SPRADA5 April   2024 TMS320F28P550SJ , TMS320F28P559SJ-Q1

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
    1. 1.1 Supplementary Information
    2. 1.2 Features
    3. 1.3 Block Diagram
    4. 1.4 Operation Modes
  5. 2Use Cases
    1. 2.1 Buffer Mode for High-Impedance Source
    2. 2.2 Battery Voltage and Current Monitoring
    3. 2.3 Low-Side Shunt Current Monitoring
    4. 2.4 Three-Phase Low-Side Current Sensing
    5. 2.5 Bidirectional Current Sensing
    6. 2.6 Non-Inverting Amplifier for Low-Voltage Sensors
    7. 2.7 Non-Inverting Amplifier for Bipolar Signals
    8. 2.8 Standalone Mode for Various Applications
  6. 3Summary
  7. 4References

1 Introduction

The integrated PGA helps to reduce cost and design effort for many control applications that traditionally require external, standalone amplifiers. On-chip integration makes sure the PGA is compatible with the downstream analog-to-digital converter (ADC) and comparator subsystem (CMPSS) modules. Software-selectable gain, filter settings, and different operational modes make the PGA adaptable to various performance needs. The PGA module provides a desired gain when an input signal has insufficient amplitude. The PGA module can be placed in front of a comparator or ADC to increase the signal's amplitude.

Type-1 and Type-2 PGAs offer adjustable gain values to amplify the input signal but have some key differences.

  • Operation modes: Type-1 PGA only supports non-inverting mode, while Type-2 PGA can support buffer, standalone, non-inverting, and subtracting operation modes. Please note that Type-2 PGA module can operate as a unity-gain amplifier to drive the input circuit of a successive approximation-register (SAR) ADC.
  • Gain range: Type-1 PGA only provides 3x to 24x voltage gain, while Type-2 PGA offers programmable gain values of 2x to 64x. The wide gain range makes Type-2 PGA a good choice for various applications.
  • Low-pass filtering: In Type-2 PGA, two different low-pass filters can be implemented using either the embedded filter resistor or the gain resistor. The gain resistor, in combination with an external capacitor, helps the more stable operation of the PGA modules.