EHE004

EHE004 Datasheet

EHE004

Part	Datasheet
EHE004	EHE004 (pdf)

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EHE004 ENERGY HARVESTING ELECTRONICS Simple and Easy Charge Management for Vibration Energy Harvesting Integrates directly with all Volture Energy Harvesters Parallel or Series Piezoelectric Connection Improved Efficiency User Selectable DC Output 1.8V, 2.5V, 3.3V, 3.6V Industrial Health Monitoring Network Sensors Condition Based Maintenance Sensors Wireless HVAC Sensors Mobile Asset Tracking Tire Pressure Sensors Oil and Gas Sensors All Air, Land, and Sea Vehicle Sensors Battery and Hard Wired Power Replacement Figure 1 Representative energy harvesting system using a Volture piezoelectric energy harvester and the EHE004 charge management electronics. The EHE004 is an energy harvesting power conditioning circuit, which converts the AC output from a piezoelectric energy harvester to a regulated DC output. The EHE004 consists of a full-wave rectifier with integrated charge management and DC-DC conversion, and connects directly to any Volture piezoelectric energy harvesting product. The DC output can be configured to the following voltage settings 1.8V, 2.5V, 3.3V, and 3.6V. The board includes 200 uF of storage capacitance onboard - more capacitance can be added if required. The EHE004 utilizes the Linear Technology LTC3588-1 piezoelectric charge management IC - designed to maximize total piezoelectric energy harvester output and mechanical-to-electrical conversion efficiency with medium to heavy loads. Each Volture energy harvesting product has two piezoelectric wafers. The EHE004 provides the user with ability to connect these wafers either in series or parallel. The series setting provides power output at lower g levels for small vibration amplitude applications. The parallel setting provides higher average power output levels at higher vibration amplitude levels. For more information please contact Mide Tech. Corp by emailing: CHARGE MANAGEMENT VSTORE EHE004 CHARGE MANAGEMENT SYSTEM SENSOR MICRO CONTROLLER SENSOR TX/RX SENSOR EHE004 ELECTRICAL CHARACTERISTICS PRINCIPLE OF OPERATION The LTC3588-1 Piezoelectric Energy Harvesting Power Supply from Linear Technology is the primary component on the EHE004. From Linear Technology’s datasheet: “The LTC3588-1 integrates a low-loss full-wave bridge rectifier with a high efficiency buck converter to form a complete energy harvesting solution optimized for high output impedance energy sources such as piezoelectric transducers. An ultralow quiescent current undervoltage lockout UVLO mode with a wide hysteresis window allows charge to accumulate on an input capacitor until the buck converter can efficiently transfer a portion of the stored charge to the output. In regulation, the LTC3588-1 enters a sleep state in which both input and output quiescent currents are minimal. The buck converter turns on and off as needed to maintain regulation. Four output voltages, 1.8V, 2.5V, 3.3V and 3.6V, are pin selectable with up to 100mA of continuous output current however, the output capacitor may be sized to service a higher output current burst. An input protective shunt set at 20V enables greater energy storage for a given amount of input capacitance.” Referring to Figure 2b, The LTC3588-1 power supply IC integrates an extremely low quiescent current voltage comparator with a highly efficient buck regulator. The buck regulator is activated when the rectified input voltage, VCAP, rises above the pre-set undervoltage lockout UVLO rising voltage threshold for the chosen output voltage setting Page 5 table ‘Specification’ . The regulator remains active until the input voltage has been depleted to the UVLO falling threshold, at which point the buck operation is disabled. Thus, for as long as the load demand exceeds the input power as in typical sensor or battery charger applications , the input voltage will hover between the UVLO rising and falling thresholds. In cases where the input power exceeds the load demand, the VCAP voltage will rise beyond the UVLO rising threshold, storing the excess power on the input capacitor. If the voltage at VCAP exceeds approximately 20VDC, an internal voltage clamp 5mA continuous rating prevents damage to the device. For more information on the LTC3588-1 please visit: EHE004 CONFIGURATION The EHE004 has two means of signal rectification Normal and Superseries and two ways to connect the two piezoelectric wafers in a Volture product Series and Parallel . There are also four options for the regulated DC output 1.8V, 2.5V, 3.3V, and 3.6V . In total there are sixteen possible configuration settings. The vibration environment and voltage requirements dictated by the application will determine the best configuration settings for the EHE004. Maximum Power Point The efficiency of power transfer from the piezo to the load, and thus normalized power mW/G , will be at maximum when the loaded piezo voltage for moderate to heavy loads, equal to the average UVLO voltage is approximately its open-circuit voltage. However, the ouput will continue to increase with increasing vibration amplitude. For light loads where VCAP is not depleted to the UVLO voltage during buck operation, transfer efficiency is inconsequential as more power is available than the load can use. Normal vs. “Superseries” The difference between ‘Normal’ and ‘Superseries’, is the bridge rectifier connection. In the normal mode of operation, the bridge rectifier is operated in fullbridge mode and its output voltage is half the peak-to-peak input voltage minus two diode drops. In the “superseries” configuration, the rectifier operates in a half-bridge mode with only one diode drop. The normal mode is recommended for maximum power output at moderate input voltages, however the halfbridge mode will allow operation from slightly lower minimum input voltages. Parallel vs. Series operation All of MIDE’s Volture products contain two piezo elements stacked in a bimorph configuration and pinned out independently, allowing the user to choose between parallel and series connection. On the EHE004 board, switch SW1 selects between parallel doubled current, lower input voltage and series doubled input voltage, lower current connection. Generally low level vibrations are best suited to the series configuration and high level vibrations are best suited to the parallel configuration. However, the optimal setting will depend on a number of factors including which Volture product is being used and the parameters of the vibration environment. The table below shows the general configuration settings for different application types. However, each application is unique and the optimal settings will depend on both the application and Volture or other piezoelectric element used for the energy conversion. Application Vibration Level Very Low Amplitude General EHE004 Configuration Settings SW1 SW3 Series Superseries Low to Moderate Amplitude Series or Superseries Moderate Amplitude Parallel Normal

