify voltage on VOUT is within the VOUT 3.0V range listed in Performance Summary. Verify that PGVOUT is high and EH_ON is low. Decrease PS2 to 2.6V and verify that VOUT is 0V. Increase PS2 to 3.8V. Press and release PB1. Verify the VOUT is 3.0V. dc2151af DEMO MANUAL DC2151A Quick Start Procedure 13. Reconnect PS1 to VIN turret. Set PS1 to 14V. Set JP8 to 1. Set PS2 to 3.8V. Set LOAD1 to 5mA. Remove PS1 lead from the VIN turret. Verify voltage on VOUT is within the VOUT 3.0V range listed in Performance Summary. Verify that PGVOUT is high and EH_ON is low. Decrease PS2 to 3.1V and verify that VOUT is 0V. Increase PS2 to 4.3V. Press and release PB1. Verify the VOUT is 3.0V. 14. Set JP11 to SHIP and verify that VOUT is approximately 0V. 15. Decrease PS2 to 0V and disconnect PS2. 16. Set the current limit of PS1 to 300mA as described above. Connect PS1 to the VIN Terminals. Set JP5 to 1, JP6 to 1 and JP7 to 1. Set PS1 to 14V. Set LOAD1 to 50mA. Add a jumper lead from VOUT to SCAP. Verify that BAL is approximately half of VOUT. 17. Quickly remove PS1+ lead from VIN and verify that VOUT remains above 1.2V for approximately 5 seconds. 18. Turn off PS1, PS2 and LOAD1. Reinstall battery in battery holder. Figure 4. Proper Measurement Equipment Setup dc2151af 5 DEMO MANUAL DC2151A Connection to a Dust Mote (DC9003A-B) Attach a Dust(R) Mote to J1 of the DC2151A, refer to Figure 5 for the proper setup. J1 is a keyed connector and is connected to the left side of the P1 connector on the DUST Mote. Figure 13 is a schematic of the Dust Mote and the DC2151A interconnections plus three extra connections which 1) connect the SCAP to VOUT, 2) connect BAL to the middle of the supercapacitors and 3) connect EH_ON to OUT2. The DC2151A contains NC7SZ58P6X Universal Configurable 2-Input logic gates that are input voltage tolerant and allow level shifting between the LTC3331 and the Dust Mote. Remove the battery from the BH1 holder on the bottom side of the DC2151A. On the DC2151A, set JP1 to 1, JP2 to 0, JP3 to 1, JP4 to 0, JP5 to1, JP6 to 0, JP7 to 0, JP8, JP9 and JP10 to 0, JP11 to RUN. Piezoelectric Transducer Evaluation Mount a series connected MIDE V25W to a vibration source and connect the electrical connections to the AC1 and AC2 turrets. Activate the vibration source to an acceleration of 1g and a frequency of 60Hz. Figure 6 shows an open-circuit voltage of 10.6V for the MIDE V25W piezoelectric device that was tuned to 60Hz. In order to set the VIN_UVLO_RISING and VIN_UVLO_FALLING thresholds, the open-circuit voltage of the piezoelectric device must be measured. The internal bridge network of the LTC3331 will have approximately 800mV drop at an input current of 300A. Figure 5. DC2151A with Dust Mote 6 dc2151af DEMO MANUAL DC2151A Connection to a Dust Mote (DC9003A-B) compares well with the input power that is charging CIN during the sleep cycle between VIN_UVLO_FALLING and VIN_UVLO_RISING thresholds at an acceleration force of 1grms, shown