The Comparator

The comparator significantly influences the quality of the measurement. It is not integrated in the PSØ2. It is possible to get results of outstanding quality using a very simple bipolar comparator circuit as shown in the figure. The circuit is very insensitive to low supply voltage. When driving the chip with Vcc and Vio at the lower limit of 1.8 V, the absolute noise is still less than with 5 V - a proof of the power and robustness of this simple and low-cost measuring principle.

This comparator has a quiescent current of about 80 µA at 3 V supply voltage.

• Features
• Schematic Diagram
• Connecting the Bridge
• Capacitor Choice
• Comparator
• Oscillator
• Cycle Time
• Averaging/Resolution
• Rdson Compensation
• Gain Compensation
• Temperature Measurment
• Capacitor Measurement