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EHE004

ENERGY HARVESTING ELECTRONICS

Simple and Easy Charge Management for Vibration Energy Harvesting Integrates directly with all Volture Energy Harvesters Parallel or Series Piezoelectric Connection Improved Efficiency User Selectable DC Output 1.8V, 2.5V, 3.3V, 3.6V

Industrial Health Monitoring Network Sensors Condition Based Maintenance Sensors Wireless HVAC Sensors Mobile Asset Tracking Tire Pressure Sensors Oil and Gas Sensors All Air, Land, and Sea Vehicle Sensors Battery and Hard Wired Power Replacement

Figure 1 Representative energy harvesting system using a Volture piezoelectric energy harvester and the EHE004 charge management electronics.

The EHE004 is an energy harvesting power conditioning circuit, which converts the AC output from a piezoelectric energy harvester to a regulated DC output.

The EHE004 consists of a full-wave rectifier with integrated charge management and DC-DC conversion, and connects directly to any Volture piezoelectric energy harvesting product. The DC output can be configured to the following voltage settings 1.8V, 2.5V, 3.3V, and 3.6V. The board includes 200 uF of storage capacitance onboard - more capacitance can be added if required.

The EHE004 utilizes the Linear Technology LTC3588-1 piezoelectric charge management IC - designed to maximize total piezoelectric energy harvester output and mechanical-to-electrical conversion efficiency with medium to heavy loads.

Each Volture energy harvesting product has two piezoelectric wafers. The EHE004 provides the user with ability to connect these wafers either in series or parallel. The series setting provides power output at lower g levels for small vibration amplitude applications. The parallel setting provides higher average power output levels at higher vibration amplitude levels.

