Picostrain Strain Gage Circuits

PS081 PICOSTRAIN

System-on-Chip for Strain Gauge Applications

The PS081 is a system-on-chip for ultra low power and high resolution strain gauge applications.

As a PS08 derivative, the PS081 also combines an ultra low power 24-Bit microprocessor with a high resolution T/D-converter (TDC) according to the known PICOSTRAIN measuring principle. An LCD controller and an EEPROM makes it a full featured System on Chip. Equipped with an extended memory range, enlarged ROM routines, enhanced IO-capabilities and an optional interface for external LCD driver control, the PS081 fulfills all requirements of coming generations of weigh scales, force sensors, pressure sensors or torque measurement systems in the consumer and the industrial market.

PicoStrain: Strain Gauge / Load Cells

The Most Powerful Combination of Low Power and Highest Accuracy.

The unique combination of a low power microprocessor with the PICOSTRAIN measuring unit shows impressive performance. The device reaches more than 28-Bit rms resolution and its excellent linearity and drift numbers are only comparable to absolute high-end Sigma-Delta A/D-converters. On the resolution side the PS081 makes it possible to get up to150,000 stable peak to peak divisions (at 2mV/V)! On the other hand a sophisticated power management together with the special features of the PICOSTRAIN method can reduce the total system current down to 15 µA, including the sensor current. Since the device is specified down to 2.2V it can be driven by a single lithium coin cell for a very long time. This will save costs and offers great advantages for wireless and battery driven systems.

Further features like the software adjustment of the offset and gain compensation or the possibility to operate with only one halfbridge opens the door to new and innovative solutions.

Get into the technology of the PS081 and save your competitive advantage with the worlds most innovative technology for strain gauges!

General Circuit Features

• PICOSTRAIN Front-End with up to 19.5 Bit resolution (@2mV/V)
• Capability to measure half-bridges, full-bridges, quattro-bridges and Wheatstone-bridges
• Microprocessor with 24-Bit data structure
• 2 k x 8-Bit EEprom progam memory including charge pump (no need of an additional programming voltage)
• 3 k ROM powerful program code like
• 48 Bit multiplication and division or binary to 7-segment conversion
• 8-layer hardware stack
  Embedded very low current 10 kHz oscillator (300 nA)
• Driver for external 4 MHz ceramic oscillator
• Operating current 0.7 µA with timer active
• up to 18 programmable I/O-ports
• 4 x 14, 3 x 15, 2 x 16 LCD driver, optional SPI to external LCD driver support
• Embedded charge pump for driving the LCD at 2.0 V, 2.5 V and 3.0 V
• Embedded bandgap voltage reference for low battery detection and LCD voltage stabilization
• Ports for temperature measurement with low-cost external carbon resistors
• Watchdog timer
• Serial SPI interface for EEPROM programming or operation with an external microprocessor
• Supply voltage 2.2 to 3.6 V at full functionality, down to 1.5 V without
• EEPROM reprogramming and voltage measurement
• System operational current down to 17 µA at 3 Hz and 2000 divisions
• As dice (115 µm pitch) or packaged (QFN56)

Additional Information