in Figure 8 below. VAC_OC 1G 5.00V/DIV EH_ON 5.00V/DIV 5ms/DIV DC2051A FIG06 Figure 6. MIDE V25W Open-Circuit AC Voltage with 1grms, 60Hz Acceleration Applied The peak-power-load voltage of a purely resistive source is at one-half of the rectified no-load voltage. In this case, the optimal average input-voltage regulation level would be 4.9V. Using a VIN_UVLO_RISING threshold of 6V and a VIN_UVLO_FALLING threshold of 5V (UV3 = 0, UV2 = 0, UV1 = 1, UV0 = 0) yields an average input voltage close to the theoretical optimal voltage. Figure 7 is a plot of the output power and load voltage of the V25W piezoelectric transducer into a 42.2k load for various rms acceleration levels. The output power 700 6.000 600 5.000 POWER (W) 400 4.000 LOAD VOLTAGE (VRMS) 3.000 300 200 POWER (W) 2.000 1.000 100 0 0.250 0.375 VIN 2.00V/DIV 50.0ms/DIV DC2051A F08 Figure 8. MIDE V25W Charging the 18F input capacitance from 4.48V to 5.92V in 208ms In Figure 8, the input capacitor is being recharged from the V25W piezoelectric transducer. The input capacitor is charging from 4.48V to 5.92V in 208 milliseconds. The power delivered from the V25W is 648W. CIN * (VIN12 - VIN22 ) PCIN = 2 * t LOAD VOLTAGE (VRMS) 500 VOUT 1.00V/DIV 0.000 0.500 0.625 0.750 0.875 1.000 FORCE (g) DC2051A G01 Figure 7. MIDE V25W Output Power into a 42.2k Load with 1grms, 60Hz Acceleration Applied the MIDE V25W Piezoelectric Transducer, [2 * sin(2 * 60Hz * t)] 18F * (5.922 - 4.482 ) PCIN = 2 * 208ms PCIN = 648W Assuming that the circuit is configured as shown in Figure 9, it will take a significant amount of time for the piezo transducer to charge the 0.09F supercapacitor on the output of the LTC3331. As used above, the 22F input capacitor is only 18F at an applied voltage of 5V, so every VIN_UVLO_RISING and FALLING event produces 26 micro-coulombs [(5.92V - 4.48V) * 18F)] that may be transferred from the input capacitor to the output capacitor, dc2151af 7 DEMO MANUAL DC2151A Connection to a Dust Mote (DC9003A-B) PIEZO MIDE V25W 1F 6.3V 22F 25V VIN AC2 CAP VIN2 4.7F 6.3V AC1 SWB LTC3331 SW 22H 2.5V VOUT UV3 180mF 2.7V SCAP UV2 100F 6.3V BAL UV1 UV0 2F 6.3V 100H SWA PGVOUT EH_ON VIN3 BAT_IN 180mF 2.7V HZ202F IPK2 IPK1 CHARGE IPK0 OUT2 22F 6.3V BAT_OUT BB_IN FLOAT1 FLOAT0 OUT1 OUT0 LBSEL SHIP GND 0.1F 6.3V DC2051A F09 Figure 9. LTC3331 Circuit Charging Supercapacitor at No Load without a battery (Vout=3.6V) minus the losses of the buck regulator in the LTC3331. The buck regulator efficiency is approximately 90% at VIN equal to 5V and VOUT between 2.5V and 3.6V. Thus, for every UVLO event, 23.3 micro-coulombs are added to the output supercapacitor. Given a 0.09F output supercapacitor charging to 3.6V, 324 milli-coulombs are required to fully charge the supercapacitor. Assuming no additional load on the output, it takes 13,906 (.324/23.3e-6) UVLO events to charge the output supercapacitor to 3.6V. From Figure 8, it can be observed that each VIN_UVLO event takes 208ms, so the