Voltage Feedback Control

The diagram below is a buck converter with a voltage-feedback control loop. The signal VOUT is connected to one of the two inputs of a network built around an op amp. This is the compensator (green box); the other input of this network is the constant value (the reference voltage, VREF), which represents the output voltage we want to get from the overall system.

The two functions performed by the op amp network (green box) are:

  • Compute the difference between the signal at its inputs (this signal is the error signal)
  • Implement a specific transfer function

The output of the compensator is compared to a sawtooth waveform so that the output of the comparator will be low when the sawtooth signal is smaller than the error and vice versa. A Pulse-Width Modulation (PWM) signal is thus generated. The flip-flops are needed to operate in Complementary mode using two switches in the power section.

voltge-feedback-control.png
© 2024 Microchip Technology, Inc.
Notice: ARM and Cortex are the registered trademarks of ARM Limited in the EU and other countries.
Information contained on this site regarding device applications and the like is provided only for your convenience and may be superseded by updates. It is your responsibility to ensure that your application meets with your specifications. MICROCHIP MAKES NO REPRESENTATIONS OR WARRANTIES OF ANY KIND WHETHER EXPRESS OR IMPLIED, WRITTEN OR ORAL, STATUTORY OR OTHERWISE, RELATED TO THE INFORMATION, INCLUDING BUT NOT LIMITED TO ITS CONDITION, QUALITY, PERFORMANCE, MERCHANTABILITY OR FITNESS FOR PURPOSE. Microchip disclaims all liability arising from this information and its use. Use of Microchip devices in life support and/or safety applications is entirely at the buyer's risk, and the buyer agrees to defend, indemnify and hold harmless Microchip from any and all damages, claims, suits, or expenses resulting from such use. No licenses are conveyed, implicitly or otherwise, under any Microchip intellectual property rights.