SBAA598 September   2023 AMC1300 , AMC1300B-Q1 , AMC1301 , AMC1301-Q1 , AMC1302 , AMC1302-Q1 , AMC1311 , AMC1350 , AMC1351

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2Bootstrap Power Supply Design
    1. 2.1 Selection of Charge Pump Capacitor
    2. 2.2 Simulation in TINA-TI
    3. 2.3 Hardware Test with AMC1311-Q1
  6. 3Summary
  7. 4Reference

3 Summary

A charge-pump bootstrap circuit is an effective way to produce an isolated power rail for an isolated amplifier in PWM applications. A well-designed boostrap power supply can operate just as effectively as a clean power supply, while saving space and cost.

There are several key factors to consider when designing a bootstrap circuit. It is important to know the current draw of the isolated amplifier, the frequency and duty cycle of the PWM signal, the allowable range for circuit start-up time, and the allowable power supply ripple for the isolated amplifier. All of these specifications can affect the selection of the RC circuit used in the bootstrap circuit. A bootstrap can be simulated easily, making the selection process much simpler since the designer can easily test various RC values under different circuit conditions.