total time to charge the output capacitor from 0V to 3.6V will be greater than 2900 seconds. Figure 10 shows the no-load charging of the output supercapacitor, which takes approximately 3300 seconds. The above calculation neglects the lower efficiency at low output voltages and the time it takes to transfer the energy from the input capacitor to the output supercapacitor, so predicting the actual value within -12% is to be expected. EH_ON 5.00V/DIV VOUT 2.00V/DIV VIN 2.00V/DIV 500s/DIV DC2051A F10 Figure 10. Scope Shots of LTC3331 Charging Supercapacitor at No Load without a Battery (Vout = 3.6V) 8 dc2151af DEMO MANUAL DC2151A Connection to a Dust Mote (DC9003A-B) PIEZO MIDE V25W 22F 25V 1F 6.3V VIN AC2 CAP VIN2 4.7F 6.3V AC1 SWB LTC3331 SW UV1 UV0 2F 6.3V BAT_IN 22H 2.5V VOUT UV3 180mF 2.7V SCAP UV2 Li-ION BATTERY 100H SWA 100F 6.3V PULSE 15mA 10ms BAL PGVOUT EH_ON VIN3 180mF 2.7V HZ202F IPK2 IPK1 CHARGE IPK0 OUT2 22F 6.3V BAT_OUT BB_IN FLOAT1 FLOAT0 OUT1 OUT0 LBSEL SHIP GND 0.1F 6.3V DC2051A F Figure 11. LTC3331 Circuit with a Supercapacitor, a Battery installed and a pulsed load applied (Vout=3.6V) Figure 11 shows the LTC3331 with a supercapacitor on the output, a battery installed and the output voltage set to 3.6V. The scope shots in Figure 12 were taken after applying a pulsed load of 15mA for 10ms. With the battery attached and a pulsed load applied, the EH_ON signal will switch back and forth from high to low every time the VIN voltage transitions from the VIN_UVLO_RISING to the VIN_UVLO_FALLING threshold. When the pulsed load is applied, the output capacitor is depleted slightly and the input capacitor must recharge the output cap. Because the input capacitance is much less then the output capacitance, the input capacitor will go through many UVLO transitions to charge the output capacitor back up to the sleep threshold. Once the output is charged to the output sleep threshold, the EH_ON signal will again be consistently high indicating that the energy harvesting source is powering the output. EH_ON 5.00V/DIV VIN 2.00V/DIV VOUT 50.0mV/DIV LOAD CURRENT 20.0mA/DIV 1.00s/DIV DC2051A F12 Figure 12. Charging a Supercapacitor with a battery installed and a pulsed load (Vout=3.6V) dc2151af 9 DEMO MANUAL DC2151A Connection to a Dust Mote (DC9003A-B) Figure 13 shows the LTC3331 with an output supercapacitor, a Dust Mote attached, a battery installed and EH_ON connected to OUT2. In this configuration, when EH_ON is low, VOUT will be set to 2.5V and when EH_ON is high, VOUT will be set to 3.6V. The first marker in Figure 14 is where the vibration source was activated; VIN then rises above the VIN_UVLO_RISING threshold. EH_ON will then go high causing VOUT to rise towards 3.6V (VOUT started at 2.5V because the battery had charged it up initially). At the same time EH_ON goes high, PGVOUT will go low, since the new VOUT level of 3.6V has not been reached. As the charge on VIN is being transferred to VOUT, VIN is discharging