SBAA705 August   2025 ISOTMP35-Q1

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2ISOTMP35-Q1 Key Information for Design
    1. 2.1 Simplified Design Schematic to Sense Temperature
    2. 2.2 Temperature Transfer Table
  6. 3PWM Controller UCC28C43-Q1 Key Information for Design
    1. 3.1 UCC28C43-Q1 Internal Block Diagram
    2. 3.2 UCC28C43-Q1 Voltage Mode Setting
    3. 3.3 UCC28C43-Q1 Heating Frequency Setting
  7. 4OPA333-Q1 Key Information
  8. 5Air Heater Circuitry Design Sample
    1. 5.1 Working Mechanism Explanation
    2. 5.2 Air Heater Schematic Design
      1. 5.2.1 Working Condition
      2. 5.2.2 Design Procedure
  9. 6Typical Heater Schematic
  10. 7References

3.2 UCC28C43-Q1 Voltage Mode Setting

Figure 3-1 shows a way to set voltage mode, in heater application, voltage mode can be used since there is no current loop in circuitry, T1, R6, R2 combination forms voltage mode control. T1 2N2222 is NPN transistor, this acts as voltage follower, so there can be a same shape of saw waveform on CS pin as RT/CT pin, R6 and R2 is used to adjust the amplitude of saw waveform on CS pin, in simple words, CS pin can act as just like saw or triangle waveform input port, the error signal from error amplifier on UCC28C43-Q1 is sent to the inverse input of comparator so as to realize PWM feature.

Voltage Mode Setting Figure 3-2 Voltage Mode Setting