For more information please contact Mide Tech. Corp by emailing:

CHARGE

MANAGEMENT

VSTORE

EHE004 CHARGE MANAGEMENT SYSTEM

SENSOR

MICRO CONTROLLER

SENSOR

TX/RX SENSOR

EHE004

ELECTRICAL CHARACTERISTICS

PRINCIPLE OF OPERATION

The LTC3588-1 Piezoelectric Energy Harvesting Power Supply from Linear Technology is the primary component on the EHE004. From Linear Technology’s datasheet:
“The LTC3588-1 integrates a low-loss full-wave bridge rectifier with a high efficiency buck converter to form a complete energy harvesting solution optimized for high output impedance energy sources such as piezoelectric transducers. An ultralow quiescent current undervoltage lockout UVLO mode with a wide hysteresis window allows charge to accumulate on an input capacitor until the buck converter can efficiently transfer a portion of the stored charge to the output. In regulation, the LTC3588-1 enters a sleep state in which both input and output quiescent currents are minimal. The buck converter turns on and off as needed to maintain regulation.

Four output voltages, 1.8V, 2.5V, 3.3V and 3.6V, are pin selectable with up to 100mA of continuous output current however, the output capacitor may be sized to service a higher output current burst. An input protective shunt set at 20V enables greater energy storage for a given amount of input capacitance.”

Referring to Figure 2b, The LTC3588-1 power supply IC integrates an extremely low quiescent current voltage comparator with a highly efficient buck regulator. The buck regulator is activated when the rectified input voltage, VCAP, rises above the pre-set undervoltage lockout UVLO rising voltage threshold for the chosen output voltage setting Page 5 table ‘Specification’ . The regulator remains active until the input voltage has been depleted to the UVLO falling threshold, at which point the buck operation is disabled. Thus, for as long as the load demand exceeds the input power as in typical sensor or battery charger applications , the input voltage will hover between the UVLO rising and falling thresholds. In cases where the input power exceeds the load demand, the VCAP voltage will rise beyond the UVLO rising threshold, storing the excess power on the input capacitor. If the voltage at VCAP exceeds approximately 20VDC, an internal voltage clamp 5mA continuous rating prevents damage to the device.

For more information on the LTC3588-1 please visit:

EHE004

CONFIGURATION

The EHE004 has two means of signal rectification Normal and Superseries and two ways to connect the two piezoelectric wafers in a Volture product Series and Parallel . There are also four options for the regulated DC output 1.8V, 2.5V, 3.3V, and 3.6V . In total there are sixteen possible configuration settings. The vibration environment and voltage requirements dictated by the application will determine the best configuration settings for the EHE004.

Maximum Power Point The efficiency of power transfer from the piezo to the load, and thus normalized power mW/G , will be at maximum when the loaded piezo voltage for moderate to heavy loads, equal to the average UVLO voltage is approximately its open-circuit voltage. However, the ouput will continue to increase with increasing vibration amplitude. For light loads where VCAP is not depleted to the UVLO voltage during buck operation, transfer efficiency is inconsequential as more power is available than the load can use.

Normal vs. “Superseries” The difference between ‘Normal’ and ‘Superseries’, is the bridge rectifier connection. In the normal mode of operation, the bridge rectifier is operated in fullbridge mode and its output voltage is half the peak-to-peak input voltage minus two diode drops. In the “superseries” configuration, the rectifier operates in a half-bridge mode with only one diode drop. The normal mode is recommended for maximum power output at moderate input voltages, however the halfbridge mode will allow operation from slightly lower minimum input voltages.

Parallel vs. Series operation All of MIDE’s Volture products contain two piezo elements stacked in a bimorph configuration and pinned out independently, allowing the user to choose between parallel and series connection. On the EHE004 board, switch SW1 selects between parallel doubled current, lower input voltage and series doubled input voltage, lower current connection. Generally low level vibrations are best suited to the series configuration and high level vibrations are best suited to the parallel configuration. However, the optimal setting will depend on a number of factors including which Volture product is being used and the parameters of the vibration environment.

The table below shows the general configuration settings for different application types. However, each application is unique and the optimal settings will depend on both the application and Volture or other piezoelectric element used for the energy conversion.

Application Vibration Level

Very Low Amplitude

General EHE004 Configuration Settings

SW1 SW3

Series Superseries

Low to Moderate Amplitude Series or Superseries

Moderate Amplitude

Parallel Normal

Notice: we do not provide any warranties that information, datasheets, application notes, circuit diagrams, or software stored on this website are up-to-date or error free. The archived EHE004 Datasheet file may be downloaded here without warranties.

Datasheet ID: EHE004 649227