and when VIN reaches its UVLO_FALLING threshold, EH_ON will go PGVOUT 5.00V/DIV EH_ON 5.00V/DIV VOUT 1.00V/DIV VIN 2.00V/DIV 200s/DIV DC2051A F14 Figure 14. MIDE 25W Charging Output Supercapacitor from 2.5V to 3.6 V with DUST Mote Attached MIDE V25W AC2 1F 6.3V 22F 25V VIN2 UVLO RISING = 12V* UVLO FALLING = 11V IPEAK_BB = 100mA 3.45V + LiFePO4 1F 6.3V SWA SWB CAP 4.7F 6.3V AC1 VIN LTC3331 22H VOUT = 3.6V FOR EH_ON = 1 VOUT = 2.5V FOR EH_ON = 0 22H SW VOUT UV3 SCAP UV2 BAL UV1 PGVOUT UV0 EH_ON 1F 2.7V 1F 2.7V VIN3 BAT_IN IPK2 PGOOD IPK1 EHORBAT OUT2 130k NC7SZ58P6 x2 OUT1 BAT_OUT OUT0 BB_IN FLOAT1 FLOAT0 VSUPPLY TX IPK0 CHARGE 22F 6.3V 22F 6.3V LBSEL 0.1F 6.3V SHIP GND DC2051A F13 GND LINEAR TECHNOLOGY DC9003A-AB DUST MOTE FOR WIRELESS MESH NETWORKS *FOR PEAK POWER TRANSFER, CENTER THE UVLO WINDOW AT HALF THE RECTIFIED OPEN CIRCUIT VOLTAGE OF THE PIEZO Figure 13. Dust Mote Setup with a Supercapacitor, a battery and EH_ON connected to OUT2 10 dc2151af DEMO MANUAL DC2151A Connection to a Dust Mote (DC9003A-B) low, causing the targeted VOUT to again be 2.5V. Given that the output capacitor is very large and the average load is less than the input power supplied by the MIDE piezoelectric transducer, the output voltage will increase to the higher setpoint of 3.6V over many cycles. During the transition from the BAT setpoint of 2.5V to the energy harvester setpoint of 3.6V, VOUT is above the 2.5V PGVOUT threshold, hence, PGVOUT will go high every time EH_ON goes low. This cycle will be repeated until VOUT reaches the PGVOUT threshold for the VOUT setting of 3.6V. When a pulse load is applied that is greater than the energy supplied by the input capacitor, VIN will drop below the VIN_UVLO_FALLING threshold, EH_ON will go low and the buck-boost regulator will be ready to support the load requirement from the battery, but will not start to switch until the supercapacitor is discharged to 2.5V. In this way, the circuit can store a lot of harvested energy and use it for an extended period of time before switching over to the battery energy. The supercapacitor could be sized to accommodate known repeated periods of time that the energy harvester source will not be available, such as overnight when a vibrating machine is turned off or, in the case of a solar application, when the lights are turned off or the sun goes down. While the EH_ON signal is low, the buck-boost circuit will consume 750nA from the battery in the sleeping state. The effects of a pulsed load are shown in Figure 14 at approximately 1850 seconds, where VIN is discharged and the EH_ON signal pulses low to high for a brief period of time, which occurred as a result of the Dust Mote radio making a data transmission. PGVOUT 5.00V/DIV EH_ON 5.00V/DIV VOUT 1.00V/DIV VIN 2.00V/DIV 200s/DIV DC2051A F15 Figure 15. Output Supercapacitor Discharging when the vibration source is switched off Figure 15 shows the discharging of VOUT when the vibration source is removed and VIN