Negative Supply requirement in Sensor Electronics

Catering negative supply requirement

In sensor electronics,the most common component is Operational Amplifier(Opamp). Opamps are used for signal conditioning of Sensors . Opamp need two supplies, Positive and Negative voltage supply for its operation.

Problem Statement

In water quality testing projects, signal conditioning circuits of pH and EC sensors are needed. For signal conditioning of pH & EC sensors, Opamps are used and there arises a need for negative voltage supply.

For this purpose, negative supply can be developed by using:

• AC Step Down Transformer
• Bridge Rectifier
• Negative Voltage Regulator

Normally, the components needed for negative voltage supply are cost effective but the size of PCB board increases.

Solution

Solution for this problem is Voltage Inverter IC (TPS60400). It takes positive voltage and inverts into negative voltage.

Features of Voltage Inverter IC are :

• Inverts Input Supply Voltage
• Up to 60-mA Output Current
• Only three Small 1-µF Ceramic Capacitors needed
• Input Voltage Ranges from 1.6 V to 5.5 V
• Power Save-Mode for Improved Efficiency at Low Output Currents
• Device Quiescent Current Typical 65 µA
• Integrated Active Schottky-Diode for Start-up into load
• Small 5-Pin SOT-23 Package

The Voltage Inverter IC’s cost is very low and it carries a small size 5-pin IC. For water quality testing projects, this IC should be utilized.

Recommended Circuit of Voltage Inverter IC