Piezoelectric Micropump Driver
Created: Jun 02, 2016
No description available.
In the medical industry, precision and accuracy are very important parameters. One aspect where these attributes are required is on controlled drug delivery, where medical pumps are used to infuse drug to a patient. Some known medical pumps used today are infusion pumps, insulin pumps and nebulizers. These pumps belong to microfluidics, which is a technology that deals with miniature devices that can pump, process and control small volumes of fluids. These micropumps are used to provide the actuation to transfer the drug from the drug reservoir to the body with accuracy and reliability.
This reference design is used to operate a piezoelectric micropump controlling the flow of fluid upon delivery. A micropump is a mini mechanical pumping device with a piezoelectric actuator and passive check valves. The design is mainly composed of the control board, high voltage driver board and the piezoelectric micropump. The control board is made up with the PIC16F1719 microcontroller (MCU) from Microchip. This board provides the power, the adjustable voltage and frequency control signals to high voltage driver board. It is powered through a 3.7V 700mAh Li-Polymer battery. The 3.3V, 3.7V and 5V voltage sources are supplied to different portions of circuitry through the use of MCP1711 LDO and the MCP1252 charge pump. The MCU sends five critical control signals to the high voltage board: HV_EN, HV_VREF, HV_DIN, HV_CLK and HV_LE. These control signals are transmitted to the high voltage driver board. The driver board delivers the boosted signals in specific waveforms on dual output channels, with adjustable peak-to-peak voltage and frequency, to the piezoelectric micropump. Through the software, both the pulse frequency and the peak-to-peak voltage can be controlled. The HV9150 DC/DC boost converter in the driver board converts the low supply voltage from the battery to 250V high supply voltage. This high supply voltage is used to power the HV513 driver IC to actuate the piezoelectric micropump.
The micropump is connected to the J101 of the high voltage driver board and is driven by the signal P1+ and P2+. The circuit can supply a maximum of 250V peak-to-peak voltage and a maximum frequency of 300Hz. This adjustability allows the basic driver to drive different types of piezoelectric micropumps on the market.