drops below the UVLO_FALLING threshold, causing EH_ON to go low. The supercapacitor on VOUT will discharge down to the new target voltage of 2.5V, at which point the buck-boost regulator will turn on, supplying power to the Dust Mote. The discharging of the supercapacitor on VOUT provides an energy source for short term loss of the vibration source and extends the life of the battery. Figure 16 is the same Dust mote configuration as Figure 13 but without the output supercapacitor. Figure 17 shows the charging of the output without the supercapacitor attached. dc2151af 11 DEMO MANUAL DC2151A Connection to a Dust Mote (DC9003A-B) MIDE V25W AC2 22F 25V 1F 6.3V AC1 VIN SWA SWB CAP LTC3331 VIN2 4.7F 6.3V UVLO RISING = 12V* UVLO FALLING = 11V IPEAK_BB = 100mA 3.45V + LiFePO4 1F 6.3V 22H VOUT = 3.6V FOR EH_ON = 1 VOUT = 2.5V FOR EH_ON = 0 22H SW VOUT UV3 SCAP UV2 BAL UV1 PGVOUT UV0 EH_ON 100F 6.3V VIN3 BAT_IN IPK2 PGOOD IPK1 TX IPK0 CHARGE EHORBAT OUT2 130k 22F 6.3V VSUPPLY BAT_OUT OUT1 BB_IN OUT0 FLOAT1 FLOAT0 LBSEL NC7SZ58P6 x2 0.1F 6.3V SHIP GND DC2051A F16 GND LINEAR TECHNOLOGY DC9003A-AB DUST MOTE FOR WIRELESS MESH NETWORKS *FOR PEAK POWER TRANSFER, CENTER THE UVLO WINDOW AT HALF THE RECTIFIED OPEN CIRCUIT VOLTAGE OF THE PIEZO Figure 16. Dust Mote Setup without a Supercapacitor and with EH_ON Connected to OUT2 PGVOUT 5.00V/DIV EH_ON 5.00V/DIV VOUT 1.00V/DIV VIN 2.00V/DIV 100ms/DIV DC2051A F17 Figure 17. Output Voltage Charging with Dust Mote Attached without Supercapacitor 12 dc2151af DEMO MANUAL DC2151A Parts List ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER Required Circuit Components 1 1 BAT1 CR2032 COIN LI-ION BATTERY POWERSTREAM, Lir2032 2 1 BTH1 BATTERY HOLDER COIN CELL 2032 SMD MPD INC, BU2032SM-HD-G 3 1 C1 SUPERCAP, 90mF, 5.5V, 20mm x 15mm CAP-XX, HZ202F-1 4 1 C2 CAP, CHIP, X5R, 150F, 20%, 6.3V, 1210 SAMSUNG, CL32A157MQVNNNE 5 1 C3 CAP, CHIP, X5R, 1F, 10%, 6.3V, 0402 SAMSUNG, CL05A105KQ5NNNC 6 1 C4 CAP, CHIP, X5R, 22F, 10%, 25V, 1210 SAMSUNG, CL32A226KAJNNNE 7 1 C5 CAP, CHIP, X5R, 4.7F, 10%, 6.3V, 0603 SAMSUNG, CL10A475KQ8NNNC 8 1 C6 CAP, CHIP, X5R, 0.1F, 10%, 10V, 0402 TDK, C1005X5R1A104K 9 1 C7 CAP, CHIP, X5R, 22F, 20%, 6.3V, 1206 SAMSUNG, CL31A226MQHNNNE 10 1 L1 INDUCTOR, 22H, 0.800A, 0.36, 3.9mm x 3.9mm COILCRAFT, LPS4018-223MLB 11 1 L2 INDUCTOR, 22H, 0.75A, 0.19, 4.8mm x 4.8mm COILCRAFT, LPS5030-223MLB 12 3 R2, R4, R6 RES, CHIP, 0, 0603 VISHAY, CRCW06030000Z0EA 13 1 R10 RES, CHIP, 3.01K, 1/16W, 1%, 0402 VISHAY, CRCW04023K01FKED 14 1 U1 NANOPOWER BUCK-BOOST DC/DC WITH EH BATTERY CHARGER LINEAR TECHNOLOGY, LTC3331EUH#TRPBF Additional Demo Board Circuit Components 1 0 C8, C9 CAP, CHIP, X5R, 0.1F, 10%, 10V, 0402 (OPT) TDK, C1005X5R1A104K 2 0 C10 SUPERCAP/ULTRACAPACITOR, 330mF, 5.5V, 60m DOUBLE CELL MURATA, DMF3R5R5L334M3DTA0 3 1 D1 DIODE, SCHOTTKY, 30V, 0.1A, SOD-523 CENTRAL, CMOSH-3 4 0 BTH2 SMT, CR2477 BATTERY HOLDER RENATA, SMTU2477-1 5 1 R1 RES, CHIP, 100, 1/16W, 1%, 0402 VISHAY, CRCW0402100RFKED 6 0 R3, R5, R7 RES, CHIP, 0, 0603 (DNP) VISHAY, CRCW06030000Z0EA 7 0 R8, R9 RES, CHIP, 7.5K, 1/16W, 1%, 0402 VISHAY, CRCW04027K50FKED 8 1 R11 RES, CHIP, 56.2, 1/16W, 1%, 0402 VISHAY, CRCW040256R2FKED 9 2 R12, R14 RES, CHIP, 1.00M, 1/16W, 1%, 0402 VISHAY, CRCW04021M00FKED 10 1 R13 RES, CHIP, 100K, 1/16W, 1%, 0402 VISHAY, CRCW0402100KFKED 11 1 Q1 SMT, DUAL MOSFET, NCHANNET/PCHANNET, 60V, SuperSOT-6 FAIRCHILD, NDC7001C 12 1 Q2 SMT, BIPOLAR, PNP, 60V, SOT-23 CENTRAL, CMPT3906E 13 2 U2, U3 IC, UHS UNIV. CONFIG. TWO-INPUT GATES, SC70-6 FAIRCHILD, NC7SZ58P6X 1 13 E1-E6, E10-E17 TURRET, 0.09 DIA MILL-MAX, 2501-2-00-80-00-00-07-0 2 3 E7-E9 TURRET, 0.061 DIA MILL MAX, 2308-2-00-80-00-00-07-0 3 1 J1 HEADER, 12 PIN, DUST HEADER 2X6 SAMTEC, SMH-106-02-L-D-05 4 10 JP1-JP10 HEADER, 3 PIN 0.079 SINGLE ROW WURTH, 62000311121 5 2 JP11, JP12 HEADER, 4 PIN 0.079 SINGLE ROW WURTH, 62000411121 6 12 JP1-JP12 SHUNT, 2mm WURTH, 60800213421 dc2151af 13 A B C D JP5 GND 0 E5 E4 E3 E2 E1 22uF 1210 25V C4 GND E6 + BTH1 5 CHARGE PB1 JP8 VIN3 VIN2 CAP VIN AC2 AC1 CHARGE 0 START OPT BTH2 SMTU2477N-LF 4 0 JP9 FLOAT1 1 0 JP10 FLOAT0 1 * 7 6 5 4 17 PGVOUT SHIP EXT RUN JP11 SHIP EH_ON OPT R8 7.5k OPT R9 7.5k 4 VOUT 2 - BAL + SCAP E11 E12 E7 E9 E13 GND GND 3 THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 SCALE = NONE 2 PRODUCTION FAB 2 - 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 UV0 DATE: N/A SIZE JD APPROVED DATE 2 - 21 - 14 IPK1 IPK0 ILIM R5 R7 5mA R5 R6 10mA R4 R7 15mA R4 R6 25mA R5 R7 50mA R5 R6 100mA R4 R7 150mA R4 R6 250mA 2 - 21 - 14 IC NO. 1 LTC3331EUH DEMO CIRCUIT 2151A SHEET 1 OF 2 2 REV. 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 www.linear.com Fax: (408)434-0507 LTC Confidential-For Customer Use Only IPK2 R3 R3 R3 R3 R2 R2 R2 R2 ILM SELECTION INSTALL OUT2 OUT1 OUT0 VOUT 1.8V 0 0 0 0 2.5V 0 1 0 2.8V 1 0 3.0V 0 1 1 3.3V 1 0 0 3.6V 1 0 1 4.5V 1 1 0 5.0V 1 1 1 OUTPUT VOLTAGE SELECTION NANOPOWER BUCK - BOOST DC / DC WITH ENERGY HARVESTING BATTERY CHARGER TECHNOLOGY UVLO UVLO RISING FALLING 3V 4V 4V 5V 5V 6V 6V 7V 7V 8V 5V 8V 9V 10V 5V 10V 12V 11V 5V 12V 14V 13V 5V 14V 16V 15V 5V 16V 18V 17V 18V 5V TITLE: SCHEMATIC 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 UV1 UVLO SELECTION 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 JD 1 LBSEL FLOAT1 FLOAT0 FLOAT CONNECT DISCONNECT 3.45V 2.04V 0 0 0 2.37V 4.0V 2.70V 0 0 1 3.05V 4.1V 0 2.70V 1 0 3.05V 0 2.70V 4.2V 1 1 3.05V 1 2.51V 3.45V 0 0 2.86V 4.0V 3.20V 1 0 1 3.55V 4.1V 0 3.20V 1 1 3.55V 3.20V 4.2V 3.55V 1 1 1 UV2 NC DESCRIPTION REVISION HISTORY REV ECO FLOAT SELECTION AND BATTERY DISCONNECT THRESHOLDS UV3 2 APPROVALS EH_ON PGVOUT BAL DMF3R5R5L334M3DTA0 OPT C10 330mF 5.5V 21mm x 14mm E14 VIN2 VOUT 1.8V - 5.0V 50mA GND E17 JP4 UV0 E16 0 1 CUSTOMER NOTICE HZ202F C1 90mF 5.5V 20mm x 15mm JP3 C2 150uF 1210 6.3V 20% 0 0 JP2 1 1 UV1 Figure 18. DC2151A Demo Circuit Schematic, Page 1 3. INSTALL SHUNTS ON JUMPERS AS SHOWN. 2. ALL CAPACITORS ARE IN MICROFARADS, 0402, 10%, 10V. 1. ALL RESISTORS ARE IN OHMS, 0402, 1%, 1/16W. NOTES: UNLESS OTHERWISE SPECIFIED BAL + R7 DNP UV2 R6 VIN3 0 3 LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS; HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO PCB DES. VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL APP ENG. APPLICATION. COMPONENT SUBSTITUTION AND PRINTED CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT PERFORMANCE OR RELIABILITY. CONTACT LINEAR TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE. 0.1uF 10V C8 3 OPT OPT 0.1uF 10V C9 JP1 22uH L2 R5 R4 UV3 22uH L1 0 1 DNP R3 DNP 15 SWA 14 SWB 12 SW 13 VOUT 2 SCAP UV0 UV1 UV2 UV3 IPK0 0 R2 0 BB_IN * PLACE JP11 IN SHIP POSITION WHEN BOARD IS NOT IN USE. 100 R1 U1 LTC3331EUH 27 16 BB_IN 20 BAT_OUT 26 3 11 10 9 8 0 LBSEL 1 VIN3 WURTH- 434 111 025 826 BB_IN C7 22uF 1206 6.3V 20% BB_IN 10V VIN3 6.3V C6 0.1uF VIN2 0603 FAST_CHRG SMTU2032-LF 2.0V - 4.2V BAT_IN E15 FAST CHARGE E8 JP12 CHARGE CHARGE OFF CHARGE JP7 C3 1uF 6.3V 0 4.7uF VIN JP6 1 OUT0 C5 0 1 OUT1 BB_IN 2.0V - 4.2V 125mA R10 * 10mA, 3.01k (IF VBB_IN > VFLOAT) BB_IN GND 3V - 19V VIN AC2 AC1 CAUTION: 50mA MAX E10 5 21 22 1 1 I 2 1 I 2 32 OUT2 31 OUT1 30 OUT0 BAT_IN LBSEL 23 FLOAT1 24 FLOAT0 33 GND 25 SHIP 29 EH_ON 28 PGVOUT 18 IPK1 19 IPK2 BAL 1 2 1 1 3 14 + OUT2 A B C D DEMO MANUAL DC2151A Schematic Diagram dc2151af Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights. A B C EH_ON PGVOUT VOUT 5 3 I0 1 I1 6 I2 3 I0 1 I1 6 I2 4 Y 4 NC7SZ58P6X U3 Y NC7SZ58P6X U2 4 L L L L H L I0 H L Y Y= ( I 0 ) . ( I2 ) + ( I 1 ) . ( I2 ) I1 I2 U2, U3, U4 FUNCTION TABLE 4 OVERVOLTAGE TOLERANT BUFFERS TRANSLATE THE HIGH PULL-UP VOLTAGES FROM THE LTC3330 TO THE VOUT VOLTAGE DRIVING THE PROCESSOR I/O BUS, WHICH IS VOUT. EH_ON PGVOUT VOUT 5 VCC GND 2 VOUT 5 VCC GND 2 +5V I/O 2 RSVD SMH-106-02-L-D-05 DUST HEADER 2X6 V+ I/O 1 KEY GND VSUPPLY EHORBAT VBAT PGOOD NC J1 D1 CMOSH-3 BB_IN CUSTOMER NOTICE VOUT 3 THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. 3 2 NDC7001C 2 SCALE = NONE JD NC 6 5 DATE: N/A SIZE 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 www.linear.com Fax: (408)434-0507 LTC Confidential-For Customer Use Only 1 LTC3331EUH DEMO CIRCUIT 2151A SHEET 2 OF 2 2 REV. NANOPOWER BUCK - BOOST DC / DC WITH ENERGY HARVESTING BATTERY CHARGER 2 - 21 - 14 IC NO. 1 FAST_CHRG 1.00Meg R14 TECHNOLOGY 100k R13 1 CMPT3906E Q2 TITLE: SCHEMATIC R11 I_CHRG 113 5mA 75.0 7.5mA 56.2 10mA APPROVALS 1 Q1A R12 1.00Meg BATTERY CHARGE CURRENT * 4 2 * R11 56.2 LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS; HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO PCB DES. VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL APP ENG. APPLICATION. COMPONENT SUBSTITUTION AND PRINTED CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT PERFORMANCE OR RELIABILITY. CONTACT LINEAR TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE. 11 9 7 5 3 1 Q1B NDC7001C VIN Figure 19. DC2151A Demo Circuit Schematic, Page 2 12 10 8 6 4 2 3 2 1 2 3 D 5 A B C D DEMO MANUAL DC2151A Schematic Diagram dc2151af 15 DEMO MANUAL DC2151A DEMONSTRATION BOARD IMPORTANT NOTICE Linear Technology Corporation (LTC) provides the enclosed product(s) under the following AS IS conditions: This demonstration board (DEMO BOARD) kit being sold or provided by Linear Technology is intended for use for ENGINEERING DEVELOPMENT OR EVALUATION PURPOSES ONLY and is not provided by LTC for commercial use. As such, the DEMO BOARD herein may not be complete in terms of required design-, marketing-, and/or manufacturing-related protective considerations, including but not limited to product safety measures typically found in finished commercial goods. As a prototype, this product does not fall within the scope of the European Union directive on electromagnetic compatibility and therefore may or may not meet the technical requirements of the directive, or other regulations. If this evaluation kit does not meet the specifications recited in the DEMO BOARD manual the kit may be returned within 30 days from the date of delivery for a full refund. THE FOREGOING WARRANTY IS THE EXCLUSIVE WARRANTY MADE BY THE SELLER TO BUYER AND IS IN LIEU OF ALL OTHER WARRANTIES, EXPRESSED, IMPLIED, OR STATUTORY, INCLUDING ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE. EXCEPT TO THE EXTENT OF THIS INDEMNITY, NEITHER PARTY SHALL BE LIABLE TO THE OTHER FOR ANY INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES. The user assumes all responsibility and liability for proper and safe handling of the goods. Further, the user releases LTC from all claims arising from the handling or use of the goods. Due to the open construction of the product, it is the user's responsibility to take any and all appropriate precautions with regard to electrostatic discharge. Also be aware that the products herein may not be regulatory compliant or agency certified (FCC, UL, CE, etc.). No License is granted under any patent right or other intellectual property whatsoever. LTC assumes no liability for applications assistance, customer product design, software performance, or infringement of patents or any other intellectual property rights of any kind. LTC currently services a variety of customers for products around the world, and therefore this transaction is not exclusive. Please read the DEMO BOARD manual prior to handling the product. Persons handling this product must have electronics training and observe good laboratory practice standards. Common sense is encouraged. This notice contains important safety information about temperatures and voltages. For further safety concerns, please contact a LTC application engineer. Mailing Address: Linear Technology 1630 McCarthy Blvd. Milpitas, CA 95035 Copyright (c) 2004, Linear Technology Corporation 16 Linear Technology Corporation dc2151af LT 0614 * PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 FAX: (408) 434-0507 www.linear.com LINEAR TECHNOLOGY CORPORATION 2014